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Alice - PDS Small Bodies Node

1. 27 Figure 3 1 1 The Alice entrance slit design a The physical dimensions of the slit b The slit orientation with respect to the DDL detector image spatial axis and the spacecraft axes 35 Figure 3 1 2 Left Schematic of the Alice DDL detector vacuum housing Right Photograph of the DDL detector vacuum housing s ssesssssrerrrersrssrrrsrrssresrrrsrrssrrsr enne entren enne eene nnn entrer en 36 Figure 3 1 3 The Alice electrical block diagram seen 38 Figure 4 1 1 The Alice top level mode transitions esee enne nennen 58 Figure 6 10 1 amare eR RH Re 95 Figure 6 10 2 Alice S T B ect onere te Rar te ree ree tene Eee eet 95 LIST OF TABLES Figure 1 3 1 The opto mechanical layout of Alice esee nnne nennen nen 11 Figure 1 3 2 External view of Alie insoti 12 Figure 1 3 3 Photograph of the Alice protoflight model with the top cover removed 12 Figure 1 3 4 Block diagram of Alice cree ere Pn c 12 Fig re 2 2 1 The Alice power System rere ete SER RI ari ne ra hee a 14 Figure 2 2 2 Alice telecommand interface circuit essere ner sr ene rn on 17 Figure 2 2 3 Alice telemetry interface circuit eene nennen nennen sr ene rn on 17 Figured Alice memory
2. gt ALTERNATE Shift Register 000670 Figure 2 2 3 Alice telemetry interface circuit 2175 CIRCUIT EID A PRIME ENABLE PRIME TELEMETRY DRIVER CIRCUIT EID A PRIME TELEMETRY REDUNDANT TELEMETRY ALTERNATE DRIVER REDUNDANT i i CIRCUIT EID a TELEMETRY 1 m REDUNDANT i o ALTERNATE CLK i REDUNDANT CLK i EID A 1 REDUNDANT ALTERNATE ENABLE 4 REDUNDANT CIRCUIT ED ENABLE FIFO READ EDAC READBACK INTERRUPT Rosetta ALICE User Manual 2 2 4 Instrument Heaters Alice has two sets of redundant heaters on the optics OAP mirror and grating that allows for decontamination of the optics during flight as required These two heaters are controlled by the Alice C amp DH electronics In addition to these two heater sets non ops survival heater is located the side of the instrument housing that is controlled by the spacecraft The non ops heater location is shown in the Alice thermal interface control drawing see Attachment 1 2 2 5 Instrument Thermistors Housekeeping Sensors Table 2 5 shows the location of all Alice thermistors and other housekeeping sensors Table 2 5 Alice thermistors and other housekeeping sensors Desc
3. EXPERIMENT USER MANUAL Version 2 Protoflight Model March 2010 SwRI Project No 15 8225 Document No 8225 EUM 01 Rev I DRD 65 3 JPL Contract 1200328 Prepared by gt em In MENEN SOUTHWEST RESEARCH INSTITUTE H Space Science and Engineering Division 6220 Culebra Road San Antonio Texas 78228 0510 le EA 210 684 5111 FAX 210 543 0052 X TS R I Aa EXPERIMENT USER MANUAL Version 2 Protoflight Model SwRI Project 15 8225 Document No 8225 EUM 01 Rev 0 DRD 65 3 Contract JPL 1200328 Prepared by Reviewed by Reviewed by Reviewed by Reviewed by Reviewed by D C Slater Project Scientist Date December 2006 Date S A Stern Principal Investigator Date J Wm Parker Project Manager Date M Versteeg Lead Software Engineer Date P B Gupta P A Engineer Date ESA Representative Instrumentation and Space Research Division Southwest Research Institute P O Drawer 28510 6220 Culebra Road San Antonio Texas 78228 0510 210 684 5111 ma TABLE CONTENTS DOCUMENTATION CHANGE RECORD ssssoso0o0o0000c00c0c00s000000c0c00c000s0ssorssr0rssrrsrsrrsrsrrsrerrosenrnsrersesr enes LIST OF ACRONYMS AND ABBREVIATIONS cccsccssssssssssssessesssesesssssesssssssssscsesssesessnsesesesessssesesssesees cess vii 1 GENERAL DESCRIP
4. A D AFT APID BOL BT C amp DH CCP CCSDS D D DDL DDS EEPROM EGSE EID EMC EMI EOL ESA ESD ESD EUV FFT FOV FUV GN GSE HK HTR HV HVPS ICD IFOV IST LCL MAD MCP MICD MST NVR OAP OBDH OSIRIS PAD PAIP PFM LIST OF ACRONYMS AND ABBREVIATIONS Aperture Door Abbreviated Functional Test Application Process Identification Beginning of Life Bench Test Command and Data Handling Electronics Contamination Control Plan Consultative Committee for Space Data Systems Detector Door Double Delay Line Data Disposition System Electrically Erasable Programmable Read Only Memory Electrical Ground Support Equipment Experiment Interface Document Electromagnetic Compatibility Electromagnetic Interference End of Life European Space Agency Electrostatic Discharge Electrostatic Discharge Extreme Ultraviolet Full Functional Test Field of View Far Ultraviolet Gaseous Nitrogen Ground Support Equipment Housekeeping Heater High Voltage High Voltage Power Supply Interface Control Document Instantaneous Field of View Integrated System Test Latching Current Limiter Multiple Acquire Dump Microchannel Plate Mechanical Interface Control Document Mission Simulation Test Non Volatile Residue Off Axis Paraboloid On Board Data Handling Optical Spectroscopic and Infrared Remote Imaging System Filler field in CCSDS packets used to return TC token into TM packet Product Assurance Implementation Pla
5. t e ren b ee pee DD Ee torte 34 3 1 3 Entrance Shit Le etel eh 36 3 1 4 Detector and Detector Electronics eee tede i 36 3 1 5 Electrical Design ie e n 38 3 1 6 Data CollectioniModes 4 a e ta e eee eee eL eee tede den 39 3 1 7 Detector Acquisition D rdtiOns e BUE ebat tet lans 40 3 1 8 Analog versus Digital Detector Count Rates and Rate Doubling sss 41 3 1 9 Code Memory 42 3 1 10 Software Code Patch Operation esses eene eene eren rentre trennen 42 3 1 11 In Flight Aperture Door Performance 20 2 0 2 000000000000000 43 J112 Fail Safe Door Activation 3 tte E ee ee e RS 44 3 2 OPERATING MODES n rere ch eee e ere e tas rre Fo ror dre dipinto 44 3 231 Ground Test Plan from Alice EID B OJ somseessesserssrssrrserssrrsrrrrrrrrrrrrsrr 44 3 2 2 Inz rbit Commissioning dh tee See e i ah 45 3 2 3 Instrument Checkout In Flight Calibration esee eene 48 3 2 4 Flight Operations Plans per Mission 49 11 A 4 3 2 5 INTE CK ENCES B
6. 1 3 2 3 Att 2 2 2 4 2 2 5 3 1 3 2 3 4 1 1 08 2006 Updated Section 1 3 replaced Fig 1 3 3 with simpler instrument block diagram inserted a photograph of the Alice PFM Moved attachment 2 On board Software and Autonomous Functions into the main document in Sections 2 3 and 6 Added Standard Sequences document in Attachment 2 Added descriptions Section 2 2 4 Instrument Heaters and Section 2 2 5 Instrument Thermistors Housekeeping Sensors Added power table per operational mode Table 2 12 Replaced Operating Principles Section 3 1 with updated comprehensive instrument description and function description Updated Nominal Operational Plans Section 3 2 and Mode Descriptions Section 4 Added Section 7 describing and STB Moved Attachment 13 Alice Flight Rules and to Section 3 4 of main document Added team list 2 0 2 3 5 2 4 3 3 1 3 3 1 4 3 1 6 3 1 7 3 1 8 6 10 11 2006 Updated List of Acronyms and Abbreviations Added Version 2 05 flight software description Updated Table Acquisition data volume modifiers Updated and added new slit design figure Updated and added figure of DDL detector Minor updates Minor updates Minor updates Added introductory paragraph description Added new Version 2 05 FSW PAD field handling functionality Added new section describing the Alice EQM and STB 2 1 2 5 03 2010 Updated Flight Data Archive plan section vi
7. Ji Rosetta ALICE User Manual This new release includes the addition of a special variant of the pixel list acquisition function that is optimized to perform successive pixel list acquisitions with minimal time in between the active acquisition operations This operating mode optimizes the acquisition of small pixel list acquisitions and will be referred to as Perpetual Pixel list capability This mode can be used to perform pixel list acquisitions with minimized gaps in between the separate acquisitions It assumes that the spacecraft data handling system can on average keep up with the generated data and the instrument internal FIFO is sufficient provide some buffering of the generated TM packets This Perpetual Pixel list capability is a software attempt to mimic the PERSI Alice continuous pixel list acquisitions within the limitations of the existing software structure The changes for this mode include e Optimize the instrument internal data transfer and formatting of the pixel list science packets for one TM packet pixel list acquisitions less than 1931 events e More frequent check of the end condition for pixel list acquisitions from once per second to five times per second e Optimize instrument internal data transfer to send the generated TM packets to the 16 kbyte TM FIFO that hold the generated TM packets e Special MAD cycle specification that will continue the MAD cycles until explicitly commanded to stop In additi
8. DATA CLOCK FIFO DATA STROBE SERIAL VO ND CLOCK rae COMMAND CLOC COMMAND COMMAND STROBE FPGAREAD INCREMENT WRITE DETECTOR DDL ELECTRONICS DETECTOR CONTROL PROCESSOR 32K RAM 16K ROM HV CONTROL INSTRUMENT COVER CONTROL DC DC CONVERTER 5V INSTRUMENT COVER LAT MOTOR HEATERS EN x2 SWITCH TA005046 Figure 3 1 3 The Alice electrical block diagram 28 V SC POWER Power Controller Electronics The PCE are composed of DC DC converters designed to convert the spacecraft power to 5 V DC required by the detector electronics the C amp DH and TM interface electronics and the detector HVPS Also located in the PCE is the switching circuit for the heaters and the limited angle torque LAT motor controller that operates the front aperture door Command and Data Handling Electronics The C amp DH electronics handles the following instrument functions i the interpretation and execution of commands to the instrument ii detector acquisition control including the histogramming of raw detector event data iii telemetry formatting of both science and housekeeping data iv control of the detector HVPS v the detector vacuum cover release 38 Rosetta ALICE User Manual mechanism vi the front aperture door control vii the control of the housekeeping analog to digital converters ADCs which are used to conve
9. i Alice shall have all measured temperatures within their nominal operating range i e 20 lt T lt 50 at the temperature reference point ii Real time contact is strongly desired iii HV shall be off iv The aperture door or fail safe door shall be open v Both the mirror and grating heaters shall be turned on vi Detector door opening shall not be commanded until the corresponding measured temperatures indicate an increase of at least 10 degrees 07 FAIL SAFE DOOR OPERATION FSD FSD 1 Approval for Opening i Because the fail safe door cannot be closed after opening the aperture door shall be certified as permanently inoperable prior to FSD opening ii The PI and PM must both provide written approval prior to FSD opening FSD 2 Opening i Alice shall be in a safe attitude ii Alice shall have all measured temperatures within their nominal operating range i e 20 lt T lt 50 C at the temperature reference point iii HV shall be off iv Near real time monitoring is desired 08 HEATER OPERATIONS HOP HOP 1 Operations i There does not exist a maximum heater operation time 53 Rosetta ALICE User Manual 09 PERMANENT PARAMETER LIST UPDATE PLU PLU 1 Certification i The PM must authorize any update of the permanent parameter list saved in the Alice context in writing ii Such authorization including the revised Parameter List and the reason for each change shall be recorded in
10. 5th Edition HD RA 2000 Dec Spectral Name Count s 886 00 13 14 2 15 11 01 2 83 B2IV 88Gam Peg 17240 5394 00 56 42 5 60 42 60 2 47 BOIVe 27Gam Cas 65222 10144 01 37 42 9 57 14 12 0 46 B3Vpe Alp Eri 107707 24398 03 54 07 9 31 53 01 2 85 44Zet Per 32207 24760 03 57 51 2 40 00 37 2 89 BO 5V A2V 45Eps Per 44299 24912 03 58 57 9 35 47 28 4 04 OT 5III n f 46Xi Per 25411 30614 04 54 03 0 66 20 34 4 29 09 5Ia 9 1 Cam 16230 31237 04 54 15 1 02 26 26 3 72 B3III B0V 8Pi 50ri 20625 34085 05 14 32 3 08 12 06 0 12 B8Ia 19Bet Ori 15429 35411 05 24 28 6 02 23 49 3 36 B1V B2e 28Eta Ori 20135 35468 05 25 07 9 06 20 59 1 64 21 24Gam Ori 51589 36486 05 32 00 4 00 17 57 2429 OQSILI 34Del Ori 108224 36861 405 35 08 3 09 56 03 3 54 O8III f 39Lam Ori 36283 37043 05 35 26 0 05 54 36 2c po LOOIIT 44Tot Ori 65815 37128 05 36 12 8 01 12 07 1 70 BOIa 46Eps Ori 132554 37468 05 38 44 8 02 35 60 3 81 09 5 48514 Ori 25253 37742 05 40 45 5 01 56 34 2 05 O09 Db 50Zet Ori 127740 38771 05 47 45 4 09 40 11 2 06 BO 5Ia 53Kap Ori 95146 44743 06 22 42 0 17 57 21 1 98 2Bet 71772 52089 06 58 37 5 28 58 20 1 50 B2II 21 CMa 58689 66811 08 03 35 1 40 00 12 2325 DE Zet Pup 157085 68273 08 09 32 0 47 20 12 1 78 WC8 09I Gam2Vel 278424 71129 08 22 30 8 59 30235 1 86 KS3III B2 V Eps Car 42126 81188 09 22 06 8 55 00 39 2 50 B2IV V Kap Vel 233
11. Alice has one defined housekeeping packet SID 1 which has a data field size of 46 octets Housekeeping generation begins when an enable housekeeping telecommand is received or within approximately 60 seconds after startup if no enable command is received When enabled housekeeping packets are generated at a configurable rate The default rate is one packet per 30 seconds but this can be modified by changing an operating parameter in the parameter file Alice also has defined a supplemental diagnostic data packet This packet is defined as a science packet so it is not visible to DMS HK processing algorithm This packet is produced at the same time as a housekeeping packet if it is enabled It is enabled or disabled by a parameter in the parameter file In normal operation generation of this packet is disabled Alice makes use of the event service both for notification of actions within the instrument and to indicate error conditions Event packets are generated for the following reasons At software startup with self test information normal When the door moves normal When the high voltage is changed normal When the door does not move as expected warning When there is a correctable error reading the parameter file warning When there is a non correctable error reading the parameter file on board When there is a safety condition on board ground configurable When the acquire phase of the MultipleAcquireDump telecommand starts
12. Aperture door close sensor always indicates closed If the aperture door close sensor continues to indicate closed after commanding open then a door warning event will be generated If this happens the Alice team will request time to perform engineering diagnostics The indication from the door open sensor will be considered If it behaves as expected then the door close sensor will be suspected faulty One or more science observations will be made to determine if the door is really open in which case the sensor will be declared faulty If this happens then operation will proceed normally with the understanding that the door close sensor is faulty If it appears The detector vacuum housing is backfilled with GN during launch to prevent degradation of the sensitive detector photocathodes from exposure to air that could leak into the housing if left under vacuum 61 Rosetta ALICE User Manual that the sensor is correctly indicating that the door remains closed then several re attempts will be made to open the door possibly including lengthening the amount of time that the door motor is activated this is a configurable parameter If it determined that the door is actually stuck closed and cannot be opened then at some point the decision will be made to open the fail safe door which is a one time operation This decision would likely be made only after some amount of time has passed and the Alice team feels certain that the door is p
13. S C slew operations 1 the Alice HVPS shall be powered to a non sensitive level x 2500 volts or off to an MCP output voltage of 0 volts and or ii the aperture door shall be closed 5 S C thruster firings i The Alice HVPS shall be powered off to an MCP output voltage of 0 volts during any Rosetta spacecraft thruster firings 04 LAUNCH LATCH OPERATION LATCH t LATCH 1 Opening i Alice shall be in a safe attitude ii HV shall be off iii Alice shall have all measured temperatures within their nominal operating range 1 20 lt T lt 50 C at the temperature reference point 52 Rosetta ALICE User Manual 05 APERTURE DOOR OPERATIONS AD AD 1 Opening i The Aperture Door open command shall be a critical command ii Alice shall be in a safe attitude iii Alice shall have all predicted temperatures within their nominal operating range i e 20 lt T lt 50 C at the temperature reference point AD 2 Maintenance i The LAT motor of the aperture door shall be cycled a minimum of 20 times 10 cycles per flight year AD 3 Total Cycles i The planned number of door cycles after launch will not exceed 10 000 for a safety factor of 2 Door cycles must be rationed accordingly AD 4 S C thruster firings i Unless otherwise stated by the Alice team the aperture door shall be closed during planned Rosetta spacecraft thruster firings 06 DETECTOR DOOR OPERATION DD DD 1 First DD Opening
14. Structure ID 8 data Data Field Information Data Field Field Structure Remarks enum 16 see notes values for FailureCode 1 execution error Telemetry Packet Definition Alice Packet Name Housekeeping Alice Packet Function Provide Alice routine housekeeping data Generation Rules Periodic when enabled default rate is 30 seconds configurable by parameter Process ID Packet Category Service Type Structure ID data Data Field Information Remarks 79 Rosetta ALICE User Manual HkHvOn enum 1 high voltage arm indication from sensor 0 off most significant bit of 8 bits bit field 1 HkDetStim enum 1 detector stimulator indication 0 stim off 1 stim on count rate acquisition mode true count rate mode if true then HkAcqMode below is don t care HkAcqMode enum 1 hardware acquisition mode 0 pixel list 1 histogram HkAcqActive enum 1 acquisition hardware active 0 not active 1 active HkDetDoor enum 1 indicates detector door position from sensor 0 open 1 closed HkApDoor enum 2 indicates aperture door position from sensor 0 error least significant bits of bit field 1 7 closed 2 open 3 in between EEPromCode enum 1 corrently executing code 0 PROM code 1 EEPROM code HkState enum 3 operating state 0 checkout 1 acquire 2 dump 3 safe 4 hold 5 safedump 6 7 unused EEPromPage enum 2 Current active EEPROM page when executing EEPROM code 0
15. The main use of the EEPROM memory however is to be able to perform code patches Using telecommands memory load new code may be uploaded and installed in the instrument to correct certain defects that have been found or to implement improved changed operational code Once uploaded this code becomes available for execution and by means of a telecommand Alice can be instructed to start executing this new code Note that after power up the instrument still starts executing the code in PROM and that this code is used to make the jump to the newly loaded code The Alice C amp DH also contains general purpose data storage memory RAM About 50 of this memory is used during normal system operations to store variables and to create some data buffers Using telecommands executable code could also be uploaded into this RAM memory and even be executed directly in RAM using again the same telecommand mechanism This execution may be useful in two specific cases 1 when a test or diagnostic function is needed once it may just be uploaded in RAM and executed there once the test is completed and the instrument is switched off the memory contents will be lost and 2 to possibly store code patches that are needed for instrument operation when the EEPROM is not available because of a failure The disadvantage of these patches would be that these have to be reloaded each time after a power cycle Note The lifetime of the EEPROM memory is after derating limit
16. based on thermal models and collected flight data to that point in the mission and those times will be set in the timeline High voltage safety condition If any of several HV power supply operating parameters goes out of limits then a high voltage safety condition will be in effect and Alice will be safed A safety event telemetry packet will be generated If this happens then the Alice team will request time to perform engineering diagnostics Tests will be performed on the HVPS to determine if the problem is temporary or permanent If the problem is temporary and can be explained then normal operation will resume If it appears that a normal operating 62 Rosetta ALICE User Manual parameter has changed due to aging for example then the safety threshold limits can be adjusted to account for the new operating parameters Temperature safety condition If any temperature sensor exceeds a preset limit then a temperature safety will be in effect and Alice will be safed A safety event telemetry packet will be generated The data in the packet will indicate which temperature sensor caused the safety Ifitis determined that the temperature sensor in question is faulty then that temperature sensor can be excluded by setting a parameter from being considered in future temperature safety determination If the temperature sensor is reading just a little above the limit and this is determined acceptable then the temperature safety limi
17. gt 100 kHz The first path is used by the C amp DH to acquire the data for both histogram and pixel list acquisition modes and depending on the selected acquisition mode the acquisition hardware stores data in the acquisition buffer The second path is used by the C amp DH to count the instantaneous count rate the number of photons detected per unit of time This data is used for the instrument safety checking is reported in housekeeping data and is used by the software in the count rate acquisition mode The first two uses determine a per second count rate and the count rate acquisition determines the count rate based on the time period specified for the count rate acquisition 3 ms 11 9 s The detector electronics includes a feature in which the generation of the digital event data stream activated on both histogram and pixel list hardware acquisition modes influences the detector level of A Rosetta ALICE User Manual the raw analog events Roughly the activation of the digital interface will result in a doubling of the number of events reported on the raw analog interface due to a switching bounce This undesired behavior was found too late in the instrument development to be corrected The resulting effect of this feature is that whenever a histogram or pixel list acquisition is active the reported analog count rate which is based on the raw analog event rate is about double the actual rate Since this count rate is internally
18. it is necessary to pump down the Alice detector housing to a high vacuum level lt 107 Torr using the Alice GSE vacuum pump station and associated GSE vacuum manifold see Figure 2 2 1b A special GSE rack contains the vac ion HVPSs and pressure gauge controller necessary to operate the vacuum manifold during the SPT Long HV cables 5 m connect this rack with the vac ion pumps and CCG gauge on the manifold Following the completion of the SPT the detector vacuum housing must backfilled with high purity grade GN MIL P 27401C Grade C or better Attachment 6 contains the detector vacuum pumpdown and backfill procedure 8225 DET PUMPDOWN 01 The SPT test must only be run with Alice team members present The HV safing plug must be removed to run this test Abbreviated Functional Test AFT The Alice AFT is a limited functional test of the Alice instrument excluding operation of the detector HVPS This test will be conducted using the Alice Abbreviated Functional Test scripts as outlined in SwRI Technical Note Test Sequence Definitions for Alice Flight Software 8225 TEST_DEF 01 see attachment 4 It will be performed 1 following the S C acoustic shock tests 2 during the S C thermal balance thermal vacuum test and 3 to verify system electrical integrity following local movement of the S C when necessary System Validation Test SVT The SVT is a closed loop test of the S C the Alice payload the overall ground segment and the fligh
19. the ALICE switch ON procedure Recovery action ALICE switch OFF OBCP 8012 40006 Call engineer 40006 Call engineer This event is on the on board event monitoring list service 12 Its recovery action shall be enabled by the ALICE switch ON procedure Recovery action ALICE switch OFF OBCP 8012 NALAO002 Ins Det Cnt Rate NONE LAL00023 engineer NALA0003 Min Det Cnt Rate LAL00023 Call engineer NALA0004 Max Det Cnt Rate LAL00023 Call engineer Call engineer for ALICE has entered unsafe investigation conditions First action call and check instrument status Which alarm has triggered is indicated by the safety flags NALD0107 Operating State LAL00041 Call engineer for ALICE TM reports illegal investigation operating state NALD0501 HV Set Point ANA kV LAL00040 Call engineer NALD0502 Ins MCP Voltage ANA 1 1 00024 Call engineer NALDO601 Min MCP Voltage ANA kV LAL00024 Call engineer NALD0602 Max MCP Voltage ANA kV LAL00024 Call engineer NALDO701 Ins Anod Voltage ANA V LAL00025 The OOL is expected if it This parameter is occurs while parameter expected for a few NALDO101 switched from samples after ALICE High OFF to ON Otherwise call Voltage switch on engineer NALDO101 changes from Off to ON NALD0702 Min Anod Voltage ANA IV LAL00025 The OOL is expected if it This parameter is occurs while parameter expected for a few NALDO10
20. 1 S C monitored Alice parameters added further description of Alice return to safe state during MAD acquisition sequences 7 11 Added the Alice Hot UV Star List Attachment 11 1 5 3 4 10 2004 Added new flight rule the detector HVPS shall not be on during any spacecraft thruster firings 2 5 3 01 2005 Added diagnostic data description 3 1 3 01 2005 Added descriptions of active and passive checkouts 3 1 12 01 2005 Added section In Flight Aperture Door Performance Tests V Ver Rev Section Date Changes 7 11 7 12 3 4 01 2005 01 2005 02 2005 Updated the UV Hot Start List based on latest in flight calibration results Added Attachment 12 In Flight Aperture Door Performance Tests to describe results of tests to date Replaced Operational Constraints section with a reference to the formal Alice Flight Rules document placed as an Attachment 13 to the User Manual 1 6 3 13 Att 13 04 2005 04 2005 Updated plan for passive and active checkouts Flight rules now permanent attachment to this document and no longer maintained as a separate document General reformatting Change Flight Rule BRT 2 clarifying that solar elongation limits are applicable whenever Alice is ON not just at a particular voltage Change Flight Rule BRT 3 to read HV gt 2500 rather than gt 250 Changed 4 to allow for turning down to 2500 2 0
21. 1 to 3968 3 ms to 11 9 s with a good resolution at the low end Up to 8 dump specifications can be used that will be executed in sequence unused dump specification slots are indicated by setting the CollapseSpatial specification to zero Not all parameters used in a dump specification are applicable for all acquisition modes histogram acquisition mode all parameters are applicable the collapse factors specify the number of pixels summed together in the spatial respective spectral dimension and should specify an integer factor of the corresponding window size pixel list acquisitions modes only window specifications are applicable count rate mode no window or collapse can be specified In each case the Collapse spatial field is used to indicate a used dump specification for the pixel list and count rate modes this means that this field should be set to a non zero value Telecommand Packet Definition Alice Packet Name Reset Telemetry Output Buffer Packet Function requests instrument reset telemetry output hardware and software Verification Rules acceptance always Header Information Data Field Information Data Field Remarks p 6 2 Telemetry Packet and Parameter Definitions Telemetry Packet Definition Alice Packet Name Telecommand Acceptance Success Alice Packet Function acknowledge successful acceptance of telecommand packet Generation Rules on acceptance of telecommand with acceptance acknowledge header bit
22. 4 anode voltage fail counter number of consecutive failures before safety is raised 22 HVFAILMCP 4 fail counter number of consecutive failures before safety is raised 23 HVFAILSTRIP 4 strip current fail counter number of consecutive failures before safety is raised 24 DOORTIMEOUT 2 aperture door motion timeout approximately specified in seconds 25 COUNTERINTERVAL 10 detector count rate time base kernel ticks 26 COUNTSLOTS 100 count rate slots for histo mode fixed at compile time do not change unless recompiling software 27 MAXPRESSURE 21 1 5 mbar maximum accepted Rosina pressure both for alert and trend safety in Rosina real format see EID B 28 PRESSTIMEMARGIN 60 pressure trend time margin in seconds 10 29 MAXTEMP 192 58 C max allowed temperature specified in ADC counts 30 TEMPMASK 255 temperature sensor bit mask all temperature sensors enabled specified in same order as reported in HK packet 31 HTRTOLGRATING 8 grating temperature tolerance ADC counts 32 HTRTOLMIRROR 8 grating temperature tolerance ADC counts 33 TESTMASK 0 self test bit mask no tests selected 34 HKRATE 30 housekeeping rate in seconds 35 DGENABLE 0 additional diagnostics data generation disabled 36 37 MAXCOUNTRATE 40000 max allowed counts per interval 16 bits 38 39 SAFETYTIMEOUT 600 safety timeout in seconds 16 bits 40 41 MAXDUST 30 dust flux limit in counts sqm min GIADA 91 Rosetta ALICE User Manual 6 6 Data and Dump File Definit
23. A ice investigation are to characterize the composition of the nucleus and coma and the coma nucleus of comet 67P Churyumov Gerasimenko This will be accomplished through the observation of spectral features in the 700 2050 EUV FUV region Alice will provide measurements of noble gas abundances in the coma the atomic budget in the coma major ion abundances in the tail and in the region where solar wind particles interact with the ionosphere of the comet determine the production rates variability the structure of H2O CO and gas surrounding the nucleus and the far UV properties of solid grains in the coma Alice will also map the cometary nucleus in the FUV and study Mars the Rosetta asteroid flyby targets Steins and Lutetia and targets of opportunity while en route to Churyumov Gerasimenko Ultraviolet spectroscopy is a powerful tool for studying astrophysical objects and has been applied with dramatic success to the study of comets Alice will provide unprecedented improvements in sensitivity and spatial resolution over previous cometary UV observations For example A ice will move the sensitivity threshold from the 1 Rayleigh level achievable with the Hubble Space Telescope to the milliRayleigh level in deep integrations In addition Alice will by virtue of its location at the comet move the spatial exploration of nucleus UV surface properties from the present day state of the art i e no data available on any comet to complete
24. B6 5V Mu 15 26058 157246 17 25 23 6 56 22 39 3 34 20509 158408 17 30 45 8 37 17 45 2 69 B2IV 34Ups Sco 19613 158427 17 31 50 5 49 52 34 2 95 B2Vne Alp Ara 15436 158926 17 33 36 5 37 06 14 1 63 B2IV B 35Lam Sco 52066 160578 17 42 29 3 39 01 48 2 41 5 Kap Sco 48301 1751917 1825591529 262 7248 2 02 B2 5V 34Sig Sgr 36354 193924 20 25 38 9 56 44 06 1 94 B2IV Alp Pav 39134 205021 215 20239 6 70 33 39 3 23 BLIV 8Bet Cep 22696 Total Bad Dog stars 57 WC v lt 4 95 1 05 V 4 80 1 07 V lt 4 61 1 08 V lt 4 50 1 09 V lt 4 38 6 BO V 4 07 10 V 3 68 17 B2 V 2 98 16 B3 V 2 60 2 B4 V 2 14 1 B8 V 0 13 1 The magnitudes as a function of spectral type listed above can be used as a rough guideline for identifying Bad Dogs The actual UV flux is a strong function of the reddening of the star 108 Rosetta ALICE User Manual ATTACHMENT 12 Alice In Flight Aperture Door Performance Test Results During the software patch verification the added door performance test function was used for the first time Four cycles were performed showing very constant operation times average operation times were 9 2 2004 Start movement End movement Door open 17 9 ms 70 0 ms Door close 17 1 ms 76 5 ms A more extensive door measurement was scheduled as a separate commissioning activity on 9 28 2004 These measurements were executed 4 quick cycles in
25. Field Safetyld enum 4 safety condition identifier 0 dust 1 bright 2 pres trend 3 pres alert 4 HVPS error 5 over temp 6 14 unused 15 affect all SafetyMasked boolean 1 mask state true masked Notes critical Telecommand Packet Definition Alice Packet Name Set safety override Packet Function sets the state of the safety override Verification Rules acceptance always execution always after confirmation Header Information Packet Catego Service Type Service Subtype Data Field Information Data Field Remarks unused SafetyOverride safety override true override Notes critical Telecommand Packet Definition Alice Packet Name Packet Function opens the aperture door Verification Rules acceptance must be in checkout state execution must still be in checkout state so no safety condition active after confirmation Process ID 12 Service Type 14 Structure ID 0 data Data Field Field Structure Roe 7 Notes critical Since this is critical telecommand there can be a time delay between acceptance and execution Therefore the state is checked for acceptance and again for execution It is possible that the telecommand could be accepted but not executed if the state changes before execution Furthermore an execution success means that the door mechanism has successfully been commanded to open It does not mean that the door opening is completed or confirmed A door motion even
26. Note 8225 COM_SEQ 01 Commissioning Sequences for Alice in Attachment 7 3 2 3 Instrument Checkout and In Flight Calibration 3 2 3 1 In Flight Checkouts Passive Checkouts These tests originally referred to as 6 month instrument checks are intended to allow instruments to perform periodic aliveness checks and functional tests that exercise mechanisms and conduct health checks that do not require specific pointing and can be done with no real time monitoring or special planning They run off the MTL with no parallel operations among different PI instruments and produce minimal science data Typically a total of about 5 days are allotted for passive checkouts of all Rosetta instruments The original plan for A ice 6 month checkouts Commissioning Sequence 13 B consisted of operating the aperture door through 12 open close cycles briefly operating the decontamination heaters for 5 minutes to check that they are still active and acquiring a pixel list exposure with the detector stims turned on to check the functionality of the detector electronics and C amp DH electronics High voltage operation of the detector is not planned for passive checkouts However after commissioning during the in flight planning cycle for the first passive checkout the Alice team decided to omit any activation operations 1 e no HV heaters from all passive checkouts to minimize risks and instead include those operations and other extended
27. PDL turn power on wait for power on event packet F patch specified address lt gt Oxffff issue start 192 24 with config and address parameters wait for power on event packet ENDIF time update load context enable housekeeping OBCP shutdown command safe state wait 10 seconds power off 93 Rosetta ALICE User Manual 6 10 Alice PAD Field Handling For the Rosetta 5 the CCSDS defined PAD field is used as an additional identification for TM packets Rosetta defines solicited data generated in direct response to a TC The PAD field in solicited TM should contain a copy of the PAD field of the requesting TC This functionality only was implemented in the version 2 05 of the Alice software so the instrument will only fully comply with this requirement when executing the version 2 05 code after restart in EEPROM The original versions of the Alice Flight Software version 2 04 as of September 2004 and previous version 2 03 copies the PAD field from a telecommand soliciting a direct response to the TM packet being generated for the following TM packets e TM 6 6 Memory Dump e TM 6 10 Memory Check e TM 17 2 Connection Test Report e TM 18 2 Context Report e TM 20 3 5 Alice Science packet with SID 5 Parameter dump in direct response to the private TC 192 25 Get Parameter File which is handled the same as Get Context This copying EID A 2 7 2 1 page 15 will only ta
28. Page 0 see also EEPromCode status bit 1 Page 1 2 Page 2 3 Page 3 boolean 1 indicates mirror heater power o o o 0 units are detector counts PmCounterlnterval i unsigned 16 stored maximum detector count rate since last report HkHvSet HkMcpVlo HkMcpVhi HkAnodeV unsigned 8 stored anode minimum voltage since last report HkAnodeVhi HkStripl unsigned 8 instantaneous strip current ADC counts unsigned 8 stored minimum strip current since last report HkStriplhi i unsigned 8 mirror primary temperature sensor ADC counts unsigned 8 mirror heater temperature set point ADC counts 8 HkMirrorHtrOn HkGratingHtrOn HkCountRateLo HkCountRateHi HkHvSet HkMepV HkMcepVlo HkAnodev O HkAnodeVlo HkAnodeVhi HkStrip HkStripllo HkStriphi HkMirrorTempPri HkMirrorTempSec HkMirrorHtrSet HkGratingTempPri unsigned 8 grating primary temperature sensor grating secondary temperature sensor III Qo 5 gg 313 ko ko Flo w 3 TIM rating heater temperature set point HkDetDiscr time 48 safety condition dust true safety in effect I I I crI r cr ANIC Iro 5 0 9 lt 70212100 OA 10 0 m c z 0o 20 9 i 2 13111012 5 21315 lz lE 5 5 ko 80 Rose
29. Structure ID mirror heater sensor select 0 1 secondar 5 PmDiscriminator special 8 special 8 85 Rosetta ALICE User Manual 22 PmHvFailMcp MCP voltage max fail count 23 PmHvFailStrip unsigned 8 strip current max fail count aperture door motion timeout kernel clock ticks top bit disables door position sensing updated when door is commanded number of count rate slots for histogram acquisitions pressure trend time margin seconds 10 30 PmTempMask grating 1 1 temperature sensor mask 1 enabled 02masked grating 2 1 mirror 1 1 mirror 2 1 detector body 1 chassis 1 detector electronics 1 C amp DH electronics 1 38 PmSafetyTimeout dust flux safety limit Notes Each hot segment specification masks out detector events in a rectangular area 32 spectral 4 spatial pixels top three bits specify the spatial position of this window remaining 5 bits specify the spectral position of the window 15 PmHvStepSize high voltage step size units DAC counts Telemetry Packet Definition Alice receipt of Multiple Acquire Dump telecommand 192 26 when specified dump is executed and histogram mode data available one dump can consist of up to 19 TM packets Header Information ServiceType 20 1 Service Subtype 3 O Structure ID 11 Packet Length 3994 max data Data Field Information Data Field Remarks SID value 1 McpMaxV MCP high leve
30. actually reached that level Data in the housekeeping packet 3 25 should be used to confirm the actual high voltage level Telecommand Packet Definition Alice Packet Name High voltage off Alice Packet Function turns off high voltage execution always Process ID 12 Service 17 Structure ID 0 data Data Field Information Data Field Telecommand Packet Definition Alice Packet Name Alice Packet Function turns on specified heater Verification Rules acceptance always execution always after confirmation Process ID 12 Service Type 18 Structure ID 2 data Data Field Remarks Heaterld enum 1 heater identifier 0 grating 74 Rosetta ALICE User Manual pt mirror O HeaterSet unsigned 8 heater set point ADC counts Notes critical Telecommand Packet Definition Alice Packet Name Packet Function turns off specified heater execution always Header Information Data Field Information Data Field Heaterld enum 1 heater identifier 0 grating 1 mirror Telecommand Packet Definition Alice Packet Name Detector stimulator on Packet Function turns on the detector stimulator Verification Rules acceptance always Header Information Data Field Information Data Field Remarks Telecommand Packet Definition Alice Packet Name Detector stimulator off Packet Function turns off the detector stimulator Verification Rules acceptance always execution always Header Informat
31. by MEMCTL 5 2 pages 0 15 128K EEPROM writes enabled by MEMCTL 7 1 Note All addresses shown in hexadecimal notation For purposes of the memory management service 4 memory types are defined all with 16 bit access The types and address are as follows e 40 code 0000 7FFF used for dumping checking code memory Rosetta ALICE User Manual e 4 eeprom 0000 FFFF for patching and dumping eeprom organized as four separate code pages e 42 detector 0000 7FFF for direct access to acquisition memory e 43 data 0000 7FFF for access to RAM and I O For performing checksums Alice uses the 8 bit XOR rotate method to enable operation together with the ROSIS The same method is used in the Alice flight release 2 3 4 Data Delivery Concept Application Process IDs APIDs Alice supports three data acquisition modes however as these modes operate exclusively Alice will require only 1 Process ID As allocated in EID A Section 2 8 the value 92 decimal will be used Alice only generates science data when requested by the MultipleAcquireDump telecommand In the dump phase of this command the data is dumped in a burst mode acquired data is transmitted from buffer until buffer is empty Therefore the enable and disable science telecommands service 20 are not meaningful for Alice Alice accepts these two telecommands but they are non functional They return execution success but do not affect science data generation
32. in a loss of science below 1150 but is not fatal to all science Front Aperture Failure to Open Open the aperture door fail safe door to Door accept limited light throughput 5 throughput Detector Failure of Depending on failed component may be electronics component recoverable C amp DH Failure of Depending on failed component may be electronics component recoverable Power Controller Failure of Not recoverable electronics DC DC Converter The following Alice in flight anomalies are listed in the Rosetta document SY CRP 000 Ground Monitoring Recovery Actions Issue 5 2 dated July 17 2006 with the designated appropriate actions necessary see Table 3 3 for the Alice related event list and Table 3 4for the parameter list these are excerpts from the SY CRP 000 Rosetta document Table 3 3 Alice In Flight Monitoring Recovery Event List Table per SY CRP 000 2 gja x E 8 21 J 5 5 5 2 8 X 2 o lt ao 100003 DoorErrorWarningEvent 2 40002 Log as unexpected YALOOO05 ParameterReadWarningEvent 2 40004 Log unexpected daily report 55 Rosetta ALICE User Manual YAL00006 ParameterReadErrorEvent 4 40005 Call engineer 100007 SafetyGroundEvent YAL00008 SafetyOnBoardEvent This event is on the on board event monitoring list service 12 Its recovery action shall be enabled by
33. is generated at the completion of an exposure The resulting data rates for these depend on the specific kind of observations acquisition mode performed the dump selections and in some cases the observed objects Alice data collection consists of a long nominal between 10 seconds and about 30 minutes data acquisition during which no science data is produced followed by a brief period of time during which the acquired Alice data is transmitted dump Alice includes a simple mechanism by which a variable delay can be inserted between packets of a science data dump This parameter is specified for each separate dump operation This allows for a simple control of the maximum output data rate but still the resulting data rate depends on specific science data being dumped actual polling rate and this specified delay First the data dump operation is described initially the simple case is described where the full acquisition buffer is dumped later available selection methods will be described that allow for the optimization of the dumped data with regard to a limited downlink capability For each acquisition up to eight dump selections can be specified that dump selected parts of the acquired data When Alice performs a science data dump some or all of the science data is dumped as one or more science telemetry packets maximum data size 3994 octets each As described above these dumps always happen like a burst at the end of the exposure First w
34. it does not continuously acquire and produce science data in a streaming fashion Rather Alice performs a data acquisition while producing no data then dumps the data in a burst fashion when the acquisition is complete This acquire dump cycle can be commanded by a single telecommand Except for safety monitoring Alice does not perform any operations without being explicitly commanded to do so But the acquire dump command allows for the specification of a number of repetitions of the specified acquire dump cycle and execute for a long period up to 255 65535 seconds 193 days This Multiple Acquire Dump telecommand allows for the commanding of complete science observation sequences with only a single telecommand In addition to and in parallel with science operations housekeeping data can be generated on a selectable periodic basis Telecommands that could potentially cause damage to Alice if used incorrectly or loss of already acquired science data are designated critical Critical telecommands require a two step commanding process where the critical telecommand is followed by a telecommand confirming the critical telecommand If the critical telecommand is not confirmed within a timeout period then it is expired and cannot be executed The critical commanding process is defined to prevent errors when operating Alice in the lab and in flight During mission operations we do not expect that there would be any round trip confirmation of crit
35. model Regularly scheduled use of the EQM is not anticipated but use of the EQM will be requested by the Alice team or ESA as necessary to test new sequences verify revised versions of the Alice flight software and trouble shoot problems and anomalies Figure 6 10 1 Alice Also a Software Test Bed STB is maintained at SwRI to provide additional mission support and software maintenance and testing The STB is similar in configuration to the EQM but does not contain a HVPS However some simple circuitry simulates the read back values from the HVPS The STB also contains a flight identical LVPS and C amp DH and used the spacecraft interface simulator SIS to simulate the spacecraft environment The STB allows for direct measurements on the electronics hardware and easy verification of command sequences However the STB is limited in that the spacecraft environment is simulated The EQM allows for a more precise end to end verification of operational procedures This is a useful tool if special non nominal procedures have to be verified A complete set of spare parts for the EQM and STB will be purchased in 2007 and kept at SwRI Figure 6 10 2 Alice STB 95 Rosetta ALICE User Manual 8 Attachments 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 8 9 Attachment 1 PFM Mechanical Assembly Drawings Attachment 2 Alice Standard Sequences Templates 8225 STD SEQ 01 Rev 0 Chg 4 Attachment 3 PFM Functio
36. packet length valid memory ID one block specified detector memory specification does not cross 16k byte page boundary EEPROM memory specification does not cross 8k byte page boundary and instrument state is checkout execution always Header Information ServiceType fd Service Subtype 5 O Data Field Information enum 8 see notes Notes Memory types Memoryld defined in memory dump telemetry packet 6 6 Only single block packets are supported Multiple dump TM packets may be generated in response 6 6 This telecommand executes in the slow thread only one slow TC ata time Telecommand Packet Definition Alice Packet Name Check Packet Function perform check sum of instrument memory Verification Rules acceptance correct packet length valid memory ID one block specified detector memory specification does not cross 16k byte page boundary EEPROM memory specification does not cross 8k byte page boundary and instrument state is checkout execution always Process ID Service Type 6 i Service Subtype Structure ID 8 data Data Field Information Remarks identifies memory type to check number of memory blocks to check must be 1 memory starting address of this block number of words in block Notes Memory types Memoryld defined in memory dump telemetry packet 6 6 Only single block packets are supported This telecommand executes in the slow thread only one slow TC at a time Teleco
37. second Over a whole day this predicted error accumulates to a clock drift lag of 43 2 seconds per day This drift caused operational problems as the instrument reports earlier times in command acknowledgements and the ground system will report a warning when command acknowledgements are more than 3 seconds before the planned command execution time Version 2 04 flight software In order to correct the clock problem a update for the flight software was developed With respect to the observed clock problem in version 2 03 this version includes two main changes e Clock synchronization is now accepted and processed unconditionally this removes the possibility of ignoring multiple clock synchronization operations during long acquisitions testing showed that this activity does not influence the acquisition operation This will ensure that every 30 minutes the clock is resynchronized irrespective of the ongoing operation e Correction of the incorrect hardware divider factor instead of incrementing the internal clock one for every timer interrupt the clock is now incremented by 1 1 2048 1 00049 After this correction the remaining clock drift was measured on the spacecraft without any synchronization operations a drift value of 0 7 sec day was measured With the 30 minute synchronization period this means that the Alice instrument clock will never drift more than 15 ms from the actual spacecraft time Version 2 05 flight software
38. spectral resolution of 8 12 A FWHM with an IFOV of 0 05 x 2 0 Surrounding the center slit section are the two outer sections with IFOVs of 0 10 x 2 0 and 0 10 x 1 53 A pinhole mask located at the edge of the IFOV of the second outer section provides limited light throughput to the spectrograph for bright point source targets such as hot UV stars that will be used during stellar occultation studies of CG s coma the PSF at the pinhole is larger than the pinhole giving an effective attenuation of 100 3 1 4 Detector and Detector Electronics The imaging photon counting detector located in the spectrograph section utilizes an MCP Z stack that feeds the DDL readout array The input surface of the Z stack is coated with opaque photocathodes of KBr 700 1200 A and CsI 1230 2050 A The detector tube body is a custom design made of a lightweight brazed alumina Kovar structure that is welded to a housing that supports the DDL anode array see Figure 3 1 2 Door Latch Door Spring MgF Window Door Switch Vacuum D wer Chamber Door Release Figure 3 1 2 Left Schematic of the Alice DDL detector vacuum housing Right Photograph of the PFM DDL detector vacuum housing To capture the entire 700 2050 A passband and 6 spatial FOV the size of the detector s active area is 35 mm in the dispersion direction x 20 mm in the spatial dimension with a pixel format of 1024 x 32 pixels The 6 slit height is im
39. state Verification Rules acceptance always execution failure if state change not successful Header Information Process ID Service Type Structure ID Data Field Information Data Field Field Structure Remarks e _ Packet Catego 192 Service Subtype Packet Length data z e N N Telecommand Packet Definition Alice Packet Name Enter checkout state Alice Packet Function cause Alice to enter the checkout operating state Verification Rules acceptance always execution failure if state change not successful Header Information Process ID Service Type Structure ID Data Field Information Data Field Field Structure Remarks pee sj Packet Catego Service Subtype Packet Length data 2 2 0 70 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Confirm critical Packet Function confirms a previously transmitted critical telecommand Verification Rules acceptance correct packet length execution failure if no critical command pending possible critical telecommand timeout expired Header Information Process ID Service Type Structure ID Data Field Information Remarks unsigned 16 bits type and sub type of pending critical telecommand Notes When a critical telecommand is received it is held pending Only one critical telecommand can be pending at any time This confirmation must be received within 30 seconds for a pen
40. the initial mission this information is not required by the Alice instrument as these mechanisms are used to protect Alice from cometary contamination One the spacecraft is operating in the comet vicinity fast reaction to protect the Alice instrument is needed and these data flows are used in that process INFORMATION REQUIRED Instrument Alice I Entit Requirements Rosina Pressure periodic pressure whenever Alice operating Alice required rate is as needed Distribution 19 10 Rosina Pressure Alert one shot pressure alert message when pressure exceeds Alice uses both Rosina data 19 11 Rosina defined value distributions in an identical way required rate applies therefore to combined alert and distribution messages Dust Flux 19 12 periodic dust flux measurement Alice required rate is as needed ee Events INFORMATION OFFERED Alice offers no information 6 9 On Board Control Procedures Alice operations currently use only two OBCPs as documented in Alice Experiment OBCP User Requirements Document RO DSS RS 1023 Issue 1F Date July 22 2002 ON BOARD CONTROL PROCEDURES OBCP SUMMARY instrument OBCP Name Function Usage 1 startup powers up instrument runs patch if needed sets time loads context IN 2 shutdown commands instrument to safe state prior to shutdown NO OBCP Startup This OBCP is used to start A ice Inputs memory configuration Oxff no patch memory address
41. 1 switched from samples after ALICE High OFF to ON Otherwise call Voltage switch on engineer NALDO101 changes from Off to ON NALD0801 Max Anod Voltage ANA V LAL00025 The OOL is expected if it This parameter is occurs while parameter expected for a few NALD0101 switched from samples after ALICE High OFF to ON Otherwise call Voltage switch on engineer NALDO101 changes from Off to ON NALDOB802 Ins Strip ANA LAL00026 Call engineer NALD0901 Min Strip Curr ANA uA LAL00026 Call engineer NALDO902 Max Strip Curr ANA LAL00026 Call engineer Ys NALD1001 Mirror Temp Pri ANA degC LAL00027 Call engineer NALD1002 Mirror Temp Sec ANA degC LALO0027 Call engineer NALD1102 Grating Temp Pri ANA degC LAL00028 Call engineer 1 NALD1201 Grating Temp Sec ANA degC LAL00028 Call engineer NALD1701 Dust Safety DIG 0 LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call Pl and check instrument status 56 Rosetta ALICE User Manual NALD1702 Bright Safety DIG 0 LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call and check instrument status NALD1703 Trend Safety DIG 0 LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call and check instrument status NALD1704 Press Alert Safety DIG 0
42. 3 Event Packet Definitions Detailed description of event packets is included in the Telemetry Packet Definition in Section 6 2 this section provides an overview of the Event packets used by Alice Table 6 1 Event packet summary Event ID Severity Description YALSTOO1 N A Telecommand Acceptance Success YALST002 007 N A Telecommand Acceptance Failure YALST008 N A Telecommand Execution Success YALSTOO9 N A Telecommand Execution Failure YAL00002 Normal Progress Report Aperture door motion event YAL00003 Error Report no action Aperture door motion error event YAL00004 Normal Progress Report Indicate instrument high voltage changed YAL00005 Error Report no action Parameter read warning event YAL00006 Error Report on board Parameter read error event action YAL00007 Error Report ground Safety event YAL00008 Error Report on board YAL00009 Normal Progress Report Power on event YAL00015 Normal Progress Report Acquisition event start cycle YAL00016 Error Report no action Acquisition event safety active start missed 6 4 Anomaly Report Definitions Not Applicable Alice does not output anomaly reports 6 5 Context File Definition The table below lists the 42 bytes of Alice context information and the default values of the parameters The list matches the parameters in the load and store context parameters telecommand service 18 Table 6 2 Paramet
43. 5 The Alice instrument communicates with the OBDH telecommand and telemetry systems via two redundant three signal interfaces per EID A Section 2 7 The clock signal is shared between the telemetry and memory load channels See A ice EID B 2 7 5 for further details 2 5 Flight Data Archive Plan Distribution Plan The Alice data are sent to the Rosetta spacecraft relayed to ground and stored in the ESA Data Disposition System DDS These data can be sent pushed via FTP to computers at the Alice team institution in Boulder Colorado at regular pre defined intervals e g daily and also can be directly requested from the DDS via FTP or web interface The data are passed through instrument team software for calibration and analysis These pipeline programs can be run interactively but typically will be called by a UNIX shell script as the DDS regularly pushes A ice data The Rosetta Alice data processing software consists of two parts 1 Collection Programs to read in the files containing the spacecraft data packets as obtained from the DDS and combine them into self contained and complete data files This 15 performed by a C program called LIMA 2 Calibration Programs to process and calibrate the science data Steps include flat fielding deadtime correction and applying wavelength and flux calibration This is performed by a set of IDL programs called MIKE For more details of the calibration programs and the pipeline s
44. 51 3 2 6 Operational Constraints sker e e tee petiere ER 51 3 3 FAILURE DETECTION AND RECOVERY STRATEGY er seen brer 55 225 58 4 1 MODE TRANSITION TABLE 5 A nter e b eH ddr 58 4 2 DETAILED MODE DESCRIPTIONS 531 rH Here eb dr ede e let reed 59 OPERATIONAL PROCEDURES DRD 51 2 59 5 1 GROUND TEST SEQUENGES sats evene tie veta e o er 59 5 2 ON BOARD CONTROL PROCEDURES ss sssoreeeseseseressesereressrrereresrrrrerrrserer er rr 61 5 3 FLIGHT CONTROL PROCEDURES ssssroreessrrerereseseressoserereserrerereserrrrrrrserer er rese rr esse ser ers AR er EES RAR ERE RAR KR REAR er ene or arena 61 5 4 CONTINGENCY RECOVERY PROCEDURES EID B 96 5 4 2 0 000000000000000000000000000000 000 nennen nnns 61 DATA OPERATIONS HANDBOOK DRD 65 2 2 65 6 1 TELECOMMAND PACKET AND PARAMETER DEFINITIONS eese 66 6 2 TELEMETRY PACKET AND PARAMETER 8 2 22 02 020000 eene net 78 6 3 BVENT PACKET DEEINITIONSu 6 nente iti ar 90 6 4 ANOMALY REPORT 5 6 30 x e AS IEEE or EUREN ERE EO 90 6 5 CONTEX
45. 64 93030 10 42 57 4 64 23 40 2 76 BOVp The Car 49933 05435 12 08 21 5 50 43 21 2 60 B2IVne Del 21308 06490 12 15 08 7 58 44 56 2 80 B2IV Del Cru 17723 08248 12 26 35 9 63 05 57 1 33 0 51 AlpicCru 186378 08249 12 26 36 5 63 05 58 1 73 B1V Alp2Cru 90356 09668 12 37 11 0 69 08 08 2 69 B2IV V 1 Mus 19613 11123 12 47 43 2 59 41 19 125r BO SLII Bet Cru 200629 l6658 71132 25 11 6 11 09 41 0 98 B1III IV B2V 67Alp Vir 180284 18716 133395352 53227 59 2 30 Eps Cen 53451 20315 13 47 32 4 49 18 48 1 86 B3V 85Eta UMa 29665 21263 13 55 32 4 47 17 18 2 595 B2 5917 Zet Cen 22313 22451 14 03 49 4 60 22 23 0 61 Bet 253488 27972 14 35 30 4 42 09 28 2 31 B1 5Vne Eta 52961 29056 14 41 55 8 47 23 18 2 30 B1 5III Vn Alp Lup 53451 107 Rosetta ALICE User Manual 132058 14 58 31 9 43 08 02 2 68 B2III IV Bet Lup 19 95 136298 15 24 22 32 40238 51 3222 Del Lup 22906 138690 15 35 08 5 41 10 01 2 78 B2IV Gam Lup 18053 143018 15 58 51 1 26 06 51 2 89 BI1V B2V 6Pi Sco 31042 143275 16 00520 0 5 22237218 2 32 0 3 7Del Sco 74884 144217 16 05 26 2 19 48 20 2 62 8Bet1Sco 39806 127165 T6220 211 3 25 35 34 2489 20Sig Sco 31042 148478 16 29 24 4 26 25 55 0 96 M1 5Iab Ib B4Ve 21Alp Sco 44297 149438 16 35 53 0 28 12 58 2 82 BOV 23Tau Sco 47249 149757 16 37 09 5 10 34 02 2 56 09 5Vn 13Zet Oph 79859 5890 16251252 2 302 51 3 08 B1 5V
46. ATOR LAT MOTOR TA 000643 Figure 2 2 1 The Alice power system Electrical interface circuits used by the Alice instrument consist of the following types of interfaces e Operating 28 V power interface prime and redundant Includes the heater power and the door actuation power e Operating power return prime and redundant e Chassis ground The Alice instrument provides a diode or circuit to generate a single operational 28 V supply that is then filtered and distributed to the instrument through an isolated DC DC converter which generates 5V and 5V and that runs at a nominal frequency of 550 kHz A high voltage power supply HVPS with outputs from 0 kV to 6 5 kV 15 supplied from the 5 and 5V supplies The characteristics of this interface are summarized in Table 2 2 14 Rosetta ALICE User Manual Table 2 2 Operational Power Interface Characteristics INTERFACE DESIGNATION PRIMARY INSTRUMENT POWER Maximum Average Input Current 28V Normal Full Instrument Operation 0 129 0 143A Decontamination Operations Occasionally 0 143A 0 214A nominal lt 1 hr but up throughout mission to 24 hr during commissioning Daily multiples Instrument Door Actuation 0 329A 0 343A 2 second maximum Inrush Characteristics Peak current 25V Assuming 35 overshoot 0 8A Current at t 8 ms 0 129 A GUERRA Secondary return to chassis when single 0 Mohm point ground attachment is removed EMI Characteris
47. ENT 7 Commissioning Sequences for Alice 8225 COM SEQ 01 103 Rosetta ALICE User Manual ATTACHMENT 8 Test Sequence Definitions for Alice System Validation Test 8225 SVT_DEF 01 104 Rosetta ALICE User Manual ATTACHMENT 9 Alice RSDB Summary 8225 RSDB SUM 01 105 Rosetta ALICE User Manual ATTACHMENT 10 Alice EMI Waiver RO ALI RW 009 106 Rosetta ALICE User Manual ATTACHMENT 11 Alice Hot UV Star List Bad Dogs Version Date 2006 September 26 This list of Dog stars stars that create too high of a count rate on the Alice detector was created using model predictions based on data from the Yale Bright Star Catalog and Kurucz model stellar fluxes An updated version of this list is in progress using actual International Ultraviolet Explorer IUE UV spectra with Kurucz models to more accurately determine the true stellar flux For this current list the expected Alice count rates are predicted by convolving the Alice sensitivity curve effective area over the wavelength range 700 2080 A with Kurucz models that are normalized to Vega s IUE flux at 1500 A of F iue vega 6 40924e 09 erg s cm 2 using the Kurucs model Vega V 39 2561 mag and normalizing to the residual V magnitude difference of each star The following tables are for stars that produce more than 15 000 counts sec based on these calculations It is sorted by HD number equivalent to sorting by RA Yale Bright Star Catalog
48. LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call and check instrument status NALD1705 5 Safety DIG 0 LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call and check instrument status NALD1706 Temp Safety DIG 0 LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call Pl and check instrument status NALD1707 Safety Override DIG 0 LAL00031 Call engineer NALD1708 Dust Mask DIG 0 LAL00032 Call engineer NALD1709 Bright Mask DIG 0 LAL00032 Call engineer NALD1710 Trend Mask DIG 0 LAL00032 Call engineer NALD1711 Press Alert Mask DIG 0 LAL00032 Call engineer NALD1712 5 Mask DIG 0 LAL00032 Call engineer NALD1713 Temp Mask DIG 0 LAL00032 Call engineer NALD1801 Det Elec Temp ANA degC LAL00033 Call engineer NALD1802 Det Housing Temp ANA degC LAL00034 Call engineer NALD1901 C amp DH Elec Temp ANA degC LAL00035 Call engineer NALD1902 Instr Hous Temp ANA degC LAL00036 Call engineer NALD2002 Major SW Version NONE 0 LAL00038 Call engineer NALD2003 Minor SW Version LAL00039 Call engineer NALD3704 NALD3705 NALD3706 Trend Safety Press Alert Safety HVPS Safety DIG LAL00030 LAL00030 LAL00030 investigation Call engineer for investigation Call engineer for investigation Call engineer for investigation
49. MITER SNR 96 8 7 ATTACHMENT 7 COMMISSIONING SEQUENCES FOR ALICE 8225 COM 01 96 8 8 ATTACHMENT 8 TEST SEQUENCE DEFINITIONS FOR ALICE SYSTEM VALIDATION TEST 8225 SVT_DEF 01 96 8 9 ATTACHMENT 9 ALICE RSDB SUMMARY 8225 5 2 96 8 10 ATTACHMENT 10 ALICE EMI WAIVER 009 96 811 ATTACHMENT 11 ALICE HOT UV 5 1 57 0022 2 2 2 0 01 00000 000000000000 96 8 12 ATTACHMENT 12 ALICE IN FLIGHT APERTURE DOOR PERFORMANCE 6 0400 0000 96 LIST OF FIGURES Figure 1 3 1 The opto mechanical layout of Alice eese ene rn on 11 Figure 1 3 2 External view of Ale treten e i e E 12 Figure 1 3 3 Photograph of the Alice protoflight model with the top cover removed 12 Figure 1 3 4 Block diagram of Alice sossessssssserssresrsrsresrerrrsresrerresrerrrsresrerrrsr nennen nennen enne en 12 Figure 2 2 T Alice power System e ep etse ne Ere de ste er ng dr ST 14 iii Figure 2 2 2 Alice telecommand interface circuit essere nennen ren 17 Figure 2 2 3 Alice telemetry interface circuit eene nennen nennen enne sr ene rn on 17 Alice MEMOry MAP ss esce net o EIE RI EEG 21 Figure 2 3 2 The Alice software operating state
50. Maps ic EU DEA EE RE UU 21 Figure 2 3 2 The Alice software operating state 27 Figure 3 1 1 The Alice entrance slit design a The physical dimensions of the slit b The slit orientation with respect to the DDL detector image spatial axis and the spacecraft axes 35 Figure 3 1 2 Left Schematic of the Alice DDL detector vacuum housing Right Photograph of the DDL detector vacuum housing s ssesssssressrerrrssrrssrrssresrresrresrrsr eene en nenne RR RR rer rn nn 36 Figure 3 1 3 The Alice electrical block diagram essemsssssssrserserresrerrrsresrerrrsresrerrrsrerrrsr ere nennen nennen 38 Figure 4 1 1 The Alice top level mode transitions sr ene rn enn 58 Figure 6 10 1 Alice soon unu mane une 95 Figure 6 10 2 Alice Rae e tee ree ree eene teen eed ited tee n re e tete 95 iv DOCUMENTATION CHANGE RECORD Ver Rev Section Date Changes 1 0 2 23 00 First Draft Issue 1 1 10 16 00 Rev 1 Issue 1 2 05 10 01 Rev 2 Draft Issue 1 2 All 5 16 01 Rev 2 Issue 1 3 7 5 02 Rev 3 Issue 3 2 1 Minor wording changes in description of detector tests 3 2 2 Referenced new Commissioning Plan document 6 7 Added attachment 7 Commissioning Sequences 1 3 2 2 7 20 02 Filled in TBDs in Table 2 2 2 EMI Char
51. NALD3702 Dust Safety LAL00030 Call engineer for ALICE has entered unsafe investigation conditions First action call Pl and check instrument status NALD3703 Bright Safety LALO0030 Call engineer for ALICE has entered unsafe conditions First action call and check instrument status ALICE has entered unsafe conditions First action call PI and check instrument status ALICE has entered unsafe conditions First action call PI and check instrument status ALICE has entered unsafe conditions First action call Pl and check instrument status NALD3707 NDMWO21A Temp Safety Auto WOL Status DIG LAL00030 LDMX0012 57 Call engineer for investigation An OOL on this parameter is expected after a safe mode and when the Auto WOL function is re enabled by ground command AC FCP 125 In all cases where this parameter becomes out of limit check that ROSINA ALICE and RPC are switched off If one of the PL is active call engineer ALICE has entered unsafe conditions First action call Pl and check instrument status Rosetta ALICE User Manual NPWDA570 ALICE PS1 PLCL 11A CUR ANA A LPW03140 Call engineer Parameter on DMS monitoring list service 12 Monitoring status controlled by ALICE switch ON procedure Recovery action start ALICE OFF OBCP OBCP 8012 NPWDA578 SPARE PLCL 12A CUR ANA A LPW03141 Call engine
52. Process IDs APIDs sss 22 2 3 5 dining Requirements vs s ud s Sav o 22 2 3 6 BOOESCQUCNCE S Led io NR reae euis t tee E P 24 2 3 7 Instrument Operating Modes esteen ensei e entente rene etre reir 25 2 4 BUDGETS ORD 12 eee epe ere irre pest 28 2 4 1 MASS ites efi 28 2 4 2 Operating Power Alice EID B 2 4 3 28 2 4 3 Data Rates Housekeeping and sse een 28 2 4 4 Non Operating Heaters Alice EID B 2 3 3 2 33 2 4 5 S C Powered Thermistors Alice EID B 2 3 3 4 33 2 4 6 Pyro Lines Alice EIDZB 8 29 r e decente et p t xr t ERES eere iode OE br OR a ho aaan 33 2 4 7 OBDH Channels Alice EID B 2 7 5 isses dets enne eene 33 2 5 FLIGHT DATA ARCHIVE PLAN DISTRIBUTION PLAN e een een en en nen ener enne 33 3 EXPERIMENT OPERATIONS v vsves osssssvsssossesessurossuussosvosossosusnessonesesessenssssssrrensesessssnssdensevenstonssvsnestenesnesessensees 34 XT OPERATING PRINCIPLES sis e tirer viro rare i e a HE ao e erdt spe e dess NN gre AT Rer 34 3 1 1 Instrument Overview aa pete bte Ep br obe Ee eE 34 3 1 2 Optical Design scc
53. T EIEE 5 UE e 90 6 6 DATA AND DUMPEIEEDEFINPEIONS tr REG OR Ste 92 6 7 SSMM UTILIZATION 8 eei ttes eser ee te tbe Len a ve tede de add 92 6 8 INFORMATION DISTRIBUTION REQUIREMENTS nane eterna 93 6 9 ON BOARD CONTROL PROCEDURES eue ceeds ree d 93 610 ALICEPAD FIELD HANDLING t pr Hr re teet e aree at desit 94 ROSETTA ALICE AND STB CONFIGURATION AND USE eee 95 ATTACHMENTS MT iia 96 8 1 ATTACHMENT 1 MECHANICAL ASSEMBLY DRAWINGS ssseeserssreresssesersrserserererersrrrressrrerererrrr nennen enne 96 8 2 ATTACHMENT 2 ALICE STANDARD SEQUENCES TEMPLATES 8225 STD SEQ 01 REV 0 CHG 4 96 8 3 ATTACHMENT 3 PFM FUNCTIONAL TEST PROCEDURE 8225 FTP 01 REV 2 sese 96 8 4 ATTACHMENT 4 TEST SEQUENCE DEFINITIONS FOR ALICE FLIGHT SOFTWARE 8225 TEST DEF 01 REV mE Tharsis Mees 96 8 5 ATTACHMENT 5 ALICE END TO END RADIOMETRIC TEST S C VERSION 8225 ETE RAD SC 01 96 8 6 ATTACHMENT 6 ALICE DETECTOR VACUUM PUMPDOWN amp BACKFILL PROCEDURE 8225 DET PUMPDOWNG O TL EE eet ER Eee S
54. TION 0 senses sts ta 9 rr QUERI pne EO TA NO 9 1 2 SCIENTIFIC OBJECTIVES ALICE EID B 1 1 1 9 1 3 4 EXPERIMENT OVERVIEW i E rede ie E dr i edt e Fr 10 2 EXPERIMENT CONFIGURATION eerie eese tns tussis 13 Dil PHYSICAL pcd aeo 13 2 2 ELECTRICAL codec O UE EH GO rei n rana d ur nere ak ee o v 13 2 2 1 Power Interface Circuits Alice EID B 2 4 enne 13 2 2 2 Pyrotechnic Interface Circuits Alice EID B 2 5 sss eene nennen ens 15 2 2 3 OBDH Interface Circuits Alice EID B 16 2 2 4 Instrument Heaters ed eee 18 2 2 5 Instrument Thermistors Housekeeping Sensors essen eene eene 18 2 3 SOPTWARE DRD 28 L A RR HO ES a FU ev ete Oe BERE VERSER 18 2 3 1 Software OVERVIEW ss cette ttt ve den ul teda tet pute en Ete edet eec bete 18 2 3 2 Autonomy CONCEPE st bo tr ent ote pede bus 19 2 3 3 Software Maintenance Approach utet ot bea et Pee i ertt eet desde edet bet 20 2 3 4 Data Delivery Concept Application
55. V OPERATIONS HV HV 1 Initial Turn On Requirements i At least 30 days shall have elapsed since launch ii ROSINA shall measure a spacecraft pressure 10 millibars 7 5 x 10 Torr iii The aperture door shall be open Note If the aperture door is failed closed a failsafe door open turn on may be considered iv gt 24 hours of decontamination heating of the OAP and grating shall have been performed v Alice shall be pointed to a safe attitude vi Alice shall have all 8 measured temperatures within their nominal operating range and acceptable to the Project Manager vii HV turn on shall be a critical command 1 must be followed by a confirm critical command viii Initial turn on shall require a real time light delayed link and a slow HV ramp up HV 2 General Turn On Requirements i ROSINA shall measure a spacecraft pressure 10 millibars 7 5 x 10 Torr ii All instrument read thermistors must be within the range from 35 to 60 C iii If either the Aperture Door or Fail safe Door is open A ice shall be pointed in a safe direction iv HV turn on shall be a critical command 1 must be followed by a confirm critical command HV 3 Shutdown conditions i ROSINA pressure above 10 millibars ii GIADA dust alert gt 30 counts m min HV 4 S C slew operations Unless otherwise stated by the Alice team e g except for slews designed for Alice science operations during
56. a Alice engineering memorandums Optics Decontamination During the commissioning phase of the flight and during the instrument checkout phases prior to science target encounters the Alice optics will require heating to drive off contaminants that have collected on their respective surfaces Each optical element i e the OAP mirror and grating is equipped with a 1 Watt resistive heater Each optic is also equipped with redundant thermistors The Alice C amp DH electronics will be responsible for control and monitoring of the decontamination heaters and thermistors It should be noted that the Alice instrument will need to be in a near full power up mode before turning on the decontamination heaters i e C amp DH electronics detector electronics and HVPS will all be on except for the initial decontamination sessions prior to the opening of the detector door This is necessary for 1 control and monitoring of the decontamination activity and 2 to provide joule heating to the detector MCP Z stack to prevent constituents off gassed from the optics from collecting on the sensitive detector surface Note that in subsequent operations the HV is not applied to the detector for decontaminations it was decided that the joule heating was not significant and running HV for long decontaminations was not necessary Aperture Door Opening During the initial turn on and checkout of Alice Commissioning Phase I see Attachment 7 the Alice front aperture door
57. a row followed by a 5 minute wait period resulting in a total execution time of almost an hour Here the results of 36 cycles were obtained and the average numbers seem to be very much in line with the earlier measurements 9 28 2004 Start movement End movement Door open 18 4 ms 69 7 ms Door close 16 9 ms 75 1 ms Further inspection of this data though showed a surprising rising trend in the end door close times This test was performed after the instrument had been on for 3 hours for a decontamination procedure and measured temperatures during this test are nearly constant Also note that in between these two door measurement activities the door was operated more than 300 cycles during the interference test Further investigation of the results did not result an explanation Even though the actual movement itself is still very quick the clear trend is a reason for concern and further evaluation will be needed FM Doorlife measurement 9 28 2004 122 poo g N ee e open start m open end close start close end w 2 I 3 measurement cycle AS part of the investigation into the observed trends a similar measurement was performed on the Software Test Bed STB The STB includes a door simulator that consists of an identical motor and two 109 Rosetta ALICE User Manual optical switches The mechanical construction is differen
58. acteristics 3 1 7 26 02 Rev 3 Modifications post EFOR meeting 3 2 2 Minor changes to Section 3 1 3 2 3 Reference to Commissioning Plan in Section 3 2 2 3 4 Reference to Commissioning Plan in Section 3 2 3 4 1 Added new Section 3 4 Operational Constraints 5 1 Added descriptive text to Section 4 1 5 3 Added description of MST Section 5 1 5 4 Reference to Commissioning Plan in Section 5 3 6 9 Additional details added to Section 5 4 including subsection on 7 2 5 detected out of limits 7 7 Added new Section 6 9 Alice PAD Field Handling 7 8 Added new updated documents to Attachments 2 On Board 7 9 Software amp Autonomous Functions 7 Commissioning 7 10 Sequences for Alice 8 Test Sequence Definitions for Alice System Validation Test 9 Alice RSDB Summary and 10 Copy of EMI Waiver RO ALI RW 009 1 4 1 1 11 2003 Updated with new target comet 67P CG 2 2 1 Removed TBRs in Figure 2 2 2 2 3 Added reference to the Alice Ground Software 2 4 Added section describing the flight data archive plan 2 5 2 Updated the Alice Power Consumption table 2 5 1 3 1 3 Updated Aliveness Functional Tests text 3 1 4 Added section Code Memory Management 3 1 5 Added section Software Code Patch Operation 3 1 6 Updated Optical Alignment Check text 3 1 11 Added section Fail Safe Activation 5 4 Removed TBD of heater temperature sensor disagreement 5 4 Removed TBD in S C Detected Out of Limits added Table 5 4
59. actual A ice data files FITS and ASCII files but only create PDS conforming label files that describe the Alice data files Reference documents e Rosetta Archive Generation Validation and Transfer Plan RO EST PL 5011 e Rosetta Alice to Planetary Science Archive Interface Control Document 8225 EAICD 01 3 Experiment Operations 3 1 Operating Principles 3 1 1 Instrument Overview An opto mechanical layout of Alice is shown in Figure 1 3 1 Light enters the telescope section through a 40 x 40 mm entrance aperture at the bottom right of Figure 1 3 1 and is collected and focused by an f 3 off axis paraboloidal OAP mirror onto the entrance slit and then onto a toroidal holographic grating where it is dispersed onto a microchannel plate MCP detector that uses a double delay line DDL readout scheme The two dimensional 1024 x 32 pixel format MCP detector uses dual side by side solar blind photocathodes potassium bromide KBr for X lt 1200 A and cesium iodide CsI for X gt 1230 A The measured spectral resolving power A AA of Alice is in the range of 70 170 for an extended source that fills the instantaneous field of view IFOV defined by the size of the entrance slit Alice is controlled by a Sandia Associates 3865 microprocessor and utilizes lightweight compact surface mount electronics to support the science detector as well as the instrument support and interface electronics Figure 2 shows both a 3D external view
60. aged onto the central 20 of the detector s 32 spatial channels the 36 Rosetta ALICE User Manual remaining spatial channels are used for dark count monitoring Our pixel format allows Nyquist sampling with a spectral resolution of 3 4 and a Nyquist sampled spatial resolution of 0 62 The MCP Z Stack is composed of three 80 1 length to diameter L D MCPs that are all cylindrically curved with a radius of curvature of 75 mm to match the Rowland circle for optimum focus across the full spectral passband The total Z Stack resistance at room temperature is 500 MQ The MCPs are rectangular in format 46 x 30 mm with 12 um diameter pores on 15 um centers Above the MCP Z Stack is a repeller grid that is biased 1000 volts more negative than the top of the MCP Z Stack This repeller grid reflects electrons liberated in the interstitial regions of the MCP back down to the MCP input surface to enhance the detective quantum efficiency of the detector The expected H I Lyman a 1216 A emission brightness from comet 67P CG is 4 kR ata heliocentric distance of 1 3 AU based on IUE observations of this comet in 1982 To prevent saturation of the detector electronics it is necessary to attenuate the Lyman a emission brightness to an acceptable count rate level well below the maximum count rate capability of the electronics i e below 10 c 7 An attenuation factor of at least an order of magnitude is required to achieve this lower count ra
61. al view of Alice F igure 1 3 3 Photograph of the Alice protoflight model with the top cover removed S C Power S C TM TC Interface Interface Photons DDL Detector Decontam Heaters Detector C amp DH Electronics Electronics Actuators Figure 1 3 4 Block diagram of Alice 12 Rosetta ALICE User Manual 2 Experiment Configuration 2 1 Physical The Alice mechanical interface drawings MICDs for the Protoflight Model are shown in Attachment 1 2 2 Electrical 2 2 1 Power Interface Circuits Alice EID B 2 4 The Alice instrument derives operating power from an isolated dual output DC DC converter and a single high voltage power supply A common filter module for incoming spacecraft power is used to both protect the instrument from transients and to filter instrument generated noise from coupling to other spacecraft systems Figure 2 2 1 illustrates the number and type of power input lines with returns used by Alice Table 2 1 lists these lines Table 2 1 Power Supply Interface Requirements Number of Number of Function Main Lines Redundant Lines LCL Class Required Required 28 V MAIN BUS Switched and Current 1 1 limited Decontamination Nonops Heater Keep Alive Supply 13 Rosetta ALICE User Manual 28 V RETURN PRIME TO 28 V REDUNDAN INSTRUMENT 28 V RETURN REDUNDANT FROM CONTROL ELECTRONICS ELECTRONICS INSTRUMENT DOOR ACTU
62. an when one or multiple dumps have been specified the science data packets will be when instrument is not acquiring and not dumping this occurs before and after execution of a MAD command but it can also occur when a cycle time has been 58 Rosetta ALICE User Manual specified that is larger then the combined acquire and dump time the remainder of the time will be spent in this state The MAD command will either end in the Hold state when the MAD command has completed normally or Safe when the MAD command was terminated because of a safety condition In all the above instrument states Acquire Dump and Standby the power draw is specified in Table 2 12 for Mode 1 when the HVPS is not at full operational level and for Mode 2 when the HVPS is fully activated at the operational HV level The power in Mode 3 of Table 2 12 only occurs when the optical heater elements are also engaged and operating during optical decontamination sessions see Section 2 2 4 When Alice is acquiring science data and receives an Enter Safe State telecommand only the current acquisition cycle is terminated This means that ifa MAD command specified multiple acquisition cycles the acquisition will re start when the next cycle is due To terminate a MAD command the Stop Acquisition telecommand has to be used This command will cause the A ice instrument to terminate the completed acquisition command and return to the Safe state In this case the MAD comm
63. and returns an Execution failure state and the Stop acquisition command will return an Execution success status both when requested 4 2 Detailed Mode Descriptions See Section 2 3 7 5 Operational Procedures DRD 51 2 5 1 Ground Test Sequences The Alice ground test sequences are summarized below Detailed procedures for each test sequence are referenced in Table 5 1 the Alice electrical functional tests are run with the Alice HVPS set at 0 volts with the Alice HV safing plug installed or at a low level of 250 V with the HV safing plug removed An Alice team member must be on site during A ice ground tests whenever the HV safing plug is removed This is also applicable to all the SPT tests see below that require commanding the Alice HVPS to its full operational level 4 kV Bench Test BT The Alice BT shall verify the electrical functionality of the Alice instrument excluding operation of the detector HVPS to its full operational HV level 4 kV Instead the HVPS will be commanded to a low HV setting of 250 V the detector can be safely operated at this low HV level while backfilled at 1 atm GN This test will be performed at delivery to the S C contractor Alenia with Alice on the bench in a suitable clean room environment The BT will consist of the Alice Full Functional Test procedure 8225 FTP 01 see attachment 3 An SPT see below will also be conducted during the Alice BT The FFT and SPT tests must onl
64. arameters defined integration time duration of acquisition in time or events e aperture door open closed detector stim on off e clear memory at the start of the acquisition These parameters determine how long the acquisition runs until it is complete and also control the behaviour of the instrument door and detector stimulation while the acquisition is in progress The clear memory parameter determines if the acquisition memory is erased before the acquisition is started The dump function may specify up to 8 different dump windows to be transmitted after completion of the acquire function Each specified dump window has the following parameters filter window 30 Rosetta ALICE User Manual collapse factors These parameters do not apply to all modes of data The filter window is applied to histogram or pixel list data Only detector events that occur within the specified window will be included in the data dump This provides a means of looking at only a particular area of interest on the detector thus reducing the amount of data sent in telemetry The collapse factors are applied only to the histogram data The acquired data is binned in spatial and spectral dimensions according to the collapse factors Again this allows a means of reducing the volume of science data that must be sent via telemetry To limit the number of telecommands needed for nominal A ice science operations the MAD telecommand allows for the
65. ata system 3 2 4 7 Targets of Opportunity Targets of Opportunity e g a nearby comet or coordination with another mission such as Deep Impact comet Tempel 1 and New Horizons Jupiter may arise during any phase of the mission and operations for these events will be uniquely defined by the target viewing conditions etc If Alice participates in the observations of such targets operations again will typically include the standard suite of operations Similarly during any flyby or comet phase stellar occultations may take place that we would want to observe with Alice With the target star in the Alice slit during the occultation period observations will typically be made in pixel list mode to provide time resolution during occultations Additional calibration observations will be made of the target star long before or after the occultation event to provide a clean spectrum for comparative analysis these spectra will typically be made with long histogram mode exposures to obtain high S N 3 2 5 Interferences There are no known interferences other than those listed in the Flight Operational Constraints Section 3 2 6 that limit the performance of Alice on the Rosetta spacecraft During initial interference tests performed in September 2004 no interferences were seen in A ice data due to other instruments and none due to A ice were reported by other instruments However those interference tests were not fully inclusive of al
66. ations pointed or scanning observations etc and depend on the details such as flyby geometry constraints that may be imposed by the spacecraft or other instruments and the status of Alice Below we provide general outlines of the high level operations that at this time are expected to be used in each type of mission phase Most operations will typically include power up tests decontaminations calibrations and observations in any or all of the Alice acquisition modes See Attachment 2 Document 8225 STD SEQ 01 Alice Standard Sequences Templates for the list of sequences available for standard Alice operations 49 Rosetta ALICE User Manual 3 2 4 1 Commissioning Commissioning includes instrument validation and testing calibration alignment sensitivity wavelength interference tests initial testing of operational procedures of the Alice instrument and of the interfaces instrument to spacecraft spacecraft to ground DDS to PI institution PI to RSOC See Attachment 7 Technical Note 8225 COM_SEQ 01 Commissioning Sequences for Alice and Section 3 2 2 for sequences and operations used uniquely for the commissioning phases during the first year after launch Many of the sequences therein have been subsequently removed from the FOP since they are no longer applicable after completion of commissioning 3 2 4 2 Cruise The several cruise phases will typically include passive and active Payload Checkouts PCs which are desc
67. bserved gases Mapping the time variability of O and possibly 5 and emissions in the coma and ion tail in order to connect nuclear activity to changes in tail morphology and structure and tail interaction coupling to the solar wind Table 1 1 Approximate Alice Characteristics and Performance Overview Passband 700 2050 A Spectral Resolution 8 12 A extended source AX FWHM 4 9 A point source Spatial Resolution 0 05 x 0 6 Nyquist Effective Area 0 02 1575 0 05 cm 1125 Field of View 0 05 x 2 0 0 1 x 2 0 0 1 x 1 5 Pointing Boresight with OSIRIS VIRTIS Nucleus Imaging and Spectroscopy Coma Spectroscopy Observation Ty pes Jet and Grain Spectrophotometry Stellar Occultations secondary observations Telescope Spectrograph Off axis telescope 0 15 m diameter Rowland circle spectrograph Detector Type 2 D Microchannel Plate with double delay line anode readout 1 3 Experiment Overview The Alice UV spectrometer is a very simple instrument An opto mechanical layout of the instrument is shown in Figure 1 3 1 Light enters the telescope section through a 40 x 40 mm entrance aperture and is collected and focused by an f 3 off axis paraboloidal OAP primary mirror onto the approximately 10 Rosetta ALICE User Manual 0 19 6 spectrograph entrance slit see below for a description of the entrance slit geometry After passing through e
68. ch level functional testing Alice will be stimulated with a UV emitting platinum neon Pt Ne hollow cathode lamp that emits UV light at wavelengths gt 1200 A This lamp will be mounted in close proximity to the MgF window port on Alice s internal front aperture cover Wavelengths down to the MgF window cutoff 1200 A will transmit through the instrument as long as the instrument is filled with GN The length of this Pt Ne stim lamp will not exceed 30 cm With the detector vacuum cover closed and the internal detector tube body pressure lt 8 x 10 Torr it is safe to operate the detector at the full operational high voltage level 4 KV The UV emission lines from the Pt Ne lamp will stimulate the detector across a portion of its active area During spacecraft level integration the Alice instrument can be turned on and tested end to end at time the GSE ion pump is attached to the instrument and detector vacuum is verified by noting the ion pump current Because of the logistics problem no detector HV tests will be performed during spacecraft thermal vacuum T V testing because of the difficulty and cost of providing a UV source that can be operated in vacuum The Alice detector will however be evacuated using the Alice MGSE vacuum pump station prior to the T V test following the test the detector will be backfilled with GN To keep the interior optics grating and OAP primary mirror clean and dry Alice will require co
69. ch the end position reaches the door open switch The same measurements are performed during the following door close move resulting in four measurements per door cycle The results of these measurements are stored in a special buffer that is located at a fixed location in the processor RAM area starting at word address 0x5b00 This buffer is used as a circular storage and can hold up to 64 one word time values size is 128 bytes Each door measurement results in 4 measurement cycles so the buffer can store up to 16 complete measurements To retrieve the data from the buffer the standard available memory dump command has to be used This aperture door performance test is performed with the Alice command sequence AALS404A That sequence first restarts Alice in a user defined EEPROM page then calls the subroutine by executing 43 Rosetta ALICE User Manual the address where the code resides sixteen times typical test consists of 30 to 40 flaps i e two calls to AASL404A Attachment 12 describes the latest results of the in flight door performance tests As of September 2006 the Alice aperture door has cycled open close 639 times 3 1 12 Fail Safe Door Activation If the front aperture door fails to open during any phase of the flight a one time openable fail safe door can be activated that allows 5 of the airglow aperture throughput into the instrument The fail safe door is held in the closed state via a latch pin that
70. clude preamplifier circuitry time to digital converter circuitry TDC and pulse pair analyzer charge analysis circuitry PPA All of these electronics are packaged into three 64 x 76 mm boards These three boards are mounted inside a separate enclosed magnesium housing that mounts to the rear of the spectrograph section just behind the detector vacuum chamber The detector electronics require 5 VDC and draw 1 1 W The detector electronics amplify and convert the detected output pulses from the MCP Z Stack to pixel address locations Only those analog pulses output from the MCP that have amplitudes above a set threshold level are processed and converted to pixel address locations For each detected and processed event a 10 bit x address and a 5 bit address are generated by the detector electronics and sent to the Alice command and data handling C amp DH electronics for data storage and manipulation In addition to the pixel address words the detector electronics also digitizes the analog amplitude of each detected event output by the preamplifiers and sends this data to the C amp DH electronics Histogramming this pulse height data creates a pulse height distribution function that is used to monitor the health and status of the detector during operation A built in stim pulser is also included in the electronics that simulates photon events in two pixel locations on the array the rightmost highest X value stim falls partiall
71. ding critical telecommand Packet Catego Service Subtype Packet Length data z 2le SoN Alice Packet Function Ss mone Header Information Process ID Packet Category Service Type Structure ID Notes Telecommand deleted after addition of the Multiple Acquire Dump telecommand 192 26 Alice Packet Function none Process ID Packet Category Service Type Structure ID Notes Telecommand deleted after addition of the Multiple Acquire Dump telecommand 192 26 Alice Packet Function none Process ID Packet Catego Service Type Structure ID Notes Telecommand deleted after addition of the Multiple Acquire Dump telecommand 192 26 Telecommand Packet Definition Alice Packet Name Alice Packet Function cause Alice to stop Multiple Acquire Dump in progress Verification Rules acceptance always execution always Header Information Process ID Packet Catego Service Type Structure ID data Data Field Notes This telecommand does not have any effect when no Multiple Acquire Dump command is in progress zs Rosetta ALICE User Manual Alice Packet Function none 9 2 Process ID Packet Category Service Type Structure ID Notes Telecommand deleted after addition of the Multiple Acquire Dump telecommand 192 26 Alice Header Information Process ID 92 Packet Catego Service Type Structure ID 0 data Data Fie
72. down for safety reasons This state is entered from the safe state upon receipt of a dump data telecommand While in this state Alice is dumping science data to telemetry Upon completion of the data dump Alice will return to the safe state Checkout State The checkout state is entered by command and is used to perform checkout and general diagnostics of the A ice instrument All commands are accepted from this state This state is not normally used during routine science observations Acquire State In the acquire state the Alice instrument is acquiring science data in one of the three acquisition modes histogram pixel count rate This state is entered during the acquisition phase of the MultipleAcquireDump command and it remains in this state until the acquisition is complete or the acquisition is stopped prematurely by command or due to a safety monitoring event Upon normal completion of an acquisition Alice will transition to the hold state from the acquire state 26 Rosetta ALICE User Manual Hold State While in the hold state Alice is holding a set of science data awaiting further steps or commands to either resume acquisition or dump the data to telemetry While in the hold state the instrument configuration is not changed The door and HVPS remain in their previous condition Dump State The dump state is used to dump science data This state is entered by in the dump phase of the MultipleAcquireDump command It rema
73. during EMI EMC tests 5 2 On Board Control Procedures See Section 6 9 5 3 Flight Control Procedures Commissioning Phase see Attachment 7 Technical Note 8225 COM SEQ 01 Commissioning Sequences for Alice and FOP RO ESC PL 5000 Section 5 1 All other mission phases See document Alice Standard Sequences Templates Attachment 2 8225 STD SEQ 01 and FOP RO ESC PL 5000 Section 5 1 5 4 Contingency Recovery Procedures EID B 6 5 4 The following contingencies have been identified along with possible recovery procedures Detector door does not indicate open If the detector door does not indicate open after initial commanding during Alice Commissioning Phase I several re attempts will be made over time If door still does not indicate open or detector door open indicator is faulty then commissioning will proceed except for the application of HV which may be delayed to insure that the GN gas inside the detector vacuum housing has fully leaked out to prevent HV arcing When the commissioning has resumed Alice science will take place in a degraded condition lower UV throughput and smaller spectral passband of 1200 2050 In the latter phases of Alice commissioning Alice Commissioning Phase IIT science acquisitions will begin which will make it possible for the Alice team to determine whether or not the door is actually open or closed to ascertain whether or not the detector door switch is faulty
74. e indicate progress of the Multiple Acquire Dump cycle severity normal warning Header Information ServiceType Td Service Subtype 1207 Data Field Information Remarks 60 fused Progressld enum 2 progress identifier 0 not used 1 start cycle acquisition 2 safety active 3 start missed Cycle current cycle within the MAD command 0 to TotalCycles 1 TotalCycles unsigned 8 total number of cycles requested in the MAD command SafetyStatus 7 safety status copy of current safety conditions 7 separate safety flags for 1 spare definition see HkSafety definition in Housekeeping TM package unsigned 16 bits Notes This packet is only generated each time within the execution of a MultpleAcquireDump command when the cycle reaches the point were it is ready to start a data acquisition It indicates the progress of the command and reports if the actual acquisition has been started 1 subtype 1 is used for the normal start of a cycle events subtype 2 is used as a warning for safety active and start missed events Telemetry Packet Definition Alice Packet Name Packet Function dump instrument memory Generation Rules when solicited by dump memory TC 6 5 Header Information Process ID Packet Catego Service Type 6 f Service Subtype Structure ID 8 1024 max Data Field Field Structure Memoryld enum 8 see identifies memory type of dump notes Blocks number of memory blocks in packet always 1 for Alice MemStart un
75. e Acknowledge Failure ee 08 Execution Acknowledge Success Execution Acknowledge Failure Service 3 Housekeeping Reporting Enable HK Report HK Report per SID Disable HK Report Service 5 Reporting Normal Progress Report Error Report no action Error Report ground action Error Report on board action en 6 Memory Management Load Memory Dump Memory 6 Memory Dump Check Memory 10 Memory Check 0 Service 9 Time Management Accept Time Update Service 17 Test Connection Connection Test Request 2 Connection Test Report Service 18 Context Transfer Report Context 2 Context Report Accept Context Service 19 Distribution Rosina COPS Pressure Distribution Rosina COPS Pressure Alert Giada Dust Monitor Service 20 Science Data Transfer Enable Science Report RTU S Science Report RTU Disable Science Report RTU d e y Enter Checkout Stato Command P SSS Deleted was Acquire Histogram Mode O Deleted was Acquire Pixel Mode Att TE _ CR SG H c 65 Rosetta ALICE User Manual Sub Service Requests TC Sub Service Reports TM Type Type jar SetParameter 12 sSeteeyMak _ a 14 OpenAprueDor O SS 15 Close Aperture Door Ga 16 SeghVotapO
76. e brightness of the High n aa observed object and the selected hack rate inL tial D rd Post acquisition windowing will only select events that occurred within the WinHighSpatial selected window but data volume reduction is unknown as distribution of Acquistion Counts Hackrate captured event is a priori unknown Count Rate 230 Rosetta ALICE User Manual MAD parameter Description Effect on data volume Acquisition Slots Number of acquisition slots is directly specified and determines the data volume acquisition duration is the product of the number of specified slots 1 32767 and the acquisition interval 3 ms 11 9 s No further data selection is performed Acquisition Interval 2 4 4 Non Operating Heaters Alice EID B 8 2 3 3 2 No non operating heaters are required during the hibernation phase of the mission 2 4 5 S C Powered Thermistors Alice EID B 2 3 3 4 The S C will monitor the A ice instrument baseplate TRP The TRP contains 1 primary thermistor and 1 redundant thermistor The location of the is specified in the Alice Thermal ICD see Attachment 1 2 4 6 Pyro Lines Alice EID B S 2 5 Each of the dimple actuators for the detector door the aperture door uncage and the fail safe door requires 4 A of power during a 10 ms duration See 5 2 5 4 in the Alice EID B for detailed information on the dimple actuator 2 4 7 OBDH Channels Alice EID B 2 7
77. e exceeds a preset limit then a bright object safety condition will be in effect and Alice will be safed A safety event telemetry packet will be generated If this happens then the Alice team will request time to perform engineering diagnostics First consideration will be whether the high count rate can be explained by the spacecraft pointing configuration 1 e pointed at the sun or a bright UV star If the high count rate can be explained then normal operation will resume If the high count rate cannot be explained then diagnostics will be performed on the high voltage power supply in an attempt to determine the source of the problem and to determine if this is a temporary from HV arcing for example or a permanent detector hot spot condition If it is determined that the condition is permanent but Alice is still usable then the count rate safety threshold will be raised by setting a parameter and normal operation will resume Required software modification If a problem develops with Alice that requires a software modification then the Alice team will produce a software patch After the patch is installed in Alice normal operation will resume but using the patched startup OBCP for starting Alice See the Data Operations Handbook DRD 65 2 S C Detected Out of Limits If the S C detects an out of limits during an Alice acquisition sequence see Table 5 2and EID B 82 8 for a list of Alice housekeeping parameters monitored b
78. e first assume that maximum amount of data is being dumped For all three acquisition modes the acquisition buffer can hold up to 32 kword 16 bits of data and after packaging this results in up to 19 or 17 telemetry packets depending on the 29 Rosetta ALICE User Manual ancillary data which is acquisition mode dependant If less than the full data are dumped then the duration will be correspondingly shorter When the data are dumped 1 2 or 3 science packets are dumped per spacecraft polling period All of the dump rates assume an 8 second polling interval If Alice is not polled at the assumed rate then no data is lost but the dump will take longer with a lower effective data rate As described one of the parameters for a data dump is the dump delay which allows for the reduction of the generated data rate This results in the following data rates see Table 2 9 for the full 19 packet histogram data dump in total 72452 bytes of data Table 2 9 Example dump durations and data rates Selected Dump Delay Dump Duration Average Data Rate Dump Normal 70 seconds 8 28 kbit sec Dump Slow 140 seconds 4 14 kbit sec Dump Extra Slow 280 seconds 2 07 kbit sec The maximum science data size for Alice has been set to 3994 bytes giving a maximum Alice science packet size of 4010 bytes This will allow 3 science packets to be placed in the output buffer FIFO and leave room for a few protocol packets The resulting
79. e is received Alice safety will be triggered HVPS anomaly if any of the detector voltage or current readings go out of limits then Alice Safety is triggered 19 Rosetta ALICE User Manual Temperature sensor limit if any of the Alice temperature sensors goes above an upper limit then Alice Safety is triggered The occurrence of any of these six conditions described above causes Alice to autonomously perform a safety shutdown During the safety shutdown Alice high voltage is turned down and the aperture door closed configurable Operations can only be resumed after all of the conditions have been absent for a configurable period of time Each individual condition can be masked upon command from the ground A condition that is masked is not considered when deciding to perform a safety shutdown Finally the safety shutdown can be completely overridden allowing Alice to operate even in the presence of a safety condition When a safety condition occurs Alice generates an event packet and is commanded to the safe state No data is lost when the safety shutdown occurs dump operations may still continue or the data can still be retrieved using a separate dump command Only when the safety condition disappears and the safety timeout period expires can new acquisitions which possibly open the aperture door and activate the high voltage be started This may even be a successive acquisition operation within a single still active MultipleAc
80. e per 255 seconds Non science periodic diagnostic data 60 octets per 30 Generated at the same rate and time as the Telemetry seconds housekeeping packets packets actually have a science packet ID Context instrument context 42 octets Loaded from SSMM every time when instrument starts saved to SSMM after modifications separate telecommand Event instrument operating and limited largest event Instrument generated event packages generated both error events package is 6 bytes during nominal processing and for non nominal error reporting Memory Dumps instrument memory up to 128 kbyte Incidental memory dumps for problem investigation dumps form one of the four instrument memory types during non nominal operations door performance data 128 bytes Incidental results of door performance measurements results are accessed using the memory dump service to retrieve table of results Science acquired science data depending on Depending on acquistion modes and specified data Telemetry acquisition mode dumps see MAD telecommand ZAL19226 and data and dump selection production selection rates section 2 4 3 aa eee ee ee eee S W patches software patches to be 32 kbytes Alice now has non volatile memory and does not loaded into the instrument transient only require permanent spacecraft storage of patches non volatile memory 92 Rosetta ALICE User Manual 6 8 Information Distribution Requirements During
81. ed The rate of the periodic packets can be selected by telecommand and may be between 1 and 255 seconds The size of both the housekeeping package and diagnostic package are fixed so once a packet rate has been selected the resulting data rate can be calculated Both housekeeping and diagnostic packets are fairly small with respectively 46 and 60 data bytes Table 2 8 shows some examples and the resulting data rates Table 2 8 Periodic data generation rates Data Mode Packet Rate Data Rate Data Rate HK packets only HK Diagnostic packets Nominal startup 30 sec 12 3 bits sec 28 3 bits sec High rate 5 sec 73 6 bits sec 169 6 bits sec Low rate 240 sec 1 5 bits sec 3 5 bits sec On demand data All other data generated by the Alice instrument is generated on demand only meaning that only after a specific solicitation telecommand data packets will be generated This category consists of the science data that is generated at the end of an acquisition exposure but also some special data streams fall in this category like memory dumps and event packages Event packages are very small and are therefore only small contributions to the overall data rate Memory dump packages are only used during non nominal operations and even then the amount of memory that can be dumped from the Alice instrument is very limited so this also doesn t need to be considered for the nominal data rate calculations This leaves the science data that
82. ed to 1000 write cycles when used in block write mode as in Alice To ensure that the maximum number of cycles is not exceeded a manual administration of the number of used write cycles per page will be maintained In addition to the limited lifetime the EEPROM memory will also gradually loose charge and thus eventually will loose memory contents To prevent loss of the stored information the memory should be updated or refreshed at least once every 5 years as stated in Flight Rule EMP 3 3 1 10 Software Code Patch Operation The Alice instrument provides four pages of EEPROM memory that can be used to store updated versions of the instrument flight software The instrument always starts up from code in PROM unless a problem is discovered in this code by the startup code see Section 3 1 9 After this point the instrument 42 Rosetta ALICE User Manual can be commanded to start executing code in one of the four EEPROM pages When the instrument is launched aboard the Rosetta spacecraft these four pages contain simple copies of the Alice flight software stored in PROM this version of the Alice flight software is documented in the 4 ice Flight Software Version 2 04 8225 REL 01 Revision 4 Change 0 dated 10 18 2004 When executing code in PROM the contents of the EEPROM memory can be modified using the LoadMemory telecommand In each separate command up to 128 bytes of data can be loaded When the need for changes in the o
83. ee the Rosetta Alice Calibration Cookbook document A ice data files uncalibrated and calibrated science calibration data HK event memory dump observing log etc will be available to the A ice team via a password protected webpage at http www boulder swri edu ralice 33 Rosetta ALICE User Manual The data will be archived locally i e general office backup tapes and project specific CDs DVDs to be distributed to team members typically one or two times a year as well as by the Rosetta Mission In the latter all the mission data will be archived according the Rosetta Archive Generation Validation and Transfer Plan The Rosetta Science Data Archive will be part of the Planetary Science Archive PSA The PSA is an online database implemented by ESA RSSD and used for all of ESA s planetary missions It is accessible via http psa rssd esa int The underlying standard of the PSA is the Planetary Data System PDS standard from NASA More information is available on the web site http pds jpl nasa gov Following the Rosetta Archive Plan the Alice team will submit engineering and calibrated data files on a regular basis after each phase as defined in the mission plan to the archive To provide the correct format for the archive auxiliary IDL programs will be run on the Alice data to create the appropriate PDS labels directory structure and additional informational files Note that these programs do not change the
84. effective downlink rate depends on the spacecraft polling rate The simple Alice processor may take up to about 3 seconds to format a science packet depending on the specific science mode If the spacecraft could only support a nominal polling rate of 8 seconds Alice could fill the output FIFO to fit the maximum 6144 words block size So at low polling rates this will give the best available downlink rate One single private telecommand MultipleAcquireDump MAD is used for the nominal Alice science operations Parameters in this command specify the acquire dump cycle that forms the basis of all Alice science operations The command allows for the specification of three different science acquisition modes acquire histogram mode acquire pixel list mode with two termination options acquire count rate mode Each of these acquire operations store the acquired science data in the internal Alice memory Once the acquisition is complete then a dump operation specified in the same MAD telecommand is used to transmit the acquired science data via the telemetry interface The MAD command is very flexible allowing many possible combinations It is possible to resume an acquire following a dump adding to the previous data without erasing it It is also possible to perform multiple dumps on the same data for the purpose of looking at more than one window or perhaps by collapsing the data in different ways The acquire function has the following p
85. er NPWDA580 AL HIB HTR PLCL 13A CUR LPW03069 ANA gt Call engineer NPWDA890 ALICE PS2 118 CUR ANA LPW03206 Call engineer Parameter on OMS monitoring list service 12 Monitoring status controlled by ALICE switch ON procedure Recovery action start weg ep ee germ NTSA0062 001 ALICE TRPP ANA degC 17500001 Call engineer NTSA0188 002 ALICE TRPR ANA Call engineer 4 Mode Descriptions 4 1 Mode Transition Table See Section 2 3 7 for detailed description of the instrument states Section 2 4 3 with respect to data generation rates and Section 2 4 2 for the relation to power consumption start of acquire Figure 4 1 1 The Alice top level mode transitions Instrument Off power on Standby safe hold checkout Dumping dump safedump When Alice is performing science data acquisitions in response to a Multiple Acquire Dump MAD telecommand the operating state reported in the Alice HK packet may change Depending on the parameters specified with the MAD command the instrument will cycle through different states before completing the command Acquire state Dump state Standby state acquire phase of the specified duration generated and sent to the spacecraft when an acquisition time has been specified the instrument will start with
86. er List context with Default Values Parameter Default value Description HTRSENSEGRATING 0 0 primary temperature sensor 1 secondary 1 HTRSENSEMIRROR 0 0 primary temperature sensor 1 secondary 2 DOORENABLE 1 1 1 on safety 0 dont close 90 Rosetta ALICE User Manual Parameter Default value Description 3 DACADCFACTOR 231 multiplication factor to convert from HV DAC to factor 240 4 EVENTSAFETY 0 0 ground safety event 1 on board event 5 DISCRIMINATOR 30 discriminator level set point commanded at start of acquisition 6 HOTSEGI 0 7 HOTSEG2 0 8 HOTSEG3 0 9 HOTSEG4 0 all hot segment registers are initialized to zero bottom 10 5 0 left corner of detector array 11 HOTSEG6 0 12 HOTSEG7 0 13 HOTSEG8 0 14 HVLEVEL 5 250 V high voltage set point DAC counts commanded at start of acquisition 15 HVSTEPSIZE 4 gt 94 V DAC counts for HV steps during HV rampup 16 HVRUNTIME 2 192ms HVPS task run interval both for steps and checks specified in kernel clock ticks 17 HVMAXSTRIPI 168 1uA maximum accepted strip current in ADC counts 18 HVMINANODEV 188 550 V minimum accepted anode voltage when HV setting is reached in ADC counts 19 HVMAXANODEV 245 650 V maximum anode voltage in ADC counts 20 HVMCPTOL 8 200 V allowed McpV gt HvSet error ADC gt DAC 21 HVFAILANODE
87. ermanently stuck closed Aperture door open sensor always indicates open If the aperture door open sensor continues to indicate open after commanding closed then a door warning event will be generated If this happens then the Alice team will request time to perform engineering diagnostics During this period Flight Rules should be followed assuming the door is open The indication from the door close sensor will be considered If it behaves as expected then the door open sensor will be suspected faulty One or more science observations will be made to determine if the door is really closed in which case the sensor will be declared faulty If this happens then operation will proceed normally with the understanding that the door open sensor is faulty If it appears that the sensor is correctly indicating that the door remains open then the Alice team will carefully consider whether it is worth further attempting to move the door for fear of having the door become stuck in the closed position Alice can be configured by parameter to not attempt to close the door and operations can proceed normally in this configuration except that the door will not be closed when Alice is safed or shut down Aperture door sensors indicate conflicting positions If the aperture door sensors indicate that the door is both open and closed or a continuous indication of being neither open nor closed then a door warning event will be generated If this happens then t
88. execute a specific test or perform a one time operation the code need not be loaded in EEPROM at all The current system uses less than 50 of the available RAM space and code can also be executed from this RAM memory 3 1 11 In Flight Aperture Door Performance Tests The aperture door in the Alice instrument is a limited life item and proper operations are critical for successful instrument operations The design lifetime for the aperture door is 10 000 door cycles During instrument testing an extensive verification tested the door for 20 000 operations but in the original version 2 03 of the flight software which still resides in PROM there was no means to determine the operations of the door in the flight instrument The Alice Flight Software version 2 04 was extended with a door performance measurement a minor buffer overrun bug was corrected in version 2 05 This measurement function performs a precise measurement of the door operation using the two optical switches on the door to determine the door open and door close position event times during a door operation The measurement function is a special function which in order to reach the 33 ms resolution has to temporarily suspend normal software operations For each door movement two time measurements are performed the first one determines how much time it takes for the door to start moving clears the door closed switch and the second measurement determines how much time it takes to rea
89. fails normal warning Qo CHI QVI e Da SX es 2 3 5 Timing Requirements The most important consideration regarding timing is the correct time tagging of each UV spectral image Using the time tag we can derive the instrument look angle for each image Whenever Alice is powered on from a powered off state an update of Alice s internal time of day clock shall take place in accordance with Section 2 8 1 8 of EID A During times when Alice is powered 22 Rosetta ALICE User Manual on and operating the instrument s internal time of day clock shall be updated when commanded by the OBDH time synchronization command The required absolute accuracy of the spacecraft time of day updates is to plus or minus a few seconds However the scheme used by Alice shall provide for much better accuracy The Alice internal clock will keep relative time between updates at a maximum accuracy of 1 256 s to accommodate time binning of rapid detector readouts during observations of fast temporal events However note that since the internal clock is not synchronized when Alice is first powered on the first packet generated the Alice power on event packet will contain unsynchronized time in the time field We expect that Alice will receive a time update shortly after this happens It is not possible for Alice to receive a time update packet prior to generation of the power on event packet During normal operation Alice requires a time update command every 30
90. formed by hardware once configured by software The software only intervenes at the beginning and end of the acquisition or if a problem is detected The data dumped from the pixel list mode once completed consists of the list of pixel events and integrated time marks The data dump can also be filtered so that only those events that occurred within a certain region of the detector are included in the data dump Count rate mode In count rate mode only the total event count within a given user defined time interval is stored on a regular basis The actual event addresses are ignored The event count is stored sequentially in the memory array as in pixel list mode except that the value stored in the list is only the total count for each time interval with no event location information and no time hacks This mode provides a record over time of the variation in count rate observed by the detector Unlike the other two modes where the acquisition is performed by hardware in this mode the acquisition is implemented in software The software is programmed to read the total count from the detector on a periodic basis and store that count 425 Rosetta ALICE User Manual in sequence in the acquisition memory The data dumped from the count rate mode consists of the list of event counts Note that there is also an analog count rate reported in the HK data Section 3 1 8 Operating states of the Alice instrument AFS implements a set of states
91. g a given integration time events are accumulated one at a time into their respective histogram array locations creating a two dimensional image The read increment write operation saturates at the maximum count of 65 535 so no wrap around can occur in the acquired data The time information of the individual events within the acquisition is lost in this process but using appropriate acquisition durations high signal to noise ratio data may be acquired even from dim objects At the conclusion of the integration period the acquired data can be down linked in telemetry In order to limit the required telemetry bandwidth the histogram memory can be manipulated to extract only data from up to eight separate two dimensional windows in the array for downlink and within these windows rows and columns may be co added to further reduce the number of samples Pixel List Mode In this mode the acquisition memory is used as a one dimensional linear array of 32 768 entries The pixel list mode allows for the sequential collection of each x y event address into the linear pixel list memory array Periodically at programmable rates not exceeding 256 Hz a time marker is inserted into the array to allow for time binning of events This mode can be used to either a lower the downlink bandwidth for data collection integrations with very low counting rates or b for fast 39 Rosetta ALICE User Manual time resolved acquisitions using relatively brig
92. he Alice team will request time to perform engineering diagnostics During this period Flight Rules should be followed assuming the door is open A troubleshooting approach will be devised based on the indications from the sensors One or more science observations will be made to determine the actual position of the door This situation will most likely indicate that one or both of the sensors is faulty rather than sticking of the door In this case the likely response will be to proceed normally using alternate information source such as detector count rates to determine that the door is in the expected position Heater temperature sensor disagreement Alice has two temperature sensors for each of two heaters If the two sensors disagree by more than 5 degrees C then one of the sensors will be suspected faulty Then by comparing the temperature sensor levels to the other temperature sensors in the instrument or by observing the sensor responses to activation of the heater an attempt will be made to determine which sensor is providing correct values The instrument will then be commanded by setting a parameter value to use the good sensor for heater temperature regulation Heater temperature sensor loss If both temperature sensors for a given heater are suspected faulty then operation of the Alice heaters will switch to an open loop timeline commanded method The Alice team will compute the appropriate on and off times for the heater s
93. ht targets in the Alice FOV At the conclusion of this acquisition period the total amount of generated data can be further reduced by selecting only events that have occurred within up to eight separate windows for downlink Count Rate Mode In this mode the acquisition memory is again used as a one dimensional linear array of 32 768 entries The count rate mode is designed to periodically configurable between 3 ms and 12 s collect the total detector array count rate sequentially in the linear memory array as if the entire instrument were an FUV photometer This mode allows for high count rates from the detector up to 10 kHz without rapid fill up of the array It does not however retain any spatial or spectral information for broadband photometric studies Depending on the required periodic acquisition rate total acquisition durations of up to 98 seconds to 100 hours are possible 3 1 7 Detector Acquisition Durations The actual start and end time of any acquisition is reported in the header of the science data dump both specified in instrument spacecraft MET The Alice post processing chain i e Lima Mike and November includes this information in the produced FITS files and calculates the acquisition duration from these numbers as the difference between the start and stop times For histogram and pixel list acquisitions this calculated number represents the best available knowledge on the actual duration of the acquisition The acquis
94. i 77 DetectorCounts unsigned 24 total counts from detector event counter 114 bytes to here Telemetry Packet Definition Alice Packet Name Science pixel Packet Function provide pixel mode science data Generation Rules receipt of Multiple Acquire Dump telecommand 192 26 when specified dump is executed and pixel mode data available one dump can consist of up to 17 TM packets Process ID Service Type Structure ID 0 Packet Length 3994 max data configuration data context see notes high ROSINA pressure reported during acquisition minimum value if no ROSINA pressure reported during acquisition no ROSINA pressure reported during acquisition unsigned 16 commanded integration time AcqCount unsigned 16 commanded total count 87 Rosetta ALICE User Manual AcqControl enum 1 acquisition control count or time 0 time based 1 count based starting memory address of events in packet PixelData unsigned 16 list of events X 1931 max 3994 132 3862 octets gt 1931 words Notes Housekeeping data item is the same as data field of housekeeping data telemetry packet not including SID Parameter data item is the same as data field of context telemetry packet 18 2 Total packet length is variable depending on quantity of science data estimated overhead 132 octets remainder is pixel list up to 3862 octets 1931 pixels All of the packet fields from the beginning to the DetectorCounts fie
95. ical telecommands to the ground Rather we would simply include the confirmation telecommand following the critical command in the timeline 2 3 2 Autonomy Concept Almost all of Alice operation is not autonomous but rather in direct response to a command Alice software does however implement a safety monitoring algorithm The following safety conditions are monitored continuously whenever Alice is operating Dust flux level e Bright object e ROSINA pressure trend e ROSINA pressure alert e HVPS anomaly Temperature sensor limit Dust flux level Alice receives GIADA dust messages via the information distribution service If the level rises above a configurable limit then Alice safety is triggered Bright object if the detector count rate goes above a configurable limit then Alice safety is triggered ROSINA pressure alert Alice receives ROSINA pressure information via the information service at intervals controlled by ROSINA or the spacecraft If the instantaneous ROSINA pressure level is above a configurable threshold then a pressure alert condition exists and Alice safety is triggered ROSINA pressure trend If the instantaneous ROSINA pressure level is below the configured threshold an expected safe time is calculated based on the ROSINA pressure and the ROSINA pressure trend Based on this safe period and a configurable maximum prediction limit a timer is set When the timer expires before a new ROSINA pressure messag
96. ice data acquisition and dump cycle Verification Rules acceptance correct telecommand length current state is safe hold or checkout and correct dump specification for all used slots execution always after confirmation but failure will be reported when the command execution is terminated due to a dump error or an Stop Acquire TC 192 7 Header Information Data Field Information Remarks AcquisitionMode enum 2 Meaning of fields AcqDuration MarkInterval DumpSpecifications are 0 histogram mode dependent on the selected AcquisitionMode 1 7 pixel list time lim 2 7 pixel list count lim 3 count rate po unused aperture door open stimulator on memory clear if true then a test pattern is generated instead of a real acquisition acquisition time seconds for modes 0 and 1 total event counts for modes 2 and 3 MarklInterval unsigned 8 bits unused for mode 0 time mark interval for modes 1 and 2 format per TC insert mask register see h w spec acquisition interval for mode 3 in units of 3 ms Repeat unsigned 8 number of cycle repetitions new in version 2 05 a value of 255 defines an endless cycle repeat so the acquisition continues till explicitly commanded to stop overall time in seconds between successive cycle starts spectral window lower inclusive 0 1023 spectral window upper inclusive 0 1023 spectral collapse factor 1 1024 spatial window lower 0 31 spatial wi
97. ins in this state until the data dump is completed or cancelled Upon normal completion it returns to the hold state Note that this design means that Alice can essentially only perform one high level function at a time It is either acquiring data or dumping data but not both Lower level functions such as command and telemetry processing and safety monitoring are still performed in all states Refer to Figure 2 3 2 for a state diagram showing the transitions between the Alice operating states 22 TC_EnterSafe SafetyCondition TC_StopAcquire EndOfDump StartDump TC StopAcquire EndOfAcquire TC EnterSafe not shown SafetyCondition Hold to Checkout via TC EnterCheckout Note states are shown in black boxes state transitions in red boxes Figure 2 3 2 The Alice software operating state diagram 295 Rosetta ALICE User Manual 2 4 Budgets DRD 12 2 2 4 4 Mass Alice has a measured mass of 3 06 kg 2 4 2 Operating Power Alice EID B S 2 4 3 Power consumption for the A ice instrument is listed below in Table 2 6 The numbers for end of life EOL are best estimate values Table 2 7 gives the beginning of life BOL power breakdown per instrument subsystem Table 2 6 Alice Power Consumption Average Power Predicted Average Power Experiment BOL W EOL W Interface Mode 128 V Power Interface mode 1 Safe Mode with HVPS output disabled
98. ion Process ID 92 12 Service Type 192 21 Structure ID N A 0 data Data Field Information Data Field 75 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Set discriminator level Alice Packet Function sets the detector discriminator level Verification Rules acceptance always execution always Header Information Process ID 92 12 Service Type 192 22 Structure ID 2 data Data Field Information Data Field Remarks 4 unused DiscLevelSet discriminator level DAC counts Telecommand Packet Definition Alice Packet Name Self test Packet Function runs the instrument self test Verification Rules acceptance must be in checkout state execution always after confirmation see notes Header Information Process ID 92 12 Service Type 192 23 Structure ID N A 0 data Data Field Information Data Field 7 Notes critical Execution of this command initially sets the result byte Hk Test Status see TM 3 25 to Oxff no tests completed succesfully The test specification byte Pm Test Mask specifies which tests are to be executed see specification in power on event package 5 1 1 indicates selected Next the selected tests are sequentially executed starting with the test specified by the least significant bit When a test is completed successfully the corresponding bit in the result byte is cleared This continues until all selected tests have been completed Completion of all
99. ions In general Alice only uses unstructured memory dumps to verify the contents of PROM and EEPROM memory area s although the command set allows for memory dumps of all used memory types A special predefined case is the dump of the results of the Door Performance Measurement The Door Performance Measurement is a special embedded function that can be activated by a commanded jump to a specific address in the code memory space This function was added in version 2 04 of the flight software The measurement results are stored in a cyclic buffer located at address 0x b600 After performing a number of door performance measurements the results can be retrieved by dumping this 128 byte memory buffer The buffer contains up to 64 entries of 4 words 16 bits each Each entry in the buffer describes the timing results of one commanded door movement cycle flap For each move open close two parameters are measured indicating when the movement started and when the movement completed The results of the measurement are reported in units of 33 microseconds e Open start movement e Open completed movement e Close start movement e Close completed movement 6 7 SSMM Utilization SSMM Utilisation Mission Phase any Instrument Alice MByte Non science periodic housekeeping 46 octets per 30 46 bytes HK data every 30 seconds nominal when Telemetry seconds instrument operating can be adjusted by telecommand for a rate between once per second to onc
100. is generated when the pressure exceeds a predefined limit defined by Rosina Receipt of this packet indicates that Rosina is safed and no more pressure distribution messages will be received This packet is processed identical by Alice to the ROSINA pressure message 19 10 69 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Giada dust monitor Alice Packet Function provide dust alert to Alice execution always Process ID 12 Service Type 12 Structure ID 2 data Remarks dust flux in particles m 2 minute Notes This packet provides dust information to instruments EID A says that flux saturates at a count of about 600 and that the value will read as OxFFFF Alice needs this information for its internal safety procedures Telecommand Packet Definition Alice Packet Name Enable Disable Science Alice Packet Function enable disable instrument science data output Verification Rules acceptance correct packet length correct PID execution always Header Information Process ID 92 12 Service Type 1 2 see notes Structure ID N A 2 data Data Field Information Data Field Remarks process ID of science generation source value always 92 Notes Sub type 1 enables science output sub type 2 disables the science output This command does not have any effect on Alice operation Telecommand Packet Definition Alice Packet Name Enter safe state Packet Function cause Alice to enter the safe operating
101. is necessary to define what is meant by modes and states For the Rosetta project the term mode as applied to the instruments are general modes and is used for modeling data rates power consumption and for error checking that commands can be performed such modeling is done e g in the EPS these modes are off safe checkout Acquire Stand by and Dump see Figure 4 1 1 in Section 4 However within the Alice project the term mode is used to describe data acquisition modes of the instrument such as histogram pixel list and count rate Finally also within the Alice project the term state is used to refer to the operating state of the instrument listed below which is part of the instrument configuration and is more directly related to the Rosetta project s term mode Instrument Acquisition Modes Alice acquisition modes are not directly related to data rates This section describes the acquisition modes as they relate to software Alice science operations and objectives are discussed in more detail in Sections 1 3 3 2 and 6 The three acquisition modes are image histogram pixel list and count rate The modes are all similar in the sense that during an acquisition the detector is acquiring photon events and these events are accumulated by Alice in the acquisition memory over a period of time the integration time or acquisition time In every mode the detector electronics always produces a 2 D address indicati
102. ition duration is not always exactly the same as the commanded acquisition time This is easy to understand for special cases where an acquisition was terminated early either by user command or because a safety condition occurred but also for the nominal acquisitions there will be a difference between commanded and actual acquisition time The reason for this is that the instrument software controls the acquisition hardware in such a way that also adds a kind of granularity to the acquisition duration which is dependant on the specific acquisition mode For the four different cases the consequences of this quantization will be discussed These timing measurements apply to each of the separate acquisitions within a MAD commanded multi acquisition sequence The start time of an acquisition within a MAD multi acquisition sequence with a fixed cycle duration is checked every 0 5 seconds This means that the start of an exposure within a multiple acquire cycle may occur up to 0 5 seconds later than expected from the commanded cycle duration This start time error is not cumulative though the start times of the multiple exposures are all related to the initial acquisition command start time 3 1 7 1 Histogram Acquisition During a histogram acquisition in parallel to the histogram acquisition a coarse count rate data set of up to 100 elements is acquired This count rate data is included in the header of the data dump and the Alice post processing chain p
103. ke place when the TM packet is considered a solicited TM packet according to Table 2 8 2 2 pages 56 57 AND the TC packet specifies that it solicits a direct response by specifying a PUS field value of 010 EID A 2 7 2 2 page 18 In all other cases the PAD field of generated TM packets will be set to zero Note that Alice does not copy the PAD field from any telecommand into the service 1 telemetry packets In version 2 05 dated October 2006 the full PAD field copying functionality was added It includes the copying of the PAD field from any telecommand into the service 1 telemetry packets PAD is a field in TM defined as a filler byte that ensures the 16 bit boundary alignment of the complete TM packet see EID B 2 7 2 1 94 Rosetta ALICE User Manual 7 Rosetta Alice and STB Configuration and Use To support mission operations an Alice EQM Electrical Qualification Model is maintained installed on the spacecraft EQM at ESOC in Darmstadt The Alice EQM contains an electrical equivalent of the flight instrument that only lacks the optical components of the instrument The electronic modules included in the EQM are LVPS HVPS and Detector electronics The EQM includes the door actuator heater resistors and temperature sensors The software configuration of the EQM is identical to the flight model it contains the same software in PROM and also the EEPROM contents are maintained to match the EEPROM contents of the flight
104. l during acquisition ADC counts PressMax real 8 special high ROSINA pressure reported during acquisition minimum value if no ROSINA pressure reported during acquisition real 8 special low ROSINA pressure reported during acquisition maximum value if 86 Rosetta ALICE User Manual no ROSINA pressure reported during acquisition StartTime StopTime DumpNo SciSeq X 16 CountRatelnterval CountRateltems CountRateData AcqTime WinLowSpectral WinHighSpectral CollapseSpectral WinLowSpatial WinHighSpatial CollapseSpatial unsigned 16 Pixelltems unsigned 16 count of pixels in packet StartPixel start pixel number in packet PixelData unsigned 16 bits list of N pixels XN max N 3994 364 3630 octets 1815 words Notes Housekeeping data item is the same as data field of housekeeping data telemetry packet not including SID Parameter data item is the same as data field of context telemetry packet 18 2 Total packet length is variable depending on quantity of science data estimated overhead 364 octets remainder is pixel list up to 3630 octets 1815 pixels All of the packet fields from the beginning to the DetectorCounts field inclusive are common to all science data packets CountRateData field always has 100 slots for count rate data The actual number of items in the list may vary and is indicated by the CountRateltems field Any unused slots in CountRateData will have undefined values ing th
105. l instruments and modes so more interference tests are still planned by ESA for sometime after 2006 possibly much later 3 2 6 Operational Constraints The Alice flight operational constraints a k a the Flight Rules are presented below this is version 2 2 dated 14 April 2005 01 BRIGHT OBJECT AVOIDANCE BRT BRT 1Thermal Protection i In order to prevent thermal damage Alice will never be pointed within 11 deg of the Sun with either the aperture door or the fail safe door open ii The front aperture or the fail safe door can be pointed at the Sun indefinitely even at 1 AU when the aperture door and fail safe door are closed BRT 2 Excessive Count Rates In order to prevent excessive count rate backgrounds whenever HVPS is ON Alice will never be pointed i within lt 20 deg of the Sun with the aperture door open or ii within lt 10 deg of the Sun with the fail safe door open BRT 3 Excessive Count Rates i Unless otherwise stated by the Alice team in order to prevent excessive count rate backgrounds when HV gt 2500 V and with the aperture door or fail safe door open no portion of the Alice slit shall ever be 51 Rosetta ALICE User Manual pointed within 0 5 deg of any source in the Alice Bright Star Avoidance List Attachment 11 in this document 02 INITIAL START UP INIT INIT 1Thermal Protection i The temperature reference point temperature shall be between 20 lt T lt 50 03 H
106. laces this data in the second extension of the generated FITS file The minimum time resolution for this count rate acquisition is 100 ms for acquisition durations less than 10 seconds and the maximum is 25 5 seconds for acquisitions of 2550 seconds or more For shorter acquisitions the 100 element count rate buffer is only partially filled and for acquisitions longer than 2550 seconds 42 5 minutes only the initial part of the acquisition is covered in the count rate measurements This count rate measurement interval also determines the granularity of the histogram acquisition end time check This means that for short histogram acquisitions the commanded end time is checked every 100 ms but for longer acquisitions the check is performed less frequently The worst case situation occurs for acquisitions longer than 2550 seconds for which the termination condition is only checked once every 25 5 seconds this means that worst case such an acquisition could continue up to 25 5 seconds longer than commanded Except for the very short acquisitions less than 10 seconds where the acquisition duration may last up to 100 ms longer than planned the maximum acquisition extension is always less than 0 4 of the commanded acquisition duration In all cases the reported start 40 Rosetta ALICE User Manual and end times are the best available for the start and end of the actual acquisition i e histogramming operation an example a histogram acquisiti
107. ld po Notes Telecommand deleted after addition of the Multiple Acquire Dump telecommand 192 26 Telecommand Packet Definition Alice Packet Name Clear acquisition Packet Function Verification Rules acceptance always execution always after confirmation Header Information Data Field Information Data Field Remarks FE Notes critical clear memory command causes dump type to be reset to histogram a dump following a clear will result in a blank histogram dump Telecommand Packet Definition Alice Packet Name Set parameter Packet Function sets the value of an internal parameter Verification Rules acceptance correct packet length valid parameter ID execution always Header Information Data Field Information Data Field Remarks Parmld parameter identification location in table 0 39 ParmVal Notes For 16 bit parameters this command must be used twice to update both 8 bit portions of the 16 bit parameter This operation is not atomic so care must be taken to make sure that the instrument is in a reasonable mode for this type of update Telecommand Packet Definition Alice Packet Name Set safety mask Packet Function sets the value of the safety mask Verification Rules acceptance correct safety ID 2727 Rosetta ALICE User Manual 1 1 execution always after confirmation Header Information 12 i 12 Process ID Service Type Structure ID 2 data Data Field Information Data
108. ld inclusive are common to all science data packets The PixelData field is always 1931 words long The total number of items stored may be less and is indicated by the Pixelltems field The StartAddr field indicates the starting address in acquisition memory of the first pixel in the PixelData field Note that addresses are not necessarily contiguous due to windowing Telemetry Packet Definition Alice Packet Name Packet Function provide count rate mode science data receipt of Multiple acquire Dump telecommand 192 26 when specified dump is executed and count rate mode data available one dump can consist of up to 17 TM packets Header Information Service Subtype Structure ID p20 Packet Length 3994 max data Data Field Information Data Field Field Structure SID enum 16 unsigned 8 unsigned 8 McpStartV unsigned 8 McpStopV unsigned 8 StripMaxl unsigned 8 unsigned 8 unsigned 8 N StripMinl StripStartl StripStopl unsigned 8 HkData unsigned 8 44 ParmData unsigned 8 42 PressMax real 8 special high ROSINA pressure reported during acquisition minimum value if no ROSINA pressure reported during acquisition PressMin real 8 special low ROSINA pressure reported during acquisition maximum value if no ROSINA pressure reported during acquisition unsigned 3 unsigned 5 DetectorCounts unsigned 24 total counts from detector event counter 114 bytes to here AcqCount u
109. le 2 10 Acquisition base data volumes Acquisition Maximum Size Mode Packets Acquisition Limits Selection Histogram 72452 bytes commanded acquisition duration amount window and 19 packets of produced data is always constant collapse factor Pixellist Timed 68040 bytes commanded acquisition duration limits Window number of events captured actual events captured depends on event rate of observed object 17 packets Pixellist Count 68040 bytes commanded maximum number of captured Window events therefore acquisition duration needed to acquire the amount of events may vary 17 packets CountRate 67644 bytes maximum number of entries is commanded as is the duration of each slot so acquisition duration and produced data can be calculated 17 packets 1 Due to the periodic checking of the limit values the actual acquisition may acquire slightly more events than commanded 31 Rosetta ALICE User Manual Acquisition Maximum Size Acquisition Limits Mode Packets q 2 Due to the different sizes of the annotation data in the science packets the number of science TM packets needed to store the results of an acquisition vary slightly 17 to 19 packets MAD parameter Table 2 11 Acquisition data volume modifiers Description Effect on data volume Acquisition Mode One acquisition mode as listed Determines maximum base volume in Table 2 10 Repeat Number of acquisi
110. librate with its surroundings Following this equilibration period high voltage will be applied to the detector s MCP stack using a very slow high voltage ramp up procedure At the completion of the HV ramp up the detector will be operating at the full operational MCP voltage level Image exposures of the dark sky will be taken along with detected event Pulse Height Distribution PHD data to ascertain the health and status of the detector and the optics Aliveness Functional Tests These tests consist of turning on the instrument the gradual ramping up of the high voltage to Alice s detector to the full operational high voltage level and brief integrations of the dark sky to observe Lyman a emission observe two UV calibration stars a and y Gruis and to collect pulse height distribution PHD data of valid events recorded by the detector These data will be used to ascertain the health and status of the detector and the optics The first observations of the UV bright stars will be made in count rate mode Both stars will be observed by physically scanning slewing the spacecraft orthogonal to the length of Alice s entrance slit at a rate of 0 005 deg sec for 1000 sec 47 Rosetta ALICE User Manual binning at 0 096 second providing a of 5 6 nominally centered on the target Two such scans 1 going back and forth will be performed for each star The second observations will be made pixel list mode with a si
111. lice investigations Determine the production rates and spatial distributions of the key parent molecule species H20 CO and thereby allowing the nucleus coma coupling to be directly observed and measured on many time scales in order to study the chemical heterogeneity of the nucleus and its coupling to the coma Obtain an unambiguous budget of the cosmogonically most important atoms and S through the detection of their emissions far from the nucleus This is required to understand their production processes and to derive the elemental composition of the volatile fraction of the nucleus Coupled to the measure of the major molecule abundances of the nucleus this will give us the total contribution of the secondary parent species to the compositional makeup of the nucleus Study the onset of nuclear activity and nucleus output variations related to changing solar aspect and nuclear rotation with unprecedented sensitivity Additional scientific themes Alice will address include the following Spectral mapping of the complete nucleus at far UV wavelengths to characterize the distribution of UV absorbers on the surface in particular icy patches and organics Photometric properties and ice rock ratio of small grains in the coma as an aid to understanding the size distribution of cometary grains and how they vary in time Also studying the grain coma to establish the relative contributions of the nucleus and coma grains to the o
112. limits ur Alice off Anode V limits um Alice Strip I limits um Alice off Mirror Temp limits Alice off Grating Temp limits um Alice Det Elec Temp limits um Alice off Det Housing Temp limits urn Alice off el ola Instr Elec Temp limits turn Alice off Instr Housing Temp limits turn Alice off Major version limits Alice off Minor version limits turn Alice off High Voltage Set Point 4050 Volt lt LALO0040 0 Volt turn Alice off eee Parameter read error event turn Alice off Doo 64 Rosetta ALICE User Manual 6 Data Operations Handbook DRD 65 2 This section presents a detailed description of the Alice telemetry and telecommand data formats within the framework defined by Rosetta The Rosetta TM TC concept is based on a number of standard services with related requests telecommands and reports telemetry and specifies packets within the CCSDS telemetry and telecommand standards Each packet is identified by a service and a sub type number The Alice instrument supports all the standard services The instrument specific telecommands are captured in the Private telecommands section In the table below an overview of the requests and reports is given The separate telecommand and telemetry packets are described in detail in the two sections following this table Sub Service Requests TC Sub Service Reports TM Type Type Service 1 TC i Acceptance Acknowledge Success Acceptanc
113. milar scanning motion for 200 sec time hack interval of 0 125 sec providing a FOV of 2 x 6 nominally centered on the target Optical Alignment Check The purpose of this observation will be to determine the position of Alice s FOV with respect to the center of the wide angle camera s FOV Alignment checks will be made during the Commissioning Phase Alice Commissioning Phase III see Attachment 7 and active checkouts and will consist of count rate and pixel list scans as described in Sections 2 3 7 and 3 1 6 and jailbar observations A jailbar is a series of histogram images with pointing shifts typically by a fixed amount between each exposure For the case of these alignment observations the shifts are typically small 0 01 deg compared to the width of the narrow part of the Alice slit 0 05 deg to provide overlapping images centered on a calibration Each of these Alice histograms exposures will result in a 2D spectral image 1024 x 32 pixel format The spectral images taken in this sequence of observations will allow a determination of the boresight direction of Alice s FOV with respect to the known position of the star and relative to the NAVCAM camera which will take images several jailbar points The jailbar exposures will also provide a measurement of the slit throughput as a function of distance from the slit center For more detailed information about these commissioning phases and sequences please see Technical
114. minutes in order to keep the internal clock synchronized within acceptable limits lt 15 ms Since power on event packet always has an unsynchronized time field it may complicate DMS handling of these packets Under normal conditions when Alice boots as expected the contents of these packets are not important and they can be discarded or routed in any way convenient to DMS However if Alice ever fails to boot normally then the Alice team will request that the contents of the power on event packet be made available if it is produced for the purpose of providing diagnostic information about the Alice boot up process Version 2 03 PROM flight software During science data acquisitions execution of MultipleAcquireDump telecommand Alice was ignoring any time synchronization requests in order not to influence the timing of the acquisition function The received synchronization requests though will be acknowledged by Alice if requested During commissioning it was discovered that the instrument internal clock started to lag behind during long acquisition sequences where multiple time synchronization operations were ignored Measurements showed a unsynchronized internal clock drift of about 43 2 sec day Analysis showed that this was caused by a hardware error in the Alice clock circuitry instead of dividing the oscillator frequency by 4000 it was divided by 3998 hence the interrupt rate was 4000 3998 1 0005 sec or 0 5 ms after the desired 1
115. mmand Packet Definition Alice Packet Name Time Update Alice Packet Function provide time synchronization update to instrument Verification Rules acceptance correct packet length execution always Header Information Packet Category Service Type 9 Service Subtype 67 Rosetta ALICE User Manual N A Data Field Information Data Field Remarks SCET spacecraft elapsed time see notes for format Notes Time is formatted as 32 bits of whole seconds and 16 bits of fractional seconds The upper bit of the seconds field is not used here so there is effectively 31 bits of seconds Execution is a no operation when a Multiple Acquire Dump command is in progress Telecommand Packet Definition Alice Packet Name Connection Test Alice Packet Function request connection test report Verification Rules acceptance always execution always Header Information Packet Category Service Subtype Structure ID Packet Length Data Field Information Data Field Field Structure This packet has no application data fields Telecommand Packet Definition Alice Packet Name Report Context Packet Function request instrument produce context report 18 2 Verification Rules acceptance always execution always Header Information Process ID 92 Packet Catego Service Type Structure ID N A data Data Field Information Data Field Field Structure Remarks This packet has no application data fields Notes This telecommand executes in the slow th
116. mode 2 Operating detector and HVPS on and ds collection proceeding mode 3 Decontamination Operation Operating Heaters on 2 s aperture door opening time Table 2 7 Alice Power Breakdown per Subsystem Power Levels Watts Component 7 1 2 Mode3 LVPS OAP Heater 00 001 1 Grating Heater 0 0 oof 11 TotalPower 6 40 60 Mode 1 Safe Mode Mode 2 Operating Data Collection Mode 3 Optics Decontamination operating with heaters on 2 4 3 Data Rates Housekeeping and Science The instrument generates two separate data streams a periodic stream of housekeeping an demand stream that occurs in a single burst at the completion of an acquisition Both data streams are inserted into an output FIFO 16 kbyte that is periodically nominally every 8 seconds read by the spacecraft 28 Rosetta ALICE User Manual Periodic data The instrument will after power up start generating housekeeping packets at the rate defined in the parameter table parameter 34 HKRATE see table in Section 6 5 nominally one packet per 30 seconds As long as Alice remains powered on the generation of housekeeping packets continues but the rate may be changed by telecommand In addition the instrument can be commanded to add a diagnostic package to the stream of periodically generated packages This package will be generated at the same time and rate at which housekeeping packages are generat
117. modes using both fixed and scanning pointing 3 2 4 5 Asteroid Flybys Detailed operations are still to be determined but as with other phases will include exposures in histogram and pixel list modes using both fixed and scanning pointing The primary objective will be surface reflectance studies 3 2 4 6 Comet Rendezvous Mapping and Escort During these comet phases standard science observations with A ice will occur During these observations exposures that vary from a few seconds to much longer for deep spectral imaging will be taken depending on the minimum desired radiance level to be detected Both imaging and non imaging observations are planned During the imaging runs Alice will be slowly scanned in the direction orthogonal to the length of the entrance slit to allow the build up of a 2 D image across a swath 6 degrees in length by the scan distance and with an angular resolution Nyquist sampled of 1 7x10 0 mrad Both 1024 x 32 pixel and 512 x 8 pixel images will be taken depending on what specifically is being observed During the non imaging runs A ice shall observe a region on the target object for a period of 50 Rosetta ALICE User Manual time necessary to achieve the desired SNR for a chosen minimum radiance level After the 1024 x 32 pixel image is through accumulating the image may be collapsed spatially to a one dimensional spectrum 1x1024 pixels and stored for eventual transmission to the spacecraft d
118. n 1 SeHghVotapof r T 15 Set Heater On HB AE 9 f Set Heater of 20 sSetSmdaor n 21 27 Set Discriminator Level 23 PetomSefTe _ T 24 sSetPegam T 25 GetParmeers M 26 JT Multiple Acquire dump At Service 255 Common Private Telecommands Reset Telemetry Output Buffer c r 6 1 Telecommand Packet and Parameter Definitions Before accepting any telecommand packet Alice will verify the correct APID the declared length length field in the telecommand and the CRC for the received packet If any of these three checks fail the telecommand is not accepted and if requested by the acceptance acknowledgement header bit an appropriate telecommand acceptance failure telemetry packet 1 2 is generated The specific acceptance rules for the different telecommands are described with each telecommand definition If for a specific packet correct packet length is mentioned as an acceptance criteria this means that the length is compared to the expected length for this specific telecommand Telecommand Packet Definition Alice Packet Name Enable Disable Housekeeping Generation Packet Function enable disable instrument housekeeping output Verification Rules acceptance correct packet length and SID check executi
119. n Protoflight Model vil PHD POT PROM PS RTN S C SFT SIS SPT SVT SwRI TB TBC TBD TBR TC TM TRP TV URF UV VIRTIS WAC Pulse Height Distribution Pump Out Tube Programmable Read Only Memory Power Supply Return Spacecraft System Functional Test Spacecraft Interface Simulator Specific Performance Test System Validation Test Southwest Research Institute Thermal Balance To Be Confirmed To Be Determined To Be Resolved Thermocouple Telemetry Temperature Reference Point Thermal Vacuum Unit Reference Axes Ultraviolet Visible and Infrared Thermal Imaging Spectrometer Wide Angle Camera OSIRIS viii Rosetta ALICE User Manual 1 General Description 1 1 Alice Team Alan Stern PI SwRI astern boulder swri edu 1 303 546 9670 John Scherrer Pre launch Project Manager SwRI jscherrer swri org 1 210 522 3363 Joel Parker Post launch Project Manager SwRI joel boulder swri edu 1 303 546 9670 Dave Slater Poject Scientist SwRI dslater swri org 1 210 522 2205 Maarten Versteeg Lead Software Engineer SwRI mversteeg swri org 1 210 522 5029 Paul Feldman Science Team Member APL JHU pdf pha jhu edu 1 410 516 7339 Mike A Hearn Science Team Member U Maryland ma astro umd edu 1 301 405 6076 Jean Loup Bertaux Science Team Member Jean Loup Bertaux aerov jussieu fr 33 1 6920 3116 1 2 Scientific Objectives Alice EID B 5 1 1 1 The scientific objectives of the
120. n of Service 19 pressure and dust limit checks Along decontamination running only the optics heaters HV off AALS303A e Close aperture door AALS402A after sufficient time for cooling e Refresh all EEPROMS if necessary see Flight Rule EMP 3 e Power off AALS103A 3 2 3 2 In Flight Calibration In flight calibration sequences using hot UV stars shall take place periodically during the mission e g during the initial commissioning phase and during active checkouts and before after any observational campaign e g Earth fly by Mars flyby etc The set of UV stars chosen shall have been observed and calibrated for flux versus wavelength within the Alice UV passband with IUE The following shall be measured during these calibration runs e Effective area versus wavelength and spatial location along slit e Point spread function focus e Wavelength calibration e Pointing e Detector dark count rate e MCP pulse height distribution Trending of the above quantities shall also take place during the mission to identify and track changes in instrument performance For best trending the same set of UV stars shall be observed when possible during each in flight calibration run 3 2 4 Flight Operations Plans per Mission Phase Mission phases are described in the Rosetta Mission calendar document RO ESC TN 5026 Alice operations are note uniquely defined for each mission phase since each phase will have many similar components calibr
121. n sequence and finally an end to end Performance Aliveness Test PAT This last test verified the basic end to end electrical functionality of the Alice instrument Phase 2004 September 20 30 October 4 Phase III included a series of Activity Groups for scientific calibration and verification of the optical alignment between instruments on the Rosetta spacecraft Phase III started with the interference test Activity Group 14 defined by ESA to characterize possible interference between the different experiments on the Rosetta spacecraft Following the interference test two Activity Groups 15 16 were dedicated to the alignment measurements that determine the relative alignment of the different experiments on the spacecraft For Alice the alignment measurement determined the relative alignment of Alice with respect to OSIRIS and possibly other instruments For all alignment tests it was mandatory that OSIRIS was also active so the results of the Alice test could be compared with the science 46 Rosetta ALICE User Manual observations made by OSIRIS The final four Activity Groups 17 20 were dedicated to Alice science calibration Commissioning Activity Descriptions Descriptions of various activities that occurred during the Commissioning phase are described below They are written in the future tense as they were before commissioning began actual details of each flight commissioning activity can be found in Rosett
122. nal Test Procedure 8225 FTP 01 Rev 2 Attachment 4 Test Sequence Definitions for Alice Flight Software 8225 TEST DEF 01 Rev 1 Chg 1 Attachment 5 Alice End to End Radiometric Test S C Version 8225 ETE RAD SC 01 Attachment 6 Alice Detector Vacuum Pumpdown amp Backfill Procedure 8225 DET PUMPDOWN 01 Attachment 7 Commissioning Sequences for Alice 8225 COM SEQ 01 Attachment 8 Test Sequence Definitions for Alice System Validation Test 8225 SVT DEF 01 Attachment 9 Alice RSDB Summary 8225 RSDB SUM 01 8 10 Attachment 10 Alice EMI Waiver RO ALI RW 009 8 11 Attachment 11 Alice Hot UV Star List 8 12 Attachment 12 Alice In Flight Aperture Door Performance Test 96 Rosetta ALICE User Manual ATTACHMENT I PFM Mechanical Assembly Drawings 97 Rosetta ALICE User Manual ATTACHMENT 2 Alice Standard Sequences Templates Document 8225 STD SEQ 01 Rev 0 Chg 4 98 Rosetta ALICE User Manual ATTACHMENT 3 PFM Functional Test Procedure 8225 FTP 01 Rev 2 99 Rosetta ALICE User Manual ATTACHMENT 4 Test Sequence Definitions for Alice Flight Software 8225 TEST DEF 01 Rev 1 Chg 1 100 Rosetta ALICE User Manual ATTACHMENT 5 Alice End to End Radiometric Test S C Version 8225 ETE RAD 5 01 101 Rosetta ALICE User Manual ATTACHMENT 6 Alice Detector Vacuum Pumpdown amp Backfill Procedure 8225 DET PUMPDOWN 01 102 Rosetta ALICE User Manual ATTACHM
123. nded to operate in one of three data collection modes 1 image histogram ii pixel list and iii count rate modes Each of these modes uses the same 32k word 16 bit acquisition memory The first two acquisition modes use the same event data received from the detector electronics but the data is processed in a different way Also in these two modes events occurring in up to eight specific areas each area is composed of 128 spectral pixels by 4 spatial pixels that can only be positioned at a multiple of its size on the array can be excluded to isolate high count rate areas that would otherwise fill up the array The third acquisition mode only uses the number of events received in a given period of time no spectral or spatial information is used and hot pixel masking will not affect the acquired data Image Histogram Mode In this mode acquisition memory is used as a two dimensional array with a size corresponding to the spectral and spatial dimensions of the detector array The image histogram mode is the prime Alice data collection mode and the one most often used during flight During an acquisition event data from the detector electronics representing x y pixel coordinates are passed to the histogram memory in parallel form The parallel data stream of x and y values is used as an address for a 16 bit cell in the 1024 x 32 element histogram memory and a read increment write operation on the cell contents is performed for each event Durin
124. ndow upper 0 31 value of zero indicates an unused dump specification slot delay between generation of dump TM packets in kernel ticks 0 255 0 delay can be used to reduce Alice science data production rate Notes critical executes in the slow thread if test pattern is specified then the acquisition will be executed normally but Alice acquisition memory will be filled with a test pattern after completion of the acquisition 8 dump specifications 2772 Rosetta ALICE User Manual The time specified for the acquisition mode 1 is the maximum acquisition time the actual time may be shorter when the acquisition memory is filled before the acquisition time is exceeded Cycle time specifies the overall cycle duration in seconds start of a data acquisition will only start at the specified start time for the if a previous cycle has not been completed yet acquisition will remain idle until the next cycle start cycle time of zero specifies continuous acquire dump operation in which cycle time is determined by the duration of acquire and dump operations without any additional delays The acquisition interval for the CountRate acquisition mode is specified using a one byte number that specifies the time in units of 3 ms The duration in milliseconds is calculated from the byte value as 3 BV mod 32 24 BV div 32 This exponent and mantissa like use of the specification value results in a dynamic range of
125. ng where on the detector the event occurred It also produces a count of total events The difference between the modes is the way in which the data is stored Image Histogram mode In image histogram mode the event address that is generated by the detector electronics is used as an index into the acquisition memory The value at that memory location is then incremented The result over time is a histogram of the photon events received by the detector The value at each address in the acquisition memory indicates the intensity at that detector location The data storage operations in this mode are performed by hardware once configured by software The software only intervenes at the beginning and end of the acquisition or if a problem is detected The data dumped from the histogram mode once completed consists of part or all of the memory array The data may also be collapsed into bins as it is sent down to reduce overall data quantity the time required for this collapse is very short and does not add significant overhead operations Pixel list mode In pixel list mode the event addresses that are generated by the detector are stored sequentially in the memory array as ina list In addition to the detector events a time mark value is also inserted into the list on a periodic basis The result is a list of all detector events during the integration period along with the time binning information The data storage operations in this mode are per
126. nsigned 16 commanded total count AcaInterval unsigned 16 acquisition interval milli seconds fails calculated value is only a single byte in size and does not fill the telemetry field unsigned 16 Pktltems unsigned 16 Startltem unsigned 16 Data unsigned 16 list of N count rate items X max 3994 124 3870 octets gt 1935 words Notes Housekeeping data item is the same as data field of housekeeping data telemetry packet not including SID StartTime StopTime DumpNo SciSeq ez 313 Totalltems 88 Rosetta ALICE User Manual Parameter data item is the same as data field of context telemetry packet 18 2 Total packet length is variable depending on quantity of science data estimated overhead 124 octets remainder is count rate data up to 3870 octets 1935 items All of the packet fields from the beginning to the DetectorCounts field inclusive are common to all science data packets Telemetry Packet Definition Alice Packet Name Diagnostics Instrument Alice Packet Function Provide Alice non routine diagnostic data Generation Rules Periodic at same rate as housekeeping data whenenabled by parameter default is off Header Information Process ID Packet Catego 12 2 Service Type 0 Service Subtype 3 Structure ID Packet Length 0 data Data Field Information Data Field Field Structure Remarks SID enum 16 value 4 DgNextCycleTime time 48 calculated time for the sta
127. ntingency situations Memory patching for Alice is performed via the memory management service The available code space for the Alice flight software is 32 kbytes currently 98 7 of this code space is used in one large executable segment Unless local patches can be used to correct software functionality for instance to patch local variables in the code space a full memory patch may be needed Alice has two types of non volatile memory PROM and EEPROM These memory type share address space such that only one is accessible for execution at one time EEPROM is always accessible in data space When Alice hardware is booted code execution always starts from PROM This is where the Alice nominal flight software is stored There are available multiple pages of EEPROM that can be overlaid over the PROM Every EEPROM page will initially contain a copy of the nominal flight software If a patch becomes necessary one or more of these EEPROM pages will be modified as needed by using the memory service Then by use of a private telecommand Alice can be commanded to switch to execute from the patched EEPROM copy rather than the EEPROM If it becomes necessary to always operate Alice with a patched copy of the code then a modified startup OBCP can be used to always issue this command when Alice is started 20 Rosetta ALICE User Manual Note that since launch the Alice EEPROMS have been updated with new versions of the code so standard procedure is t
128. ntinuous purging with dry while on the spacecraft at a low purge rate of 2 L hr The purity of the GN should correspond to MIL P 27401C Grade C or better Interruptions of gas flow during spacecraft handling or servicing operations should not exceed 5 hours During spacecraft transport the flow may be stopped for up to 168 hours although the interior of Alice must remain in a dry environment during this time Additional Alice purging requirement details can be found in the Alice Contamination Control Plan SwRI 8225 01 3 2 2 In orbit Commissioning Plan The Alice commissioning activities were split into three separate phases as shown in Table 3 1 Each Phase was composed of a set of related test sequences called activity groups All the described sequences were stand alone entities that did not depend on the state at the end of a previous sequence Each sequence started with a power on of the Alice instrument and at the end of the sequence Alice was powered off 45 Rosetta ALICE User Manual Table 3 1 Alice Commissioning Phases Must be performed early in the mission to place Alice in a safe condition for flight Preferably to be performed early in the mission to obtain knowledge of Alice instrument health Phase III Scientific Functionality 14 20 Can be performed later in the mission but must occur prior to the Mars fly by Phases I and II represent the sequences and commissioning steps that Alice
129. ntrance slit the light falls onto a toroidal holographic grating where it is dispersed onto a microchannel plate MCP detector that uses a double delay line DDL readout scheme The 2 D 1024 x 32 pixel format MCP detector uses dual side by side solar blind photocathodes of potassium bromide KBr and cesium iodide CsI The predicted spectral resolving power of Alice is in the range of 70 170 for an extended source that fills the instantaneous field of view IFOV defined by the size of the entrance slit Alice is controlled by an SA 3865 microprocessor and utilizes lightweight compact surface mount electronics to support the science detector as well as the instrument support and interface electronics Figure 1 3 2 shows a three dimensional external view of Alice a photograph of the Alice protoflight model PFM is shown in Figure 1 3 3 The resulting design is highly systems engineered to minimize mass and complexity and enjoys strong parts level heritage from previous UV spectrometers A simple block diagram of the Alice electronics is shown in Figure 1 3 4 Detector Electronics C amp DH DDL Detector Electronics TT Detector Door 146 mm OAP Mirror High Voltage Power Supply Entrance Aperture Door Figure 1 3 1 The opto mechanical layout of Alice 11 Rosetta ALICE User Manual C amp DH Electronics Connector Detector Electronics Purge Connector Entrance Aperture Figure 1 3 2 Extern
130. nuclear maps at Nyquist sampled resolutions of a few hundred meters Stars occulted by the absorbing coma will also be observed and used to map the water molecule spatial distribution giving us hints at how the production regions are located on the nuclear surface A summary of the Alice performance capabilities is given in Table 1 1 Through its remote sensing nature Alice will be able to e Obtain compositional and morphological information on the comet prior to the rendezvous thereby providing planning observations for in situ instruments prior to entering orbit about the comet e the spatial distribution of key species in the coma and small coma dust grains as a function of time as the comet responds to the changing solar radiation field during its approach to the Sun e Obtain compositional and production rate measurements of nuclear jets and other inner coma features even when the orbiter is not in the vicinity of these structures Obtain certain ion abundance measurements around perihelion in order to connect nucleus activity to changes in tail morphology and structure and coupling to the solar wind The primary scientific themes of the Alice investigation are the following not prioritized 9 Rosetta ALICE User Manual Determine the rare gas content of the nucleus to provide information on the temperature of formation and the thermal history of the comet since its formation Ar and Ne will be prime targets of the A
131. o be necessary 12 HIBERNATION HIB HIB 1 Prerequisites i Hibernation operations shall be preceded by the PM s written confirmation that the EEPROM memory and Parameter List are all suitable for post hibernation power up ii A 16 hr heater decontamination cycle shall have been completed lt 16 hours before entering hibernation iii The Aperture Door shall be successfully closed and verified iv The HV set point for use during normal acquisition operations should be changed to a low i e safe value before entering hibernation HIB 2 Configuration Alice shall be configured as follows i HV off ii Aperture door closed Gii LV off Flight rules marked by a dagger were one time operations performed during instrument Commissioning activities they are no longer applicable 54 Rosetta ALICE User Manual 3 3 Failure Detection and Recovery Strategy The Alice instrument is a single string instrument Accordingly there is little that can be done in the event of a major system e g HVPS vacuum door etc failure Table 3 2 summarizes the possible failure modes and describes the consequences of each See the Alice Failure Modes Criticality Analysis for a detailed discussion of possible spacecraft interface failure modes and their consequences Table 3 2 Alice Failure Modes amp Possible Recovery Operations Detector Vacuum Failure to Open Operation with the detector vacuum door closed results
132. o operate Alice from EEPROM not PROM except for special cases such as software updates For more information on the current and previous version of the flight software code see Sections 2 3 5 and 3 1 11 Alice also supports dumping and checksumming of memory again via the memory management service memory dump would only be performed in an extreme situation where there was no other way to diagnose a problem Memory checksumming may be used to occasionally verify the contents of code memory or to verify proper loading of a patch The addressable non volatile memory size is 32 kbytes As described above this memory space can be overlaid with PROM the default or one of four EEPROM memory pages The entire Alice program must fit within the 32k limit The available data memory size is 32 kbytes In addition Alice also has memory mapped I O and control registers and a paged window for access to the 64 kbyte acquisition memory The Alice memory map is shown in Figure 2 3 1 Code Space Data Space PROM shadows EEPROM when MEMCTL 6 0 Detector Memory 32K page EEPROM 32K page 4000 4FFF yo 7000 7FFF unused 5000 EEPROM 8K page EEPROM page selected by MEMCTL 1 0 pages 0 3 128K 6FFF RAM 32K present in all mappings Figure 2 3 1 Alice memory map Detector page selected by DMCR 1 0 pages 0 3 64K bit 15 time hack bits14 10 spatial bits 9 0 spectral EEPROM page selected
133. ock 0 0 The telecommand interface circuit and the telemetry interface circuit are shown in Figure 2 2 2 and Figure 2 2 3 respectively 16 Rosetta ALICE User Manual CLK Prime CLK Prime Mem Load Prime Mem Load Prime Enable Prime Enable Prime Enable Redundant Enable Redundant Mem Load Redundant Mem Load Redundant CLK Redundant Redundant 000869 FROM MICRO CONTROLLER ALT RECEIVE SHIFT REGISTER CIRCUIT EID A ALT RECEIVE CIRCUIT EID A ALT RECEIVE DIN7 16K x 9 FIFO DINO DOUTO DOUT7 1 1 1 1 1 Enable Prime COMMAND CLK Prime INPUT STATE ALT i MACHINE amp RECEIVE Enable Redundant STUCK BIT CIRCUIT CLK Redundant REMOVAL 2 Sec EID A S M Clock COUNTER gt RST CNTL gt CMD CHANNEL EDAC WATCHDOG CALCULATION CIRCUIT EID A SHIFT REGISTER DATA OUT 16K x 9 FIFO DINO DOUTO DIN DOUT7 PRIME ALTERNATE RECEIVE TELEMERTY OUTPUT STATE MACHINE AND STUCK BIT REMOVAL Shift Register Do D15 CIRCUIT EID A PRIME ALTERNATE ENABLE RECEIVE
134. od is not used in the current Lima program 3 1 7 3 Count Rate Acquisition For a count rate acquisition the number of counts per sample slot is specified Exactly this number of slots will be acquired unless the end of the acquisition buffer is reached first The check for the end of the acquisition is performed once every second so the actual reported acquisition end time may be up to one second after the actual acquisition completion although different from the pixel list acquisition no additional data will be stored The acquisition duration and a more accurate estimate of the end time can also be determined by calculating the duration from the number of acquired slots and the interval note that this method is not used in the current Lima program 3 1 8 Analog versus Digital Detector Count Rates and Rate Doubling The Alice instrument detector includes two separate data paths through which the events are reported The primary path is the digital event interface through which the C amp DH receives the detected photon event spectral location spatial location and pulse amplitude as a 19 bit digital word For monitoring purposes a second path is used that only reports the fact that a photon is detected by the detector this is the raw analog event The second path may report a higher number of events when the processing of the digital data cannot keep up with the photon events but this only comes into effect for extremely high count rates
135. of Alice and a photograph of the flight unit 3 1 2 Optical Design The mirror has a clear aperture of 41 x 65 mm and is housed in the telescope section of the instrument The reflected light from the OAP enters the spectrograph section which contains a toroidal holographic grating and MCP detector The slit grating and detector are all arranged on a 0 15 m diameter normal incidence Rowland circle 34 Rosetta ALICE User Manual Pinhole 1 0mm o 0 47 deg 3 26 mm 1 53 deg 12 78 mm 4 26 mm 2 0 deg 3 0 deg gt 4 040 4 0 025 deg 0 21 mm 0 05 deg 1 53 deg 2 0 deg 2 0 deg 35 degrees up from the recenw 5 bottom is row 15 ro s C X axis as imaged by Alice b Figure 3 1 1 The Alice entrance slit design a The physical dimensions of the slit b The slit orientation with respect to the DDL detector image spatial axis and the spacecraft axes The spectrograph utilizes the first diffraction order throughout the 700 2050 spectral passband The lower half of the first order wavelength coverage 700 1025 also shows up in second order between the first order wavelengths of 1400 and 2050 Both the OAP and grating and their mounting fixtures are constructed from monolithic pieces of Al coated with electroless Ni and polished using low scatter polishing techniques The OAP and grating optical s
136. on always Header Information Process ID 12 Service Type 3 Service Subtype 5 6 seenotes Structure ID Data Field SID structure identifier of HK type always 1 for Alice Notes Sub type 5 enables the specified SID sub type 6 disables the specified SID Alice only has one HK SID 71 Alice HK is disabled at startup but Alice will when not enabled earlier enable HK generation 40 seconds after startup and start generating HK packets Telecommand Packet Definition Alice Packet Name Load Memory Instrument Alice Verification Rules acceptance memlength consistent with packet length valid writable memory ID PROM can t be written to one block specified code executed from PROM when loading EEPROM detector memory specification does not cross 16k byte page boundary EEPROM memory specification does not cross 128 byte block border and instrument state is checkout execution always Header Information Process ID Packet Category 12 Service Type Service Subtype Structure ID Packet Length Data Field Information 66 Rosetta ALICE User Manual MemLength this field is repeated for the number of words specified by MemLength Notes Memory types Memoryld defined in memory dump telemetry packet 6 6 Only single block load packets are supported Packet data field length is 8 MemLength 2 Telecommand Packet Definition Alice Packet Name Dump Memory Packet Function Verification Rules acceptance correct
137. on commanded for 1000 seconds may last up to 10 seconds longer and during that reported time the actual acquisition will have been active The variation between individual 1000 second histogram acquisitions will probably be less as the check periods are based on a fixed check interval that is started at the beginning of the acquisition but this is also determined by other tasks execution times within the software 3 1 7 2 Pixel List Acquisition For a pixel list acquisition the completion condition end time or number of counts is checked every second For a time limited pixel list acquisition this means that the duration of the acquisition can be up to one second longer than commanded and additional events hacks and real events will be captured during this period For a count limited pixel list acquisition this means that for one second after reaching the commanded event count hacks and real events more events may be accumulated In any case the acquisition will always terminate when the end of the acquisition buffer is reached but also in that case the recorded end time may be up to 1 second after the actual event 0 2 seconds after the event for software version 2 05 A more accurate estimate of the end acquisition time and the acquisition duration can be determined by using the time hacks embedded in the acquired pixel list In that case the accuracy of the acquisition end time is determined by the selected hack rate note that this meth
138. on to the functional extension of the software some small changes corrections were made to correct earlier found problems e SPR 19 Door Life Test writes beyond result buffer was corrected e SPR 20 PAD field not copied for service 1 responses was corrected 2 3 6 Boot Sequence When Alice is started it carries out the following boot sequence 1 Run internal startup self test about 20 seconds Enter safe state Transmit power on event packet Wait for 40 seconds or enable HK command Send first HK packet ERO COS Continue sending HK at default rate During the time of the self test approximately 20 seconds after power on Alice will not accept any telecommands Once Alice sends the power on event packet it is then capable of receiving telecommands If an enable HK telecommand is sent then Alice will begin generating housekeeping data right away If no enable HK telecommand is received then HK will be automatically enabled 40 seconds after the power on event packet was sent Normally Alice expects to receive a time update shortly after completion of the power up self test but this does not affect the boot sequence or timing only the time tagging of telemetry If Alice is turned off then a duration of at least I second should be observed prior to turning Alice back on to allow for hardware discharge time 24 Rosetta ALICE User Manual 2 3 7 Instrument Operating Modes To avoid confusion first it
139. over closed e Detector wavelength cal and focus check using GSE Pt stim lamp at entrance aperture 1800 to 2050 interior of instrument under GN purge e Microprocessor software checkout with flight like sequence e Environmental Tests after each test below a limited electrical functional test is performed e EMI EMC tests e Random vibration tests Acoustic vibration tests e Thermal vacuum tests e Post environmental Functional Tests same as the pre environmental functional tests listed above e Final optical alignment check Alice can be fully verified and tested on the bench and on the Rosetta spacecraft This is possible because the detector can be pumped down to a safe operational vacuum level 8 x 10 Torr using the GSE vacuum pump cart and GSE vac ion pump hardware Full functionality and optical alignment can be 44 Rosetta ALICE User Manual verified without opening either the detector or front aperture doors The detector door is equipped with a window that transmits UV light at wavelengths gt 1200 A the front aperture door is equipped with a removable plug in its center that can be taken out during ground test to allow light to enter the instrument This removable plug is a flight item it will be installed for flight a green tag attach before flight item The detector door is a one time operation in flight It will never be opened during S C ground integration and test activities During ben
140. pdated when a test is commanded using the Perform Self test command initially this field will show the value 0x10 Telemetry Packet Definition Alice Header Information ServiceType TS Service Subtype 1 Data Field Information Data Field Remarks EID value 40001 unused EvDoorPos enum 2 door position 0 error 1 closed 2 opened 3 in between 81 Rosetta ALICE User Manual Telemetry Packet Definition Alice Header Information PrcessIDD 92 Cs PacketCategoy 7 ServiceType 5 m 3 J4 J J SerwieSupe 2 Data Field Information Data Field EID EvDoorSet enum 2 expected door position 1 closed 2 open P e quused EvDoorPos enum 2 actual door position 0 error 1 closed 2 opened 3 in between Telemetry Packet Definition Alice Header Information Process ID J92 PacketCategory 7 ServiceType 5 m SewieSutype Ji Data Field Information Data Field EID EvHvSet EvHvOn Notes This event is generated whenever the internal setpoint for the high voltage is changed It does not reflect actual high voltage only the set point The HVPS can be commanded to a set point of 0 and be on so the HvOn bit indicates if the supply is commanded on or off in addition to the set point Packet Name Parameter read warning event Alice Packet Function Generation Rules Process ID Packet Category Service Type Str
141. pends on value of EvSafetyld dust dust flux value bright detector count rate pres trend pressure rate pres alert triggering pressure HVPS value of erroneous check low 8 bits and current McpSetpoint upper 8 bits temperature ADC temperature value Notes The severity is configurable by parameter PmEventSafety and is either ground sub type 3 or on board sub type 4 This packet is only generated each time the safety status changes to a less safe condition whenever a new condition is triggered If multiple conditions occur at the same time then only one is indicated Telemetry Packet Definition Alice Alice 83 Rosetta ALICE User Manual 40007 Data Field Information Remarks value 40007 simple checksum calculated during startup of code memo EvStartupInfo bool 1 rtx clock test results of the power on self test 1 test failed tests idenditcal bool 1 fine clock to the test executed in response to the Self Test command 192 23 bool 1 RAM memory bool 1 acq page switch bool 1 memory 3 bool 1 memory 2 bool 1 memory 1 Notes Generated when Alice is turned on or if Alice resets such as a watchdog timeout The Info field contains information about the startup such as a self test report Note that since this packet is produced automatically when Alice is started the packet time field will generally contain unsynchronized time Telemetry Packet Definition Alic
142. peration of the flight software is discovered a new flight software version will be produced This will consist of a new 32 kbyte code image After test and verification such a new software release will be documented in a new release of the Flight Software Document Another need for a code memory patch could be failure of certain locations of the RAM memory The RAM memory map is fixed in the flight software but a new memory map could be used to create a new version of the flight software that avoids using the affected locations Depending on the changes different strategies may be followed to upload such new code into one of the EEPROM memory pages of the instrument If the number of changes is limited only the changes from the version of the software in the target EEPROM page may be loaded otherwise a complete 32 kbyte code upload package will have to be produced The full 32 kbyte code upload would result in a total of 256 memory load telecommands Initially code changes would be made to the last page EEPROM 3 of the EEPROM memory keeping the first three pages as backup of the current version of the flight code if the startup check algorithm detects a problem it will successively check the EEPROM pages for correct code starting at the first page so the patched page will be the last one to be checked if the others are damaged this way patched code is less likely to be prematurely run If only a one time patch is needed to the code e g to
143. performed mostly independent of the other Rosetta instruments Phase I consisted of seven Activity Groups that were essential to bring Alice into a safe configuration and which were used to prepare Alice for subsequent commissioning sequences Phase II consisted of six activity groups that performed a basic electrical functional verification of the instrument Phase III consisted of scientific calibration and verification of the optical alignment with the other Rosetta instruments Phase I 2004 March 22 23 April 15 20 The first three Activity Groups 1 3 verified basic communication functionality unlatched the aperture door and verified correct operation of the aperture door Also the ROSINA and GIADA based safety mechanisms were verified Activity Groups 4 to 6 mainly consisted of optical decontamination sequences of the instrument long periods were spent with the aperture door open and the mirror and grating heaters on to enable outgassing of the Alice instrument The last Activity Group 7 in this Phase opened the detector door Phase 2004 April 20 22 May 28 29 Phase II is started with three Activity Groups 8 10 dedicated to verification of the basic detector operations and a continuation of the instrument decontamination procedure Activity Groups 11 and 12 concluded this initial phase of the Alice in flight commissioning with a verification of the functionality of the various acquisition modes and operations a decontaminatio
144. quireDump telecommand Depending on the specific configuration of timeout period number of acquisition cycles and cycle timing this mechanism may be used to implement a strategy that weights instrument safety versus science return During the mission this strategy may change from very cautious to more aggressive when the instrument becomes better known 2 3 3 Software Maintenance Approach There are two ways to access and modify Alice software changes to the parameter file and patching of the code memory in EEPROM as described below All of Alice important operating parameters are kept in a parameter file which is an area of memory which holds constants and parameters used by the software The contents of the parameter file are shown in the context packet definition They can then be changed at any time by command Each time Alice is shut down normally the entire parameter file is saved to the spacecraft using the context service Whenever Alice is started the default contents of the parameter file are loaded from ROM In the nominal startup sequence Alice will receive the most recent parameter file from the spacecraft via the context service This is the normal way that Alice software is modified during the mission This type of modification qualifies as a level I change according to EID A Section 6 5 3 The second way that Alice software can be changed is through a memory patch This qualifies as a level 3 change and would only occur in co
145. read only one slow telecommand can execute at a time 68 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Accept Context Packet Function load internal parameter file instrument context Verification Rules acceptance correct packet length execution always Header Information Process ID 92 Packet Catego Service Type 18 Structure ID N A 2 data Data Field Information Data Field Remarks context see notes Notes Data field contents same as context report 18 2 This telecommand executes in the slow thread Telecommand Packet Definition Alice Packet Name ROSINA pressure distribution Packet Function provide ROSINA pressure to Alice Verification Rules acceptance correct packet length execution always Header Information Data Field Information Notes This packet is part of the information distribution service provided by the spacecraft Alice needs this information for its internal safety procedures The special real format has 4 bit mantissa with range of 1 9 and 4 bit negative exponent from 0 15 Telecommand Packet Definition Alice Packet Name ROSINA pressure alert Alice Packet Function provide ROSINA pressure alert Verification Rules acceptance correct packet length execution always Header Information Process ID 12 Service Type 11 Structure ID 2 data Data Field see notes Notes This packet is identical to Rosina pressure distribution 19 10 except that it
146. retains the door closed against the aperture stop baffle at the bottom of the stop The door is activated to open when the latch pin is retracted via the firing of a dimple motor via command to the spacecraft interface to the dimple motor The spring attached to the door is then free to pull the door into the open position In the open position the fail safe door lies flush against the bottom floor of the instrument housing Opening the fail safe door is a critical command The peak current draw during the fail safe door opening is 4 Amps over a 10 millisecond period 3 2 Operating Modes 3 2 1 Ground Test Plan from Alice EID B 5 The Alice PFM requires very little by way of ground operations facilities or personnel With its flight detector sealed internally and the detector vacuum verified by the ion pump current the instrument is safe to operate at one atmosphere Cleanliness precautions do need to be taken to prevent contamination of the optics A dry nitrogen purge must be maintained on the instrument when it is not stored in its shipping container After integrating Alice to the spacecraft the following tests shall be performed e Optical alignment e Pre environmental Functional Tests e End to end Command Data Handling Tests uplink commands TM interface checks downlink of HK data channels e Decontamination heater checkout e Dimple motor firing test per procedure 8225 DIMP 01 e Detector dark count test internal c
147. ribed in Attachment 7 Technical Note 8225 COM SEQ 01 Commissioning Sequences for Alice and Section 3 2 3 1 Note that passive checkouts originally were referred to as 6 month checkouts but the timing and nomenclature changed 3 24 3 Earth Swing by There are three Earth Swing bys March 2005 November 2007 and November 2009 Earth Swing by observations provide the only opportunity for particular in flight calibrations of the Alice instrument The Moon is the only object that can provide 1 a large bright and uniformly illuminated source for a filled slit flat field 11 an absolute solar flux calibration particularly for the short wavelength 912 regime of the Alice passband and iii an extended object scattered light evaluation Operations will include exposures in all acquisition modes using both fixed and scanning pointing 3 2 4 4 Mars Swing by There is one Mars Swing by February 2007 Alice will produce the first Mars EUV dataset ever obtained at Mars and the highest ever EUV spatial resolution Operations will include dayglow nightglow and auroral observations stellar occultation observations to study the Martian atmosphere The Rosetta Mars Swing by will coincide with the New Horizons flyby of Jupiter so Alice can also observe Jupiter during this phase to provide large scale data in support of Jovian magnetotail aurora and Io Plasma Torus studies Operations will include exposures in histogram and pixel list
148. ription Location Contro RMIBID Bewenene OO OAP Mirror Thermistor 2 HkMirrorTempSec OAP Mirror Bracket Alice NALD1002 3 Grating Thermistor 2 HkGratingTempSec Grating Bracket Alice NALD1201 ScAliceTempReference 1 NTSAO0068 Instrument Housing Thermistor 2 ScAliceTempReference 2 Instrument Mounting Foot 5 NTSA0188 Discriminator level readback HkDiscriminator C amp DH Electronics NALD1301 Operating State HkOperatingState C amp DH Electronics NALDO0107 2 3 Software DRD 28 1 This section of the document contains a description of the A ice instrument Flight Software AFS A detailed description of the Telemetry and Telecommand formats can be found in Section 6 2 3 4 Software Overview The Alice Flight Software AFS controls the Alice instrument AFS controls and monitors the instrument hardware and communicates with the spacecraft through the telecommand and telemetry interfaces AFS executes on an 8051 compatible microcontroller Because the microcontroller runs at a low frequency to save power AFS is designed to be as simple as possible As much as possible the hardware has been designed to handle processing related to data acquisition and packet buffering in order to reduce the computing load on the microcontroller 18 Rosetta ALICE User Manual Because of the simple design Alice software can only perform one function at a time Therefore
149. rogress of the current Multiple Acquire Dump command 0 free no Multiple Acquire Dump command active 1 init Multiple Acquire Dump processin started 2 loop started the main loop of the Multiple Acquire Dump cycle 3 wait waiting until it is time to start the acquire phase of the Multiple Acquire Dump cycle 4 5 DgTotalSent count of total packet transmitted f safe acquisition phase skipped because of active unmasked safety condition mode acquisition acquiring data in the specified mode 0 3 see specification of Multiple Acquire Dump telecommand 10 spec dump executing one of the specified data dumps 0 7 see specification of Multiple Acquire Dump telecommand The DgTaskStack indicates the current value of the stack pointer of each of the 10 tasks active in the Alice Flight Software tskMain tskDetector TskHvps tskSafety tskTclf tskTmIf tskDoor tskHk tskHeater and tskSlowTc This list also specifes the tasknumber as used to indicate the first deleted task as reported in the DgFirstDeleted parameter Telemetry Packet Definition Alice Packet Name Parameter Dump 89 Rosetta ALICE User Manual Generation Rules Header Information Process ID 12 Service Type Structure ID 44 data Data Field Information Data Field Field Structure Remarks enum 16 value 5 ParmData unsigned 8 40 configuration data context see notes Notes ParmData field has the same content and format as the context packet 18 2 6
150. rt analog housekeeping data to digital data for inclusion into the TM data stream and viii on board data handling Telemetry Command Interface Electronics The C amp DH utilizes radiation tolerant buffers and FIFO memory elements in the construction of the spacecraft telemetry and command interfaces A finite state machine programmed into a radiation hardened Actel 1280 FPGA controls the receipt and transmission of data A bit serial interface is used Decontamination Heater System A single decontamination heater each 1 W resistive heater is bonded to the backside surface of both the OAP mirror substrate and the grating substrate Along with each heater two redundant thermistors are also mounted to the back of each substrate to monitor and provide control feedback to the heaters The C amp DH electronics can separately control each heater Successful heater activations have already taken place during the commissioning phase of the flight Additional activations are planned periodically during the long cruise phase to comet 67P CG High Voltage Power Supply The HVPS is located in a separate enclosed bay behind the OAP mirror see Figure 1 It provides the 4 0 kV required to operate the detector The voltage to the Z stack is fully programmable by command in 25 V steps between 1 7 and 6 1 The mass of the supply 18 120 g and consumes a maximum of 0 65 W during detector operation 3 1 6 Data Collection Modes Alice can be comma
151. rt of the next acquisition cycle updated after the completion of the dump phase DgTotalCycles total number of commanded Multiple Acquire Dump Cycles DgTaskStack 10 unsigned 8 value of stack pointer for all 10 active AFS tasks DgMinFreeStack unsigned 8 minimum amount of free stack space detected during the last HK Diagnostics reporting period DgFirstDeleted task number of the first deleted task 0 9 set to 10 if no deleted task exists DgAcqPtrPL unsigned 16 memory pointer for Pixel List acquisition h w DgAcqPtrCR memory pointer for Count Rate acquisition s w SE DgPhaseMAD enum 8 current MAD execution phase includes acquisition type when active and dump cycle when active DgPressLimitTime time 48 calculated time at which the pressure limit would be reached based on Rosina reported pressure and trend DgRejectedSmall count of tm interface rejected small packets DgRejectedLarge unsigned 16 count of tm interface rejected large packets count of passes through idle loop in monitoring cycle Notes This packet is produced on a periodic basis with housekeeping data 3 25 if science output is enabled and the parameter PmDiagEnable is set to a non zero value The data in this packet is strictly for engineering evaluation of performance and for diagnostic purposes It has no scientific value and does not need to be interpreted on board or by the science data processing system The DgPhaseMAD parameter indicates the p
152. self test functions takes a total of about 20 seconds Packet Name Alice Packet Function execution always after confirmation see notes Process ID 12 Service Type 24 Structure ID 4 data Data Field Information Data Field Remarks 4 unused MemConfig new value for memory configuration see notes StartAddr Notes critical Memory configuration definition is per the memory control register 0x00 PROM 0x40 EEPROMO 0x41 EEPROM1 0x42 EEPROM2 0x43 and 0x43 EEPROM3 Telecommand loads new configuration value into EEPROM map register then begins executing at the specified address Unless the started code eventually executes a proper return from subroutine possible requested the execution acknowledge is lost it will only be generated after the sub routine completes 76 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Get parameter file Alice Packet Function causes dump of instrument parameter file 20 3 SID 5 Verification Rules acceptance always execution always Header Information Process ID 92 Packet Catego 12 Service Type 192 Service Subtype 25 Structure ID N A Packet Length 0 data Data Field Information Data Field Field Structure Remarks Notes Contents of parameter file will be dumped as science packet 20 3 SID 5 Executes in the slow thread Telecommand Packet Definition Alice Packet Name Multiple Acquire Dump Packet Function specifies Al
153. set Header Information Process ID Packet Category Service Type Service Subtype Structure ID Packet Length data Data Field Information i Field Structure Remarks TcPacketld unsigned 16 Packet ID field from telecommand equence unsigned 16 Packet sequence field from telecommand Alice on rejection of telecommand with acceptance acknowledge header bit set Packet Catego or 12 data 78 Rosetta ALICE User Manual Data Field Information Data Field Remarks TcPacketld unsigned 16 Packet ID field from telecommand TcSequence ailureCode Parm1 Parm2 Parm3 Parm4 Notes values for FailureCode and Parm3 and Parm4 shown below 4 invalid command code 0 0 b statuseror instrument state lower 3 bits Jo 6 data field error Telemetry Packet Definition Alice Packet Name Telecommand Execution Success Alice Packet Function acknowledge successful execution of telecommand Generation Rules successful completion of execution of telecommand with execution acknowledge header bit set Process ID Packet Category Service Type Structure ID ata Data Field TcPacketld unsigned 16 Telemetry Packet Definition Alice Packet Name Telecommand Execution Failure Alice Packet Function indicate execution failure of telecommand Generation Rules erroneous completion of execution of telecommand with execution acknowledge header bit set Process ID Packet Catego Service Type
154. signed 32 memory starting address of this block word address MemLength number of words in block MemData unsigned 16 memory data must always be even number of bytes this field is MemLength repeated for the number of words specified by MemLength 84 Rosetta ALICE User Manual Maximum dump words per packet is 512 1024 octets A single dump can be spread over multiple packets The following table shows the memory ID types for Alice note decimal number read onl EEPROM r w 00000000 0000FFFF Detector r w 00000000 00007FFF Data Memory r w 00000000 00007FFF Telemetry Packet Definition Alice Packet Name Memory Check Alice Packet Function produce memory checksum Generation Rules when solicited by check memory TC 6 9 Process ID Packet Catego Service Type 6 Senice Subtype O Structure ID data enum 8 see notes MemCheck unsigned 16 checksum of memory block see notes Notes the memory types Memoryld field is the same as the memory dump packet 6 6 the checksum method is 8 bit XOR rotate Telemetry Packet Definition Alice Packet Name Connection Test Report Alice Packet Function Generation Rules Process ID Service Type Structure ID data Data Field Notes Telemetry Packet Definition Alice Packet Name Context report Alice Packet Function provide Alice context report Generation Rules when solicited by report context TC 18 1 Process ID Packet Catego Service Type
155. specification of a number of identical cycles So after a single telecommand Alice will execute a specified number of the specified identical acquisition dump cycles This corresponds to the nominal planned science operations which consist of a series of acquisitions using the same acquisition and dump parameters Parameters will allow for the specification of e number of cycles e time between cycle starts or near continuous operation As Alice only produces science data on specific request the enable and disable science telecommands are non functional In case of a problem the private telecommand StopAcquire can be used to terminate any ongoing Alice science activity This will also stop any science data dumps at the next available telemetry packet boundary The acquired science data remains in the Alice internal memory and can be retrieved later using a separate dump action In the next two tables Table 2 10 and Table 2 11 the science data production volumes are summarised The first table specifies the base data volumes for each of the acquisition modes these assume a full dump of all acquired data the variations are the result of the different amounts of ancillary data that is included in each science dump This table also lists the factors contributing to possible limitations in the base volume The second table presents some more detail concerning the effect that mostly dump selection parameters have on the produced data amounts Tab
156. t can be raised by changing a parameter If it is determined that the temperature sensor is truly indicating some kind of overheating in the instrument then A ice will be shut down while an alternate operating strategy is devised Such strategy could include reducing the amount of time that A ice is powered in order to reduce heating Dust level safety condition alert If the reported dust flux exceeds a certain limit then a dust alert safety condition will be in effect and Alice will be safed A safety event telemetry packet will be produced A determination will be made whether or not the reported dust flux value is correct If so then normal operation will resume when the dust level drops to a safe value If the dust level reported is determined to be in error then Alice will be reconfigured to ignore the reported dust level Pressure safety condition trend or alert If the reported pressure level or pressure trend calculation exceeds a certain limit then a pressure safety condition will be in effect and A ice will be safed A safety event telemetry packet will be produced A determination will be made whether or not the reported pressure value is correct If so then normal operation will resume when the pressure level drops to a safe value If the pressure level reported is determined to be in error then A ice will be reconfigured to ignore the reported pressure level Bright object safety condition If the detector count rat
157. t control software The S C will be controlled from ESOC It will be conducted upon completion of the full system level verification program prior to S C shipment to the launch site Table 5 1 PFM Ground Test Sequences Verification Test Matrix Test Type Applicable Test Procedure s Alice HV Level When in Test Program BT 8225 FTP 01 250 V Post Alice delivery to Alenia 8225 FTP 01 UFT 8225 TEST DEF 01 s Post Alice integration to S C Post Alice integration to S C Post major S C transport S C EMI EMC tests Post S C vibration tests IST 8225 TEST DEF 01 0 V During the EMI EMC IST test Alice will be powered on and the Alice HVPS will be commanded to the low HV level of 250 V 60 Rosetta ALICE User Manual Test Type Applicable Test Procedure s Alice HV Level When in AIV Test Program Post S C TB TV tests Pre shipment to launch site MST N A 0 S C SFT operational phases Post Alice delivery to Alenia 8225 ETE RAD SC 01 41 kV Post Alice integration to S C SPT 8225 DET PUMPDOWN 01 full operational Post S C vibration tests 8225 TEST DEF 01 level Pre S C shipment to launch site Post S C acoustic shock tests AFT 8225 TEST DEF 01 During S C tests Post local S C movement SVT 8225 5 DEF 01 0V Pre S C shipment to launch site The HVPS will be commanded to 250 V in the IST run
158. t packet is generated when the door moves 5 1 This should be used in combination with the housekeeping packet 3 25 to confirm the actual successful motion of the door 74 Rosetta ALICE User Manual Telecommand Packet Definition Alice Packet Name Close aperture door Alice Packet Function closes the aperture door Verification Rules acceptance always execution always Header Information Process ID 92 Packet Catego 12 Service Type 192 Service Subtype 15 Structure ID N A Packet Length 0 data Data Field Information Data Field Field Structure emarks Telecommand Packet Definition Alice Packet Name High voltage on Packet Function turns on high voltage and sets level Verification Rules acceptance must be in checkout state execution must still be in checkout state so no safety condition active after confirmation Header Information Process ID 92 12 Service Type 192 16 Structure ID N A 2 data Data Field Information Remarks po wBy unused high voltage level DAC units Notes critical Since this is critical telecommand there can be a time delay between acceptance and execution Therefore the state is checked for acceptance and again for execution It is possible that the telecommand could be accepted but not executed if the state changes before execution Furthermore an execution success means that the HVPS has successfully been commanded to the new level It does not mean that it has
159. t so the measured operation times will also be different A test sequence was defined that performed door operations with the same timing as the door life measurement that was performed on the instrument The test was allowed to run for about 4 hours but no trend was observed in the door measurements STB door test 11 01 2004 timing identical to FM Se Sd Sc Sc 34 9 90 94 90 S60 34 90 90 S6 9 90 96 90 9456 50 50 50 90 90 80 90 open start duration ms open end 2 close start 3 close end Below we show the plot of all aperture door performance tests that have run since launch through passive checkout PC3 1 i j M 10
160. te This was easily achieved by physically masking the MCP active area where the H I Lyman a emission comes to a focus during the photocathode deposition process The bare MCP glass has a quantum efficiency about 10 times less than that of KBr at 1216 A Surrounding the detector tube body is the vacuum chamber housing made of aluminum and stainless steel As mentioned above this vacuum chamber protected the KBr and CsI photocathodes against damage from moisture exposure during ground handling and from outgassing constituents during the early stages of the flight It also allowed the detector to remain under vacuum lt 10 Torr during ground operations testing and handling and transportation Light enters the detector vacuum chamber through an openable door which contains a built in window port that transmits UV light at wavelengths gt 1200 A This window allowed testing of the detector with the door closed and provided redundancy during flight if the door mechanism had failed to open The detector vacuum chamber door was opened using a torsion spring released by a dual redundant pyrotechnic actuator dimple motor During instrument integration and test I amp T the door was successfully opened numerous times and manually reset In flight the detector was successfully opened however the primary side of the actuator did not open the door the redundant side was required to successfully open the door The detector electronics in
161. technic prime and redundant Interface Connector Electro Explosive Devices Pyrotechnic Initiators All pyrotechnic interfaces are implemented using the model 1 1130 dimple actuator manufactured by Eagle Picher Technologies This initiator has the characteristics outlined in Table 2 5 1 2 in the Alice EID B and meets the requirements outlined in EID A Section 2 5 Redundant connections between the spacecraft pyrotechnic interface connector and each initiator ensure that a single failure will not prevent the initiators from activating See the Alice MICD Attachment 1 for the location of these actuators Safety The Alice program will provide a plug for insertion into the spacecraft pyrotechnic connector that contains the ESD and dummy load resistors required by EID A Section 2 5 1 2 This plug will stay attached at all times except when the Alice instrument is mated to the spacecraft harness and will prevent accidental actuation of the device 2 2 3 OBDH Interface Circuits Alice EID B 8 2 7 The Alice instrument interfaces to the spacecraft OBDH as outlined in Table 2 4 The interfaces listed are compliant with EID A Section 2 7 Table 2 4 Alice OBDH Interface Channels Functions Telecommand Channels Memory Load Commands16 1 1 High Power ON OFF ls 00002 2 Telemetry Channels High Speed Interface 0 0 Thermistors Bi level Channels 0 0 Analog Channels 0 0 Timing Channels High Frequency Cl
162. testing and calibration activities in the roughly annual active checkouts The Alice passive checkout plan runs e reduced power up check AALS104A e Checksums AALS703A e Nine runs of the door performance test AALS404A e Power off AALS103A Active Checkouts These tests will be more extensive than the passive checkouts typically lasting a total of several weeks providing more time for each instrument They will allow for special pointing higher Science data production and more immediate data downlink and monitoring The Alice active checkout plans will differ each time but typically will likely include e Arun of the standard Passive Checkout operations 48 Rosetta ALICE User Manual e A full power up check AALS101A long decontamination running only the optics heaters it was decided adding detector HV to decontaminations is not necessary or desirable HV rampup AALS302x Many exposures different voltages to check pulse height distributions to determine best operating voltage e Three long each 1 hour or longer dark exposures AALS531A e Deep background sky exposures e Calibration observations of at least two stars including Alignment scans across the three parts upper wide narrow middle lower wide of the slit in pixel list mode o Jailbar flux calibrations in the three parts of the slit in histogram mode o Pixel list exposure to measure jitter of the star in the slit e Verificatio
163. the Alice Flight Operations Log 10 SAFETY MASK UPDATES SMU 1 Certification i The PM must authorize any update of the Safety Mask saved in the Alice context in writing ii Such authorization including the revised Safety Mask and the reason for each change shall be recorded in the Alice Flight Operations Log 11 EEPROM MEMORY PATCH EMP EMP 1 Certification i The PM must authorize any EEPROM memory patch in writing ii Such authorization including the reason for each memory patch shall be recorded in the Alice Flight Operations Log 2 Total Cycles i The total number of EEPROM memory patch cycles since launch should not exceed 10 000 per EEPROM page for a safety factor of 2 and should be rationed accordingly ii Load new EEPROM beginning on modulo 128 byte page boundaries and write all 128 bytes at one time can do this 10 000 times in each 128 byte page iii Maintain a single counter for each of the four 32 kbyte segments do not maintain a counter for each 128 byte page iv When uploading new code write to one of the four segments verify the load as accurate and then repeat for the other duplicate images EMP 3 Refresh Rate i Each EEPROM page should be refreshed or updated at least once every 5 years ii EEPROM contents will be monitored e g via checksums and or memory dumps annually to check for degradation and updated more frequently than once per 5 years if monitor results show it t
164. tics Requirements per Paragraph 2 4 9 EID A Converter switching frequency is 550 kHz One Waiver for out of spec performance in CONSERT 10 dB out at 90 MHz notch see Waiver RO ALI RW 009 Attachment 10 2 2 2 Pyrotechnic Interface Circuits Alice EID B 2 5 General Description The Alice instrument uses pyrotechnic devices called dimple actuators to initiate several functions It uses a pair of dimple actuators to release the mechanism that secures the detector vacuum cover a second pair primary and redundant to release the latch that holds the aperture door locked during launch and a third pair primary and redundant to release the fail safe aperture door if the primary aperture door should be rendered inoperable during the course of the mission Separate connections between the pyrotechnic connector and each dimple actuator primary and redundant are implemented six actuators are activated directly by the spacecraft upon ground command Table 2 3 lists the Alice pyrotechnic devices The initiator characteristics are given in the Alice EID B 2 5 Table 2 5 1 2 Table 2 3 Initiator Function and Supply applicable prime and redundant Interface Connector Aperture Door Uncage Dimple Actuator Spacecraft Pyrotechnic prime and redundant Interface Connector 15 Rosetta ALICE User Manual Function Initiator Principle Power supplied by if applicable Aperture failsafe door Dimple Actuator Spacecraft Pyro
165. tion dump Linear multiplier for base acquisition cycles volume in version 2 5 of the flight software a special value is defined 255 this indicates that the repeat continues till explicitly commanded to stop Histogram WinLowSpectral Selected Spectral and Spatial window determine selected part of acquired WinHighSpectral image Collapse factors allow for linear collapse in either dimension separately The window selected in dump specification lists both a spectral WinLowsSpatial range 0 1023 a spatial range 0 31 and collapse factors Both windowing WinHighSpatial and collapse result in reductions of amount of generated data Specified acquisition duration does not influence the generated data volume since each CollapseSpec acquisition produces one histogram CollapseSpat PixelList time limited WinLowSpectral Number of captured events depends on brightness of observed object and WinHighSpectral selected hackrate until memory is filled WinLowSpatial data volume time hack_rate photon_rate WinHighSpatial Post acquisition windowing will only select events that occurred within the Acquistion Duration Hackrate selected window but data volume reduction is unknown as distribution of captured event is a priori unknown PixelList count limited WinLowSpectral Total number of acquisition counts specifies directly the number of entries oct acquired duration of acquisition will vary depending on th
166. to control the instrument operation At any given time the software in the Alice instrument is operating in one of several states Alice makes transitions between states according to telecommands and the results of internal safety monitoring procedures The current operating state of Alice at any time defines what the instrument is doing what commands are allowed and the related data flow AFS implements the following states safe e safe dump e checkout e hold e acquire dump First a detailed description of these 6 states will be given and the mode transition diagram that describes the operations of the instrument In housekeeping telemetry the instrument will report one of these six states Following this a simplified mode diagram will be presented that shows the basic modes that determine the data generation Safe State The safe state is the default state for the software whenever Alice is first powered on or restarted It is also the state entered whenever something occurs on board to cause the instrument to safe itself In the safe state the high voltage power supply is shut down either idle or off and the aperture door is closed up on entry into the safe state configurable Command acceptance is limited so that the instrument cannot be activated while in the safe state except that acquisition commands are accepted Safe Dump State The safe dump state provides a means of dumping science data while the instrument is shut
167. tta ALICE User Manual safety condition bright object safety condition pressure trend boolean 1 safety condition pressure alert safety condition high voltage safety condition temperature boolean 1 safety override 1 Jboolean 1 HkSafetyMask bool 1 dust alert safety mask bits true condition masked bool 1 bright bool 1 pres trend bool 1 pres alert bool 1 HVPS bool 1 temp 2 spare etector electronics temperature ADC counts etector housing temperature amp DH electronics temperature HkInstrHousingTemp unsigned 8 instrument housing temperature HkTestStatus bool 1 rtx clock Self test results set to Oxff at start of Self Test command 192 23 0 bool 1 fine clock test completed succesfully value only valid after completion of the Self bool 1 RAM memory Test bool 1 acq page switch bool 1 acq memory 3 bool 1 acq memory 2 bool 1 acq memory 1 bool 1 acq memory 0 HkAfsVersion unsigned 4 software version major version unsigned 4 minor version Notes Packet production rate is determined by a parameter in the A ice software parameter file The default rate is one packet per 30 seconds The rate can be changed by private telecommand for exceptional situations troubleshooting Whenever this packet is generated all data fields are filled in with the most recent measured values or state information the only exception being the field HkTestStatus that is only u
168. ucture ID ata Data Field EID EvParmld sed EvParmTable EvParmValo its EvParmVal1 unsigned 8 bits table 1 parameter value EvParmVal2 unsigned 8 bits table 2 parameter value 82 Rosetta ALICE User Manual Telemetry Packet Definition Alice Packet Name Parameter read error event Alice Packet Function Indicate error reading internal parameter severity on board Generation Rules when none of three parameter readings agree Header Information Process ID Service Type Structure ID 0005 data Data Field Information Data Field Remarks EID value 40005 EvParmld parameter identifier EvParmValO table 0 parameter value 1 able 1 parameter value EvParmVal2 table 2 parameter value Telemetry Packet Definition Alice Header Information Service Type Service Subtype 3 4 notes Data Field Information Data Field EID 7 EvSafetyld enum 4 safety condition identifier 0 dust alert 1 bright object 2 pres trend 3 pres alert 4 HVPS error 5 over temp 6 15 not used EvSafetySubld sub identifier depends on value of EvSafetyID above for temperature safety this field contains the ADC channel of the temperature sensor causing the safety for HVPS safety this field identifies which HVPS check caused the error as follows 0 anode voltage limits 1 7 strip current limits 2 MCP tolerance error EvSafetyValue unsigned 16 bits safety condition value de
169. ull system level verification program prior to S C shipment to the launch site These tests must only be run with Alice team members present The HV safing plug must be installed to run these tests except during the EMI EMC test when the HVPS is commanded to 250 V Mission Simulation Test MST The MST is designed to test S C operations during the asteroid flyby encounter The test is mainly aimed at testing the S C operations but the experiments are used to generate a realistic data flow The Alice test sequences used during the Thermal Vacuum Thermal Balance tests will be re used these test sequences put Alice in different acquisition modes without activating the Alice detector HVPS Specific Performance Test SPT The Alice SPT shall verify the electrical and radiometric functionality of the Alice instrument with operation of the detector and HVPS concurrent with UV stimulation of the instrument via a portable GSE UV light source attached to the front of the Alice housing The SPT test will be conducted using the Alice End to End Radiometric Test S C version procedure 8225 ETE RAD SC 01 see Attachment 5 This test will be performed 1 during the BT at delivery to the S C contractor Alenia 2 during IST following payload integration 3 following the S C vibration test 4 upon completion of the full system level verification program prior to S C shipment to the launch site and 5 at the launch site To conduct this test
170. urfaces are over coated with sputtered SiC Control of internal stray light is achieved with a well baffled optical cavity and a holographic diffraction grating that has low scatter and near zero line ghost problems 35 Rosetta ALICE User Manual For contamination control heaters are mounted to the back surfaces of the OAP mirror and grating to prevent cold trapping of contaminants during flight To protect the sensitive photocathodes and MCP surfaces from exposure to moisture and other harmful contaminants during ground operations instrument integration and the early stages of the mission the detector tube body assembly is enclosed a vacuum chamber with a front door that was successfully and permanently opened during the early commissioning phases of the flight For additional protection of the optics and detector from particulate contamination during the flight a front entrance aperture door is included that can close when the dust or gas levels are too high for safe operation and exposure i e when the Rosetta Orbiter is close to the active comet nucleus or the light levels are too high The telescope baffle vanes also help to shield the OAP mirror from bombardment of small particles that enter the telescope entrance aperture 3 1 3 Entrance Slit Design The spectrograph entrance slit assembly design is shown in Figure 3 1 1 The slit is composed of three sections plus a pinhole mask The center section of the slit provides high
171. used for the safety checking the safety limit has to be increased in order to prevent triggering the instrument safing Note that this doubling does not occur in the count rate acquisition mode since the count rate acquisition is a completely software controlled acquisition mode that does not use the digital event interface 3 1 9 Code Memory Management The Alice instrument has different code memory spaces After power up Alice will start executing code from PROM memory The code is directly executed from PROM in the C amp DH architecture there are no drawbacks to executing from PROM and the big advantage is that the code cannot accidentally overwrite itself The C amp DH also provides four separate EEPROM pages from which the processor may execute code At launch these pages contained the same code images as the PROM so these were just redundant code images All EEPROM pages have been patched with new versions of the code since launch By telecommand Alice may be instructed to start executing code from one of the four EEPROM pages This redundant storage is initially used to provide an additional safeguard during the software startup the PROM code is verified using a checksum embedded in the PROM code If the checksum fails the code is assumed damaged and Alice starts testing the four EEPROM pages If on any of those pages code with a valid checksum stored again with the code then in the EEPROM memory is found that page will start execution
172. will be opened This activity will take place only after it has been determined from ROSINA pressure data that there is minimal outgassing from the surrounding spacecraft With Alice s low voltage power on and the detector HVPS OFF the command to open the front door will be executed This procedure will include firing the aperture door dimple motors to un cage the aperture door and powering the limited angle torque motor to open the door Once the door has been opened the instrument s internal surfaces will be allowed to outgas through the entrance aperture out into space for a period of time sufficient to fully out gas the Alice instrument This outgassing may be assisted by using the mirror and grating heaters to increase the temperature of these components Following this period the Alice detector door may be opened Detector Vacuum Door Opening During the initial turn on and checkout of Alice Commissioning Phase I see Attachment 7 the detector vacuum door will be opened for the first and only time during the flight With Alice s low voltage power on the instrument s front aperture door open and the detector HVPS OFF the command to open the vacuum cover will be executed Once the cover has been opened the detector s internal surfaces will be allowed to outgas into the surrounding spectrograph housing section and out into space through the entrance slit vent baffles and telescope entrance aperture for a period of time sufficient to equi
173. y be run with Alice team members present The HV safing plug must be removed to run this test Unit Functional Test UFT The Alice UFT shall verify the full electrical functionality of the A ice instrument excluding operation of the detector HVPS This test will be performed after integration of Alice onto the S C and will represent the baseline functionality test of Alice post S C integration The will consist of i the Alice Full Functional Test procedure 8225 FTP 01 see attachment 3 followed by ii the Alice Full Functional Test scripts as outlined in SwRI Technical Note Test Sequence Definitions for A ice Flight Software 8225 TEST DEF 01 see attachment 4 These tests must only be run with Alice team members present The HV safing plug must be installed to run these tests Integrated System Test IST The Alice IST shall verify the full electrical functionality of the Alice instrument excluding operation of the detector HVPS This test will be conducted using the Alice Full 59 Rosetta ALICE User Manual Functional Test scripts as outlined in SwRI Technical Note Test Sequence Definitions for Alice Flight Software 8225 TEST_DEF 01 see attachment 4 The IST will be performed 1 following payload integration 2 after major spacecraft transportation 3 during S C EMI EMC tests 4 following the S C vibration test 5 following the S C thermal balance thermal vacuum test and 6 upon completion of the f
174. y off the edge of the detector This pulser can be turned on and off by command and allows testing of the entire Alice detector and C amp DH electronic signal path without having to power on the detector high voltage power supply In addition the position of the stim pixels provides a wavelength fiducial that can shift with 275 Rosetta ALICE User Manual operating temperature 0 5 pixel degC towards shorter wavelengths in flight the right most stim on the short wavelength side of the detector is typically shifted off the array due to the thermal environment of the detector electronics 3 1 5 Electrical Design The instrument support electronics see Figure 3 1 3 on Alice include the power controller electronics PCE the C amp DH electronics the telemetry command interface electronics the decontamination heater system and the detector high voltage power supply HVPS All of these systems are controlled by a rad hardened SA 3865 microprocessor supplied by Sandia Associates with 32 KB of local program RAM and 64 KB of acquisition RAM along with 32 KB of program ROM and 128 KB of EEPROM of the instrument support electronics are contained on 5 boards mounted just behind the detector electronics see Figure 1 3 1 and Figure 1 3 3 ANODE MCP VOLTAGE 3 STRIP CURRENT OTHER ANALOGS HK STATUS MPX ADC THERMISTOR FROM DETECTOR THERMISTOR FROM OPTICS ACQUISITION MEMORY 32K x 16 CLOCK SYNC
175. y the S C then the S C will send a telecommand TC to A ice to enter the SAFE state followed shortly thereafter with a command to power Alice off Commanding A ice to the SAFE state will switch off the HVPS and if enabled close the aperture door 63 Rosetta ALICE User Manual If Alice is running a MAD acquisition with multiple acquisitions in sequence commanded the change to safe state will only terminate the current active acquisition and switch to safe state It will not however terminate the actual MAD acquisition sequencing When the next scheduled acquisition start moment arrives the nominal acquisition start sequence is executed including HV on door open etc Hence if a long MAD sequence of acquisitions was stopped somewhere in the middle because of a temporary safety condition the MAD would continue and after expiring the safety time out which would initially be set to a large value further acquisitions would be taken For example if acquisitions were commanded to start every 10 minutes past the hour this time schedule would be upheld and a start acquisition would only be attempted at 10 minutes past the hour for as long as the overall MAD was in effect Table 5 2 List of Spacecraft Monitored Alice Housekeeping Parameters DMS MONITORING Instrument Alice Monitored Entit Monitoring Requirements Action on Error Alice LCL current um Alice off Operating state limits urn Alice off Count rate limits ur Alice off MCP V

Alice - PDS Small Bodies Node

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