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33Draft ECSS-M-00-03A

1. A T 3 5 4 1 4 c A T 3 5 6 4 1 4 d PDR CDR RoD A 3 4 2 1 a PDR A 3 4 2 1 PDR gt RoD 3 4 2 1 6 11113 4 2 1 4 PDR RoD A 3 25 DRAFT ECSS E 20B rev 1 17 April 2008 4 2 1 e PDR RoD A 3 4 2 1 f PDR RoD 3 4 2 1 9 1 3115 4 2 1 5 2 PDR RoD T 3 5 4 2 1 h PDR RoD A 3 4 2 1 1 PDR RoD A 3 4 2 1 PDR RoD 3 4 2 1 PDR gt RoD A T 3115 4 2 1 1 PDR RoD A T 3 5 4 9 1 m PDR RoD 3 4 2 1 n PDR RoD 3 4 2 1 0 3 5 4 2 1 p PDR 3115 4 2 1 9 PDR A 3 4211 gt 3115 4 2 1 5 PDR RoD A 3 4 2 1 t PDR CDR RoD A 3 4 2 1 3 422724 SRR RoD 2116 4 2 2 2 PDR RoD A 2113 4 2 2 2 PDR RoD A 2113 42224 PDR RoD A 2113 4 2 2 2 6 PDR RoD A 2 3 4 2 3 INS 1113 4 2 3 FAR INS 3 4 2 3 c FAR RoD 3 4 2 3 d CDR gt RoD A 3 4 2 3 CDR RoD INS 11113 4 2 3 8 CDR RoD INS 1 3 4 2 3 PDR gt RoD 1 4 2 3 6 PDR RoD 1 4 2 3 1 PDR RoD 1 4 2 3 PDR RoD 1 4 2 3 k PDR RoD A 3 4 2 3 1 PDR RoD INS 3
2. 1 be defined and 2 result in the specification of the input impedance seen by the power conditioning units b The power interfaces with the power subsystem e g umbilical and EGSE shall be specified The availability of the specified solar array power up to the power conditioning shall be verified by a representative end to end test at spacecraft level and correlated analysis d The solar array interface voltage shall be defined at the solar array harness connector interface e The solar array interface voltage shall include voltage losses within the electrical circuitry of the solar array including at least blocking diodes wiring resistance and losses associated with harness interconnections in operational conditions 5 5 Energy generation 5 5 1 Solarcell coverglass SCA and PVA requirements For the qualification of solar cells protection diodes coverglass SCA and PVA see ECSS E 20 08B 5 5 2 Solaramay specification and design a The solar array shall be designed to meet the average power demand in each mission phase including battery recharge power during operational life with the string loss tolerance defined by the customer NOTE The solar array is designed to be single failure tolerant at string level NOTE In order to meet the solar array reliability requirements the impact of other loss factors may lead to the addition of other spare strings b In case of a sunlight regulated bus provi
3. 57 57 57 58 58 59 59 59 60 60 61 61 61 62 62 63 63 63 63 64 65 65 66 71 71 DRAFT ECSS E 20B rev 1 17 April 2008 5 7 3 RF Power 7 3 1 Overview 7 3 2 RF Power handling thermal 7 3 3 Corona or Gas Discharge 7 3 4 Qualification for power handling and gas discharge 7 4 Passive intermodulation 7 4 1 Overview 7 4 2 General requirements 7 4 3 Identification of potentially critical intermodulation products 7 4 4 Verification 7 4 5 Qualification for passive intermodulation 7 5 Verification 1 identification A 2 Expected response 1 DRD identification B 2 Expected response C 1 DRD identification C 2 Expected response Bibliography Tables Table 4 1 General verification requirements 25 Table 5 1 Parameters for BOL worst and best case 33 Table 5 2 Additional power parameters for EOL worst and best case calculations 34 Table 5 3 General verification requirements nnns 52 Table 7 1 Antennas verification requirements sesenta 72 Table 7 2 Power handling and Passive intermodulation table of verification 77 DRAFT ECSS E 20B rev 1 17 April 2008 55 1 Scope This Standard establishes the basic rules and general principles applicable to the electric
4. NOTE The rationale for this requirement 15 the following It is in practice difficult to design output impedance below 10 milliohm without an unwanted effect of the intrinsic connections and components resistance For the design of a bus with 10 milliohm output impedance such that a 50 load modulation induces 1 voltage change maximum as per 5 7 2 1 1 requirement 0 5 P U x 0 01 lt 0 01U which means lt U7 0 5 Thus for U 28 lt 1 57 kW 50 lt 5 100 V P 20 kW In practice at 50 V example higher power has been used on telecom satellite buses because the 1 voltage change referred to a lower load change of 20 to 30 instead of 50 96 h A fully regulated bus shall keep its nominal value in steady state within 0 5 of the bus voltage at the main regulation point 1 With a fully regulated bus in nominal operation 1 For load transients of up to 50 of the nominal load bus voltage transients shall not exceed 196 of its nominal value 2 For any source and load transients the bus voltage shall remain within 596 of its nominal value Fuses should be avoided to maintain the quality of the bus NOTE The rationale for requirement h to j is the following In order to be advantageous over an unregulated scheme a regulated bus ensures a good regulation quality at the regulation point including when the various loads on the bus are changing The regulated bus is designed to ensure that n
5. There shall be umbilical and test connectors to provide external electrical interfaces e g with the launcher and with the EGSE NOTE Functions provided include all those necessary for supporting AIT and launch site activities e g monitor spacecraft operation maintain synchronization between satellite EGSE and real time simulators put the satellite in a defined operation scenario like a quick upload of SW 1 Electrical and Safe and arm plugs shall be provided for disabling on ground hazard functions NOTE For harness design and manufacturing see the document RNC CNES Q 70 511 as guideline and handbook Cross strapping of redundant paths and circuits shall not be carried out in the harness 59 Safety The design of electrical systems and payloads shall include safety aspects as documented in IEC 60479 1994 Effects of current on human beings and livestock 5 10 High voltage engineering a For non pressurised and non potted high voltage equipment the applicable pressure range when this equipment is on shall be specified b Non pressurised and non potted high voltage equipment shall be designed and manufactured to avoid discharge phenomena according to Pashen curves valid for its specified pressure range c The field enhancement factors shall be ensured by the design NOTE This applies in particular to the routing of high voltage cables d For potted circuits the glass transition point of the potting material
6. lt 1 gt Introduction The EMEVP shall contain a description of the purpose objective content and the reason of prompting its preparation lt 2 gt Applicable and reference documents The EMEVP shall list the applicable and reference documents to support the generation of the document 81 DRAFT ECSS E 20B rev 1 17 April 2008 5 3 The 4 The a d Terms and definitions abbreviated terms and symbols EMEVP shall include any additional definition abbreviation or symbol used Elements of the plan EMEVP shall list the requirements of the plan including methods to be used to select critical circuits used to monitor conformance to degradation criteria and safety margins including the definition of the method of selection procedures used for developing failure criteria and limits test conditions and procedures for all electronic and electrical equipment installed in or associated with spacecraft and sequence for operations during tests including switching specific tolerance for particular measurement An intra system compatibility culprit victim test matrix shall be included in the EMEVP showing all combinations of individual equipment subsystems to be tested in order to verify overall intra system compatibility The description of the Step by step test procedures for operation of all matrix equipment shall be included in the EMEVP to support test execution e impleme
7. operation the main power bus voltage shall remain below its maximum specified overvoltage requirement r The design shall ensure that a short circuit to ground or to the return line of a solar array section does not result in a failure of category 1 and 2 criticality NOTE The definition of criticalities can be found in Table 1 of ECSS Q 40C 5 7 3 Battery Charge and Discharge Management a Battery chargers shall be designed to ensure charging of a battery discharged down to zero volts NOTE The possibility of recovery applies mainly to the capability of recharging the battery exposed to extreme discharge conditions eg lithium ion technology b The solar array power shall be capable to satisfy the recharge of the battery in any mission phase with the essential loads connected on the bus and one worst case load connected representing a failure whichever is the more constraining NOTE This is to ensure recovery from loss of spacecraft attitude The minimum energy reserve in the battery shall be enough to guarantee the mission and a safe recovery of the spacecraft under all conditions NOTE Take into account that the charge rate plays a major role in the effectiveness of battery recharge 43 DRAFT ECSS E 20B rev 1 17 April 2008 055 The charging technique shall be designed to ensure that the batteries never overcharged NOTE To avoid over or under charge when taper charging is employed th
8. 5 6 2 Batteries 5 6 3 Battery cell 5 6 4 Battery use and storage 5 6 5 Battery safety 5 7 Powerconditioning and control Applicability Spacecraft bus Battery Charge and Discharge Management Bus under voltage or over voltage Power converters and regulators Payload interaction 5 8 protection 5 8 1 General 5 8 2 Harness 5 9 Safety 5 10 High voltage engineering 5 11 Verification 5 11 1 Provisions 5 11 2 Documentation 6 Hectomagnetic compatibility 6 1 Overview 6 2 Policy 6 2 1 Overall EMC programme 6 2 2 EMC control plan 6 2 3 Electromagnetic compatibility advisory board EMCAB 6 3 System level 1 Electromagnetic interference safety margin EMISM 2 Inter system and with environment 3 Hazards of electromagnetic radiation 4 Spacecraft charging protection program 5 Intrasystem 6 Radio Frequency Compatibility 7 Spacecraft DC magnetic field emission 8 Design provisions for EMC control 9 Detailed design requirements 6 4 Verification 6 4 1 Verification plan and report 6 4 2 Safety margin demonstration for critical or EED circuit 6 4 3 Detailed verification requirements w CJ CJ CJ WW CJ CJ 7 Radio frequency systems 7 1 Functional description 7 2 Antennas 7 2 1 General 7 2 2 Antenna structure 7 2 3 Antenna interfaces 7 2 4 Antennas Verification
9. Radio frequency RF systems include transmitters receivers antennas and their associated transmission lines waveguides including connectors operating typically in the range from 30 MHz to 300 GHz The transmitted or received signals can be narrowband or wideband often with complex modulation and sometimes with multiple carriers Transmitters and receivers require high mutual insulation and antennas can interact strongly with the spacecraft For achieving the RF performance requirements the following parameters are considered by the engineering process antenna field of view and polarization link or radiometric budget spatial and spectral resolution signal to noise ratio frequency plan For achieving the performances requirement the following parameters are considered by the RF design and development transmitter power receiver sensitivity active and passive intermodulation products multipaction corona spectral purity VSWR frequency stability reflection and diffraction effects on antenna performance mutual coupling between antennas insulation between transmitter and receiver EIRP 64 DRAFT ECSS E 20B rev 1 17 April 2008 7 2 Antennas 7 2 1 General 7 2 1 1 Overview In conformity with ECSS E 10 Part 1B 4 3 8 4 6 1 3 and 5 4 budgets and margins are established and requested during Project phase B and reviewed in all subsequent phases of
10. within a different package e g Hybrid and Integrated Circuit to avoid failure propagation For redundant functions implemented on the same PCB 1 a physical separation e g by a minimum distance insulation or cut out shall be provided with no risk of thermal or other failure propagation 2 any deviation of the physical separation specified in 1 shall be tracked in the Critical item List For hybrids redundant and protection functions shall be located in a different cavity l In case a cold redundant function is simultaneously activated together with the nominal one by a deliberate or wrong command or due to a fault this shall not induce permanent degradation of either of the two functions e g thermal EMC or loss of the mission before FDIR action 2 In case verification by analysis is not conclusive a complementary verification by test shall be performed Any active equipment dissipating more than 20 W in nominal or failure condition shall include a temperature monitoring capability individual heaters excluded In case of signal cross strapping no single failure of either interface circuit shall propagate to the other one In the case of hot redundant essential functions either latching protection shall not be used or it shall have an autonomous periodic reset DRAFT ECSS E 20B rev 1 17 April 2008 5 Override of critical on board autonomous functions shall be implemented only if a safety
11. 4 2 3 m PDR RoD A 3 4 2 3 n PDR RoD 1 26 DRAFT ECSS E 20B rev 1 17 April 2008 4 2 4 gt INS 113117 4 2 4 11113117 4 2 4 PDR RoD 3117 4 2 4 14 2 PDR RoD A 3 4 6 4 2 4 6 CDR gt A T 3115 4 2 4 f PDR RoD A or T 3115 4 24 g CDR A T 3115 4 2 4 PDR RoD A 3 4 2 4 1 PDR RoD T 3115 4 2 4 PDR gt RoD T 3 5 4 2 4 k PDR FAR RoD T 31 5 4 2 4 1 3115 4 2 5 1 PDR RoD INS 3 4 2 6 a CDR RoD 3 4 9 6 b CDR RoD 3 4 2 6 c PDR INS 3 4 2 6 d PDR INS 3 4 4 2 SRR RoD 3 4 4 2 c PDR A 3 27 DRAFT ECSS E 20B rev 1 17 April 2008 55 5 Electrical power 5 1 Functional description Electrical power is used by all active spacecraft systems and equipment for their operation Electrical power engineering includes power generation energy storage conditioning line protection and distribution as well as high voltage engineering 5 2 Powerand budgets 5 2 1 Overview Budgets and margins shall be established during Project phase B and reviewed in all subsequent phases of the project 5 2 2 Provisions 5 2 2 1 Power subsystem The power subsystem of a spacecraft shall be able to generate store condition distribute and
12. 5 3 INS 6 5 5 3 3151 5 5 3 21 3 5 5 3 4 CDR T 5 5 5 3 3 5 5 3 4 RoD A 2 3 5 5 3 2 RoD A 21 3 5 5 3 h 2 3 5 5 3 1 2 3 5 5 3 2 3 5 5 3 5 21 3 5 5 4 RoD A 3 5 5 4 b RoD 3 5 5 4 6 RoD A 3 5 6 2 RoD A 1 2 3 6 5 6 2 b RoD A T 3 5 5 6 2 c 1 RoD A 3 6 5 6 2 c 2 T 5 5 6 2 4 RoD A 3 5 6 2 1 2 amp 3 RoD A 1112113 5 6 2 4 RoD A 3 5 6 2 8 PDR gt RoD INS 3 6 5 6 2 h PDR gt RoD A 3 5 6 9 1 RoD T 3151 5 6 2 1113 5 6 2 5 CDR gt INS 7 5 6 2 1 PDR gt RoD A T 3 5 5 6 2 m A T 3 5 5 6 3 RoD A 3 7 5 6 3 b PDR gt RoD A T 3 5 6 3 PDR gt RoD A 3 5 6 3 d 1 PDR gt A 3 5 6 3 d 2 PDR gt T 5 53 DRAFT ECSS E 20B rev 1 17 April 2008 5 6 3 6 PDR gt RoD A 3 7 5 6 3 PDR gt RoD INS 3 5 6 4 PDR gt RoD A 3 5 6 4 b PDR gt RoD 7 5 6 4 c TRR RoD 18116 5 6 4 4 RoD 5 5 6 4 6 PDR gt RoD A T 3 5 5 6 4 4 CDR R
13. ECSS E 20B 1 CSS 17 April 2008 Variations with frequency angle where applicable and aging of all above parameters 7 2 3 Antenna interfaces 7 2 3 1 Guided wave interfaces a Connectors or waveguide flanges at the antenna ports shall be demonstrated to have the specified power handling capabilities and impedance mismatch factors NOTE Antenna RF ports are realised using a wave guiding structure coaxial cable or waveguide in most instances Connectors or flanges are used to realise the physical interface b It shall be demonstrated that the generation of passive inter modulation products that can occur at the antenna ports is below the specified limits agreed with the customer For antenna ports 1 The applicable pressure range and gas properties shall be specified 2 The design and manufacturing shall be performed to avoid discharge phenomena according to Pashen curves valid for its specified pressure range and gas properties NOTE See section 7 3 and 7 4 for further details 7 2 3 2 Radiative interfaces a Electromagnetic interactions among the antenna and the surrounding spacecraft structure and appendages shall be quantified starting from Phase B as a minimum and their impact on antenna performances assessed NOTE The field radiated or received by the antenna interacts with the surrounding environment Interactions with the spacecraft structure and appendages usually have a direct impa
14. RoD 6 5 10 b 3 5 10 3 5 10 4 3 5 10 3 5 11 2 SRR RoD 3 5 11 2 c 3 56 DRAFT ECSS E 20B rev 1 17 April 2008 6 Electromagnetic compatibility EMC 6 1 6 2 Overview Policy The objective of the following EMC requirements is to ensure that the space system is designed to achieve electromagnetic compatibility between all equipment and subsystems within the space system and in the presence of its self induced and external electromagnetic environment 6 2 1 Overall programme The supplier shall establish an overall EMC Programme NOTE NOTE The EMC programme is an activity the purpose of which is to provide for spacecraft level compatibility with the minimum impact to programme cost schedule and operational capabilities The role of the customer in the EMC programme is that of top level oversight The EMC Programme 15 based on requirements of this standard the statement of work spacecraft specification and other applicable contractual documents The EMC Programme shall 1 Plan and verify that EMC technical criteria mainly design and management controls are in place to achieve EMC 2 Plan and accomplish the verification of spacecraft level 57 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss 6 2 EMC control plan a As
15. The test frequencies number of carriers and power levels of these carriers shall be those as identified in 7 4 3 b Qualification testing shall be carried out l on RF non radiative passive components or equipments or systems over the full qualification temperature range 2 on RF radiative components equipments or systems over a temperature range to be agreed with the customer range which can be limited to ambient temperature Acceptance testing shall be carried out on flight components equipments or systems over an acceptance temperature range to be agreed with the customer range which can be limited to ambient temperature l 7 4 5 Qualification for passive intermodulation The amplitude of each passive intermodulation product falling within any of the satellite receive bands or third party protected frequency bands shall be lower than the level specified in 7 4 2 a 7 5 Verification The requirements of the Clauses 7 3 and 7 4 shall be verified by the verification methods at the reviews and recorded in the documentation as specified in Table 7 2 76 DRAFT ECSS E 20B rev 1 17 April 2008 ERS Table 7 2 Power handling and Passive intermodulation table of verification Requirement Treated at the following Treated by the Recorded in verification p
16. bleeding resistors are used to control both electrostatic charging and power loss from the solar array section and dissipation in the resistor Itself in case of a cell string to panel short including de rating g At solar array level one short between a solar cell string and a conductive panel structure shall not produce any solar array power loss h At solar array level in case of two shorts on the same panel the power loss shall not be more than the power of two strings 1 The layout shall be designed to meet the solar array magnetic moment requirements Js 1 The solar array shall be designed to survive the atomic oxygen orbit environment without performance degradation below specification 2 In case verification by analysis is not conclusive a complementary verification by test shall be performed Provision shall be made to prevent failure due to power transients from the power sub system or due to operation in shadow e g Individual string blocking diodes Solar array shall be subdivided in sections m Solar cells shall be protected against any deleterious reverse bias conditions 31 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 5 3 Solaramay power computation a The solar spectrum for near earth and lunar missions shall be as per annex A of ECSS E 20 08A b The model used for the computation of the IV curve of the solar cell shall be validated by test on the specific solar cell type
17. customer 6 3 4 2 General The spacecraft charging protection programme shall include the preparation and maintenance of an analysis plan and the preparation and maintenance of a test plan NOTE The objective of the programme is to ensure that the space vehicle is capable of operating in the specified space plasma charging environment and its energetic electron content without degradation of the specified space vehicle capability and reliability without changes in operational modes location or orientation d The performance shall be accomplished without the intervention of external 60 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss control such as commands from a ground station 6 The spacecraft charging protection programme shall include 1 surface electrostatic charging 2 threat from internal electrostatic charging of dielectric materials and isolated conducting items due to the penetration of energetic electrons as defined in the environmental specification NOTE ECSS E 20 06 is intended to provide clear and consistent requirements to the application of measures to assess and mitigate hazardous effects arising from spacecraft charging and other environmental effects on a spacecraft s electrical behaviour 6 3 4 3 Performance f The space vehicle electrical subsystem and system may undergo an outage during an arc discharge if operation and performance returns to specified levels within 1 a telemet
18. description of any deviations from step by step procedures in EMEVP test set up diagrams photographs as appropriate list of test equipment including calibration information recorded data or logs including instrument readings correction factors and reduced results methods of data reduction If value of data has been compromised due to test conditions the reason and impact on results description of ambient and other test conditions 85 DRAFT ECSS E 20B rev 1 17 April 2008 Bibliography ECSS E 00A ECSS E 10 Part 1B ECSS E 10 02A ECSS E 10 03A ECSS E 20 01A ECSS E 20 06A ECSS E 30 Part 6A ECSS E 30 Part 7A ECSS E 30 Part 8A ECSS E 50 14A ECSS M 40B ECSS Q 20B ECSS Q 30B ECSS Q 40B ECSS Q 60 ECSS Q 70 10A ECSS Q 70 11A ECSS Q 70 22A ECSS Q 70 28A Space engineering Policy and principles Space engineering System engineering Part 1 Requirements and process Space engineering Verification Testing Multipaction Spacecraft charging Space engineering Mechanical Part 6 Pyrotechnics Space engineering Mechanical Part 7 Mechanical parts Space engineering Mechanical Part 8 Materials Space engineering Discrete interfaces Space project management Configuration management Space product assurance Quality assurance Space product assurance Dependability Space product assurance Safety Space product assurance Electrical electronic and electromech
19. for the mission solar cells characteristics shall be computed in and EOL conditions at maximum and minimum operating temperatures according to the mission profile d The EOL solar cell IV curve shall be measured at the temperatures specified in 5 5 3 c after irradiation with particles electrons and protons according to ECSS E20 08A chapter 7 5 12 and agreed with the customer e The forward voltage of the string blocking diode if present shall be computed 1 using the worst case voltage drop specified by the diode manufacturer 2 at the diode operating temperature corresponding to the operational string current for each mission phase in worst case conditions 32 DRAFT ECSS E 20B rev 1 17 April 2008 f The BOL worst and best case power calculations shall include the parameters indicated in Table 5 1 Table 5 1 Parameters for BOL worst and best case power calculations Type of Parameter Applicable to string loss gain Current Cell Current Random mismatch Calibration error Current Random Cover glass gain Current Direct loss Blocking Diode Voltage Direct Loss Harness Voltage Voltage Direct Drop Pointing error due to disorientation Current Direct and internal Solar Array error Orbital Losses amp Current amp Voltage Direct Sun Intensity Shadow losses 4 Current amp Voltage Direct Temperature Current amp Voltage Direct coef
20. implementation from the phase B design phase onwards f The battery supplier shall inform the customer of any change in design materials or process from cells which have experienced life testing or flight 37 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 6 4 Battery use and storage a The design of the spacecraft shall be such that cells and batteries can be removed and replaced at any time prior to launch without affecting the acceptance status of the rest of the spacecraft b For the procurement of cells and batteries the manufacturer shall supply a user manual including l maximum ground storage life where applicable before and after activation 2 maximum period of non use without special wake up cycling 3 range of battery temperatures and maximum durations during pre launch and operational phases 4 battery maintenance procedures during integration and pre launch phases including case of launch delay 5 storage procedure range of storage temperature cell discharge requirements before storage 6 humidity and packaging constraints for storage T maximum and minimum state of charge to be maintained during storage requirements on individual shorting of cells details of any trickle charge or periodic maintenance e g minimum voltage checks and top up charge to a maximum voltage in case a minimum cell voltage 1s reached 8 reactivation procedure after storage 9 Handling and cell connecting
21. in case of SEU an inhibition by pass e g stepper motor control loop by passed by a direct step by step command as back up Any on board autonomous protection override leading to hazardous situation for the mission category 1 and 2 criticality shall not be implemented NOTE E g an LCL function for instance protecting the main power Bus against a short circuit at Bus user level or Main Bus over voltage protection t SEE shall not activate protection circuits of essential functions NOTE mitigation techniques can be implemented to avoid such phenomena filtering majority voting etc The satellite electrical system shall be single point failure free or double point failure free for manned mission regardless of any occurrence of non destructive SEEs NOTE non destructive SEE is not a failure 20 DRAFT ECSS E 20B rev 1 17 April 2008 4 2 2 Data processing 4 2 2 1 Overview operational and mission specific data are processed for acquisition algorithm application transmission storage On board time is managed by data handling subsystem in line with the mission requirements Data processing includes the man machine interface if any The data processing system includes all hardware and software elements used for that purpose e g microprocessor and its instruction set interface means data busses and remote terminals 4 2 2 2 Provisions a Margins shall be defined at proje
22. interlock 15 implemented which prevents the activation of the override feature on both main and redundant functions Any protection latch which does not have autonomous reset capability shall be at least re settable from ground command m Any protection of an essential function shall not share with the essential function itself the same hybrid cavity or component or integrated circuit nor utilize common references or auxiliary supply n Essential functions shall not rely on other functions e g synchronization and auxiliary supply which are centrally generated NOTE That implies the capability of any equipment performing an essential function of operating independently of any external synchronization and auxiliary power supply 0 For essential functions supplied by lock up phenomenon requiring recovery via the removal of external power shall be prevented p units to be powered during launch shall be designed for operation with critical pressure q A venting analysis shall be performed for all units not designed to operate under partial pressure and not powered during launch to determine when they can safely be turned on r Any on board autonomous function the failure of which can result in malfunctions of category 1 and 2 criticality shall have override capability NOTE Examples of override are a simple inhibition or isolation e g cold or hot redundant chain s exists an H W reset e g
23. manufacturing errors thermo elastic effects and modification of the material characteristic in the orbit environment moisture release in composites 7 2 2 3 3 RF Lenses a Reflective and transmissive properties losses depolarisation and diffusivity of the materials and or composites used for the lenses shall be quantified and their impact on antenna performances assessed b Deviations from the nominal geometry of the lens shall be quantified and their impact on antenna performances assessed NOTE Typical deviations are due to manufacturing errors thermo elastic effects and modification of the material characteristic in the orbit environment moisture release in composites Measures to drain accumulated electric charges from all non conductive parts shall be implemented to avoid Electrostatic Discharge ESD d Any metallic parts shall be connected to the equipment DC ground to avoid Electrostatic Discharge ESD 7 2 2 3 4 RF Beam Forming Network a The circuit characteristics of the RF BFN shall be independently quantified and their impact on antenna performances assessed at least up to CDR b Deviations from the nominal geometry of the RF BFN shall be quantified and their impact on antenna performances assessed NOTE Typical deviations are due to manufacturing errors 68 DRAFT ECSS E 20B rev 1 17 April 2008 055 thermo elastic effects and modification of the material characteristic in the orbit enviro
24. manufacturing review board printed circuit board preliminary design review passive inter modulation product photovoltaic assembly qualification test report radio frequency review of design solar array drive solar cells assembly single event effects single event upsets system requirement review test test review board test readiness review telemetry telecommand ultraviolet verification control document DRAFT ECSS E 20B rev 1 17 April 2008 4 General requirements 41 Interface requirements 4 1 1 4 1 2 Overview ECSS E 10 Part 1B specifies that interfaces external or internal to a system are adequately specified 4 4 to 4 6 and verified 4 7 The following requirements address this issue and are processed in phase B C and D of a project as requested in 5 of ECSS E10Part1B Signals interfaces Interface engineering shall ensure that the characteristics on both sides of each interface are compatible including source and load impedances the effects of the interconnecting harness and the grounding network between both sides comprising common mode impedance conducted and radiated susceptibility and emission In order to minimize the number of interface types standard interface circuitry shall be defined to be applied throughout a project Except for direct commands to relay coils circuits receiving high level telecomm ands for direct execution of a major reconfiguration function or other critic
25. monitor the electrical power used by the spacecraft throughout all mission phases in the presence of all environments actually encountered 5 2 2 2 Engineering process The following process shall be followed a Perform an analysis of power demand versus power available including peak power in the platform and the payloads for all phases of the mission b Perform an analysis of the energy demand versus energy available in all phases of the missions including inrush power demands eclipses solar aspect angle and depointing 28 DRAFT ECSS E 20B rev 1 17 April 2008 5 Establish a power budget based the peak power values and an energy budget based on the average power values for all mission phases d Establish a plan for the maintenance and periodical review of the budget established in requirement c above during all project phases NOTE These budgets take into account spacecraft sun distance sun and eclipse durations solar aspect angle pointing accuracy environmental temperature and degradation effects reliability and safety aspects any one failure in the system two failures for manned mission not counting solar array string and battery cell failure Failure Detection Isolation and Recovery scenarios e A system margin of not less than 5 at FAR on available power and energy shall be included in the budgets available as a minimum with the solar array string losses as de
26. of category 1 and 2 at least two physically independent electrical barriers including associated control circuits are mandatory for arming and executing the command NOTE For criticality categories see ECSS Q 40C Tablel NOTE Mechanical barriers can be considered NOTE Physically independent electrical barriers and associated control circuits are the ones not sharing any hardware function and without risk of reciprocal failure propagation h Processor and simple logic circuits shall not be able to issue category 1 and 2 critical commands without a ground commanded arm safe or enable disable command NOTE To avoid inadvertent activation of processes enabled disabled by category 1 or 2 critical commands during ground operations and in low earth orbit phases it is necessary to foresee safety barriers arm safe commands to inhibit the execution of such critical commands Such safety barriers might be spacecraft skin connections to be established or broken just before flight or connections disconnection plugs to be activated by launcher stages release in flight The activation deactivation of such barriers has to be independent from on board processor 1 Any on board processing which issues commands to reconfigure subsystems or payloads shall be overridable and potentially inhibited by ground command NOTE For criticality categories see ECSS Q 40C Tablel No commands shall be issued unless the transmitter power supply volta
27. present also a Beam Forming Network can be present to distribute the RF signal 7 2 2 3 4 The effects of antenna support structures shall be quantified and the impact on antenna performances assessed 7 2 2 2 1 a NOTE b 7 2 2 2 2 a NOTE b Deformations of reflector antennas which parts are physically attached to different portions of the satellite platform shall be quantified and their impact on antenna performance assessed NOTE For large reflector antennas that use hold down and release deployment mechanisms as well as pointing devices ECSS E 33 Part 11A can be applied 66 DRAFT ECSS E 20B rev 1 17 April 2008 5 7 2 2 23 Amay antennas a The effect of the radiation of individual array element on the others shall be quantified and the impact on antenna performances assessed NOTE Array antennas are constituted by a number of radiating elements 7 2 2 3 1 possibly including an antenna RF chain Error Reference source not found and arranged in a more or less regular layout The RF signals are routed to from each element through a wave guiding network generally known as Beam Forming Network 7 2 2 3 4 An antenna support structure can also be present 7 2 2 3 6 b The effects of antenna support structures on the main RF wave propagation path shall be quantified and the impact on performance assessed Deformations of array antennas which parts are physically attached to differe
28. procedures and precautions 10 Cell and battery safety related information 11 Transportation requirements Flight batteries should not be used for ground operations to prevent any possible damage and subsequent degradation of life performance d If c above is not met the flight worthiness of the batteries shall be re verified e g by capacity measurements after these ground operations are completed in time for a possible replacement e Any test equipment interfacing with the battery shall include an associated undervoltage overvoltage overcurrent and over temperature activated insulation switch f Any cell which has experienced an electrical mechanical or thermal level outside the qualification range shall be flagged and tracked g Any cell which has experienced an electrical mechanical or thermal level outside the qualification range should be forbidden for flight 38 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 6 5 Battery safety 5 6 5 1 Overview Almost all battery technologies used aboard spacecraft can be hazardous if not properly managed Most are capable of delivering very high currents when shorted When abused cells can develop excessive internal pressure and eventually vent their contents in extreme cases explosively The electrolyte cell reactants and or reaction products expelled can be corrosive e g alkaline cells lithium SOs Lithium SOCl flammable e g lithium cell organic
29. rev 1 17 April 2008 5 NOTE They include among others the design placement of components shielding and employment of rejection filters 3 1 15 electromagnetic interference EMI undesired electrical phenomenon that is created by or adversely affects any device whose normal functioning is predicated upon the utilization of electrical phenomena NOTE It is characterized by the manifestation of degradation of the performance of an equipment transmission channel or system caused by an electromagnetic disturbance 3 1 16 electromagnetic interference safety margin EMISM ratio between the susceptibility threshold and the interference present on a critical test point 3 1 17 emission electromagnetic energy propagated by radiation or conduction 3 1 18 essential function function without which the operator cannot recover the spacecraft following any conceivable on board or ground based failure the spacecraft cannot be commanded the spacecraft permanently loses attitude and orbit control the spacecraft consumables e g fuel and energy are depleted to such an extent that more than 1096 of its lifetime is affected or the safety of the crew is threatened 3 1 19 foldback current limiter FCL non latching current limiting function where the current limit will decrease with the output voltage NOTE This function is used for power distribution and protection typically for essential loads 3 1 20 full
30. shall be outside the temperature range of qualification e The design of high voltage equipment shall be such that worst case DC and AC field strengths are less than half of the values for which breakdown can occur 50 DRAFT ECSS E 20B rev 1 17 April 2008 5 11 Verification 5 11 1 Provisions The requirements of this Clause 5 shall be verified by the verification methods at the reviews and recorded in the documentation as specified in Table 5 3 NOTE For verification see also ECSS E 10 02 5 11 2 Documentation a The DDJF contains all descriptions and analyses meant to verify that the design meets the requirements It shall cover in particular Design report PSA WCA FMECA thermal Analysis Radiation Analysis analysis supported by the detailed circuit diagrams b Failure modes of all components used in a unit shall be defined FMECA shall be performed and based the failure modes previously defined at component level 51 DRAFT ECSS E 20B rev 1 17 April 2008 Table 5 3 General verification requirements Requirement Treated at the Treated by the Recorded in following following verification points verification methods SRR RoD 1 Electrical ICD including SAR ICD and PDR T Battery ICD CDR A 2 Budget documents TRR INS Power Energy Processor memory TRB budgets etc DRB NOTES DDJ F FAR RoD includes review of 4 GDIR X Preliminary f
31. the project 72 2 Provisions 7 2 1 2 1 Definition of terms in the documentation antenna terms used in all documentation DDJF Test Report Test Procedures ICD and EIDP shall follow the definitions found in the IEEE Standard 145 1993 Antenna Terms 7 2 1 2 2 Engineering process The following engineering process shall be applied a Perform an analysis of the mission requirements for signal transmission and reception for all systems and payload for all phases of the mission b Perform electrical mechanical and thermal computer assessments to identify feasibility and performance margin for the whole antenna farm Establish performance budgets including losses simulation measurement error and technology maturity margins for the whole antenna farm d Establish prediction measurement and operational pointing excitation phase centre etc as applicable error accuracy budgets for the whole antenna farm e Establish a plan for the maintenance and periodical review of the budgets established in requirement c and d above during all project phases 7 2 13 Failure containment and redundancy a Antennas are in general single point failure elements therefore their failure rates shall be agreed with the customer specified and demonstrated NOTE To improve the failure rate special precautions in the redundancy architecture are commonly taken to cover the failures of active elements 65 DRAFT
32. to the loss of the mission or human injury shall be verified by test simulating the failure event f Stimuli points on equipment and payload shall not provoke unwanted operation g The protection of functions which failure can lead to the loss of the mission or human injury shall be verified by test simulating the failure event h The test of a protection function or a redundant function shall present no risk of stress or failure propagation due to the injection of stimuli 1 1 Hot redundant functions and protection functions shall be tested up to the highest possible level of integration of the unit 2 Hot redundant functions and protection functions that cannot be tested beyond unit level shall be identified in the critical item list Js Redundant functions and protection functions within a unit shall be verified by test at unit level NOTE Tests can be performed at open unit or closed unit levels Redundant units within a system shall be verified by test at system level 1 Protection functions within a unit protecting other units shall be verified by test at system level 23 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss 4 2 5 Mechanical 4 2 5 1 Wired electical connections Wired electrical connections shall contain stress relief NOTE The objective is to avoid excessive mechanical loads on wires 4 2 6 Dependability a Each item shall be directly interchangeable in form fit and function with othe
33. 20B rev 1 17 April 2008 5 7 3 3 2 Design and Verification RF components and equipments of the RF chain shall be designed and verified to withstand the maximum specified operating RF power levels plus safety margins agreed with the customer in the development phase 7 3 4 Qualification for power handling and gas discharge The following criteria shall be met for qualification for power handling and gas discharge d The RF component and equipment has no physical degradation e The RF component and equipment has no degradation of the RF performance during and after the test 7 4 Passive intermodulation 7 4 1 Overview Passive intermodulation products are generated when two or more RF transmit signals illuminate or passing through a non linear passive RF component The RF frequencies of the passive intermodulation products are derived as for any other generation of intermodulation products when two or more RF signals are present simultaneously However the power levels of the passive intermodulation products depend on the materials used manufacturing tolerances and processes assemble techniques and oxidation of surfaces Thus they are hardly predictable implying that verification by test is mandatory for those intermodulation products that can adversely impact the mission or cause interference in third party protected frequency bands 7 4 2 General requirements a The acceptance level of interference caused by passive interm
34. 3 1 3 antenna RF chain sequence of microwave components ortho mode transducers polarisers transformers as well as filters inserted between an antenna input port or a BFN output port and a corresponding individual radiating element 3 1 4 antenna support structure an antenna support structure is a part of an antenna having no electrical function which may however impact its electrical performances of the antenna either directly due to scattering or indirectly e g due to induced thermo elastic deformations 3 1 5 array antenna an array antenna is defined as an antenna composed by a number of possibly different elements that radiate RF signals directly into free space operating in combination i e such that all or a part of them radiate the same signals DRAFT ECSS E 20B rev 1 17 April 2008 5 3 1 6 array fed reflector antenna an array fed reflector antenna sometimes known in the technical literature as hybrid antenna is defined as an antenna composed by a feed array which may or may not include a beam forming network and one or more optical elements reflectors and lenses 3 1 7 beam forming network BFN a RF beam forming networks is a wave guiding structure composed a chain of microwave components and devices lines phase shifters couplers loads aimed at distributing the RF power injected at the input ports to a number of output ports in a transmitting antenna the RF power injected from the t
35. 8 A T 3 5 5 7 5 b A T 3 5 5 7 5 c A T 3 5 5 7 5 d RoD A T 3 5 5 7 5 e A T 3 5 5 7 5 1 amp 2 3 5 7 5 8 RoD A T 3 41 5 5 7 5 h RoD A T 3 5 5 7 6 a RoD A T 3 41 5 5 7 6 b RoD T 315 5 7 6 1 RoD T 315 5 7 6 c 2 3 5 8 1 A INS 3 5 8 1 1 amp 2 3 5 8 1 c A INS 3 5 8 1 d 3 5 8 1 6 3 5 8 1 f INS 3 5 8 1 2 RoD A T 3 5 5 8 1 h 3 5 8 1 1 3 5 8 14 3 8 1 1 RoD T 31151 5 8 1 k 2 3 5 8 11 RoD A T 3 5 5 8 1 m RoD A T 3 5 5 8 1 0 A T 3 5 5 8 1 0 A or T 3 5 5 8 1 RoD A T 3 5 5 8 1 q 3 5 8 2 INS 3 55 DRAFT ECSS E 20B rev 1 17 April 2008 5 8 2 b INS 3 5 8 2 c INS 3 5 8 2 4 3 5 8 2 e 3 5 8 2 f TRR T 5 5 8 2 g INS 3 5 8 2 INS 3 5 8 9 1 INS 3 5 8 2 INS 3 5 10 SRR
36. Draft ECSS E 20B rev 1 17 April 2008 EUROPEAN COOPERATION FOR SPACE STANDARDIZATION Space engineering Electric and electronic Revision 1 Table in 4 4 2 corrected A column was missing As well Table numbering corrected DISCLAIMER This document 1s an ECSS Draft circulated to the ECSS Technical Authority for approval for publication at the end of the benchmarking phase It 15 therefore subject to change without any notice and may not be referred to as an ECSS Standard until published as such End of TA approval for publication 29 April 2008 ECSS Secretariat ESA ESTEC Requirements amp Standards Division Noordwijk The Netherlands DRAFT ECSS E 20B rev 1 17 April 2008 fAcss Published by ESA Requirements and Standards Division ESTEC P O Box 299 2200 AG Noordwijk The Netherlands Copyright 2008 by the European Space Agency for the members of ECSS DRAFT ECSS E 20B 1 CSS 17 April 2008 Foreword This Standard is one of the series of ECSS Standards intended to be applied together for the management engineering and product assurance in space projects and applications ECSS 18 a cooperative effort of the European Space Agency National Space Agencies and European industry associations for the purpose of developing and maintaining common standards Requirements in this Standard are defined in terms of what shall be accomplished rather than in terms of how to organize and perf
37. ECSS E 20B rev 1 17 April 2008 7 2 2 Antenna structure 7 2 2 1 General The antenna category 7 2 2 2 composing elements 7 2 2 2 4 used technologies 7 2 2 4 and the performance parameters 7 2 2 5 shall be established at the beginning of the project phase B 7 2 22 Categories TI amp C and data transmission The antenna radiation pattern shall be characterised including the scattering effects of all surrounding structures TT amp C and data transmission antennas are in general compact antennas individual radiating elements 7 2 2 3 1 with broad radiation patterns and a single beam In some cases e g deep space missions more complex antennas falling into one of the other categories are used If a number of TT amp C antennas operate simultaneously the combined radiation pattern shall be used in the performance evaluation Reflector Lens antennas The reflection and transmission properties losses depolarisation and diffusivity of the reflecting or transmitting elements shall be quantified and their impact on antenna performances assessed Reflector Lens antennas are constituted by one or more radiating elements 7 2 2 3 1 possibly including an antenna RF chain Error Reference source not found one or more partially reflecting or transmitting elements reflectors 7 2 2 3 2 lenses 7 2 2 3 3 and an antenna support structure in one or more portions 7 2 2 3 6 If several radiating elements are
38. EMC verification including outline of system level EMC test plan including rationale for selection of critical circuits for safety margin demonstration and instrumentation techniques for both critical and EED circuit sensitisation 80 DRAFT ECSS E 20B rev 1 17 April 2008 5 Annex B nomative Electromagnetic effects verific ation plan EMEVP DRD B1 DRD identification 1 1 Requirement identific ation and source document ECSS E 20B subclause 6 4 1 B 1 2 Purpose and objective This document defines the approach methods procedures to verify electromagnetic effects This Document Requirements Definition DRD establishes the data content requirements for the Electromagnetic Effects Verification Plan EMEVP This DRD does not define format presentation or delivery requirements for the Electromagnetic Effects Verification Plan This DRD is applicable to all projects using the ECSS Standards The electromagnetic effects verification plan provides the instruction for conducting all activities required to verify that the effects of the electromagnetic environment are compatible with the requirements of the project 82 Expected response B 2 1 Response identification The requirements for project identification contained in ECSS M 50 shall be applied to the Electromagnetic effect verification plan EMEVP B 2 2 Scope and content The EMEVP shall provide the information presented in the following sections
39. JF Test Report 1 2 2 2 8 a A T PDR CDR DDJF Test Report 7 2 2 2 3 b A T PDR CDR DDJF Test Report 7 2 2 2 3 A T PDR CDR DDJF Test Report 7 2 2 2 4 RoD PDR DDJF 7 2 2 3 1 a A T PDR DDJF 7 2 2 3 1 b A T PDR CDR DDJF Test Report 7 2 2 3 1 A T PDR CDR DDJF Test Report 7 2 2 3 1 d A PDR CDR DDJF Test Report 7 2 2 3 1 A T PDR CDR QTR FAR DDJF Test Report 1 2 2 3 1 f A T PDR CDR QTR FAR DDJF Test Report 7 2 2 3 1 8 T PDR CDR QTR FAR ICD Test Report 7 2 2 3 2 a A T PDR CDR DDJF Test Report 7 2 2 3 2 b A T PDR CDR DDJF Test Report 7 2 2 3 2 A PDR CDR DDJF Test Report 7 2 2 3 3 a A T PDR CDR DDJF Test Report 7 2 2 3 3 b A PDR CDR DDJF 72 DRAFT ECSS E 20B rev 1 17 April 2008 1 2 2 3 3 c RoD T PDR CDR QTR FAR DDJF Test Report ICD 1 2 2 3 3 d RoD T PDR CDR QTR FAR DDJF Test Report ICD 1 2 2 3 4 a A T PDR CDR DDJF Test report 1 2 2 3 4 b A PDR CDR DDJF 1 2 2 3 4 c A PDR CDR DDJF 1 2 2 3 4 d A T RoD PDR CDR QTR FAR DDJF Test Report 1 2 2 3 5 a A T PDR CDR DDJF Test Report 1 2 2 3 5 b A T PDR CDR DDJF Test Report 1 2 2 3 5 A T RoD PDR CDR QTR FAR DDJF Test Report 1 2 2 3 6 a A T PDR CDR DDJF Test Report 1 2 2 3 6 b A T PDR CDR DDJF Test Report 1 2 2 4 1 a A T RoD PDR CDR QTR FAR DDJF Test Report EIDP 1 2 2 4 1 b A T RoD PD
40. R CDR QTR FAR DDJF Test Report EIDP 1 2 2 4 1 c A PDR CDR DDJF 1 2 2 4 2 a A PDR CDR DDJF 1 2 2 4 2 b A PDR CDR DDJF 1 2 2 4 2 c T RoD PDR CDR QTR FAR DDJF Test Report EIDP 1 2 2 4 3 a A T PDR CDR DDJF Test Report 1 2 2 4 3 b A PDR CDR DDJF 1 2 2 4 3 c T RoD PDR CDR QTR FAR DDJF Test Report EIDP 1 2 2 5 RoD PDR CDR QTR FAR DDJF Test Report 7 2 3 1 a A T RoD PDR CDR DDJF Test Report 7 2 8 1 PDR CDR QTR FAR DDJF Test Report EIDP 7 2 3 2 a A T PDR CDR DDJF Test Report 7 2 3 2 DDJF 73 DRAFT ECSS E 20B rev 1 17 April 2008 5 7 3 Power 7 3 1 Overview The objective of the following RF breakdown requirements is to ensure that the space system operates at maximum power levels without any risk of Multipaction RF power handling limitation and Corona also called discharge Multipaction requirements are described ECSS E 20 01A e power handling requirements are described in clauses 7 3 2 e Corona or Gas Discharge requirements are described in clauses 7 3 3 and apply for vented RF components during launch and pressurisation due to out gassing of the spacecraft or re entry pressurized RF components 7 3 2 RF Power handling thermal 7 3 2 1 General requirements the components and equipments of the RF chain shall be able to stand the maximum specified operating RF power during its application in sp
41. System engineering Part 1 Requirements and process Verification Testing Spacecraft charging EMC Photovoltaic assemblies and components Space engineering Mechanical Part 1 Thermal design Pyrotechnics Mechanical parts Materials Pressurized hardware Communications Part 1 Principles and requirements Configuration management Information documentation management Glossary of terms Quality assurance Space product assurance De rating and application rules Dependability Space product assurance Hazard analysis Safety ASIC and FPGA development EEE components Qualification of printed circuit boards Procurement of printed circuit boards The repair and modification of printed circuit board assemblies for space use Critical item control DRAFT ECSS E 20B rev 1 17 April 2008 5 3 Terms definitions and abbreviated terms 3 1 Temnsand definitions The following terms and definitions are specific to this Standard in the sense that they are complementary or additional with respect to those contained in ECSS P 001 B 3 1 1 antenna farm the antenna farm of a spacecraft 1s constituted by the ensemble of all antennas accommodated on the spacecraft and provides for all the transmission and reception of RF signals 3 1 2 antenna port an antenna port is the abstraction of the physical connection among the antenna and its feeding lines realised by means of connectors or waveguide flanges
42. a fully regulated bus shall not generate a bus voltage transient exceeding 2 of the nominal bus voltage NOTE Rationale for the requirement This is to respect the quality of the regulated bus Normal switching of a load unlike fuse blowing is not seen nor has the effect of an abnormal transient h If fuses are used to protect main bus distribution lines the design shall ensure that the power generation system can fuse them within less than 20 ms in case of load short circuit NOTE This to ensure compatibility with 5 7 4 a 1 Relays shall be protected such that the peak voltage across the contacts at switch off does not exceed the de rated voltage requirement of the relay ECSS Q 30 11A sub clause 6 25 or 1 1 times the switched voltage which ever is the lowest Equipment connected to independent redundant power buses shall ensure that 1 For unmanned missions single failure causes the loss of more than one power bus 2 For manned missions two failures do not cause the loss of more than one power bus k 1 current limiting devices and automatic switch off circuits shall be monitored by telemetry 2 The failure of the monitoring function shall not cause the protection elements to fail The stability of current limiters shall be ensured for the actual loads characteristics verified by analysis under worst case conditions and tested under a set of cases agreed with the customer m case t
43. ace with a no degradation of the component b no degradation of the RF signal including radiative losses and c with their thermal levels not exceeding those corresponding to the maximum available RF power at the maximum qualification temperature 7 3 2 2 Design and Verification Each element of the RF chain shall be designed and verified to withstand the maximum specified operating RF power levels plus safety margins agreed with the customer in the development phase at the maximum qualification temperature 7 33 Corona or Gas Discharge 7 3 3 1 General requirements a All the components and equipments of the RF chain shall be free of any risk of Gas discharge Corona at the maximum specified operating RF power over the full pressure range during 1 The depressurization of the RF components and equipments at launch environmental conditions 2 The pressurization due to out gassing of the spacecraft in orbit 3 Ground testing at ambient pressure and 4 The pressurization of the spacecraft during planetary re entry phases at the mission environmental conditions b For those components and equipments which design does not allow operating them over the full pressure range 1 The applicable pressure range and gas properties shall be specified 2 The design and manufacturing shall be performed to avoid discharge phenomena according to Pashen curves valid for its specified pressure range and gas properties 74 DRAFT ECSS E
44. al electronic electromagnetic microwave and engineering processes specifies the tasks of these engineering processes and the basic performance and design requirements in each discipline It defines the terminology for the activities within these areas It defines the specific requirements for electrical subsystems and payloads deriving from the system engineering requirements laid out in ECSS E 10 Part 1B Space engineering System engineering Part 1 Requirements and process DRAFT ECSS E 20B rev 1 17 April 2008 2 Normative references The following normative documents contain provisions which through reference in this text constitute provisions of this ECSS Standard For dated references subsequent amendments to or revisions of any of these publications do not apply However parties to agreements based on this ECSS Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below For undated references the latest edition of the publication referred to applies ECSS E 10 Part 1B ECSS E 10 02A ECSS E 10 03A ECSS E 20 06A ECSS E 20 07A ECSS E 20 08B ECSS E 30 Part 1A ECSS E 30 Part 6A ECSS E 30 Part 7A ECSS E 30 Part 8A ECSS E 30 02A ECSS E 50 Part 1A ECSS M 40B ECSS M 50B ECSS P 001B ECSS Q 20B ECSS Q 30 11A ECSS Q 30B ECSS Q 40 02 ECSS Q 40B ECSS Q 60 02 ECSS Q 60B ECSS Q 70 10A ECSS Q 70 11A ECSS Q 70 28A ECSS Q20 04
45. al function shall include noise discrimination filtering such that spurious commands of nominal peak to peak amplitude and of less than 10 of the nominal command duration at a repetition period of 40 of the nominal command duration are ignored The application of the nominal signals or a faulty signal as defined in the general design and interface requirements document to an un powered interface shall not cause damage to that interface NOTE In case verification by analysis is not conclusive a complementary verification by test is necessary DRAFT ECSS E 20B rev 1 17 April 2008 5 An undetermined status at the interfaces of a powered unit shall not cause damage to this unit NOTE Undetermined status includes non nominal operating modes permanent and non permanent failure modes powered and un powered interfaces NOTE In case verification by analysis is not conclusive a complementary verification by test is necessary f Signal interfaces shall withstand without damage positive or negative nominal voltages that are accessible on the same connector from the unit Itself from the interfaced units or from EGSE NOTE In case verification by analysis is not conclusive a complementary verification by test is necessary g Any circuit intended to receive a signal should include noise discrimination filtering compatible with susceptibility recommendations as defined in ECSS E 20 07A Annex A 4 13 Comman
46. also known as the factor 3 1 36 reflector antenna a reflector antenna is defined as an antenna composed by a number of reflecting surfaces RF reflectors illuminated by a primary source the feed 3 1 37 RF chain sequence of microwave components inserted between the RF power amplifier and the antenna input port 3 1 38 RF lens plastic composite or metallic e g waveguide array lenses structure acting on transmitted RF waves to control the antenna pattern 3 1 39 RF reflector an RF reflector is a metallic or composite structure possibly metallised or with printed or embedded metallic elements acting on reflected RF waves to control the antenna pattern NOTE Frequency and polarisation surfaces as well as other fully reflecting or partially reflecting and transmitting structures also having non uniform or anisotropic scattering behaviour are considered reflectors 13 DRAFT ECSS E 20B rev 1 17 April 2008 55 3 1 40 secondary cell or battery A battery or cell that is designed to be charged and discharged multiple times 3 1 41 solar cell assembly SCA solar cell together with interconnector coverglass and if used also a by pass diode 3 1 42 susceptibility any malfunction degradation of performance or deviation from specified indications beyond the tolerances indicated in the individual equipment or subsystem specification in response to other than intended stimuli 3 1 43 susceptibility thres
47. an the probability of a failure of the cell 2 If the bypass operation is not instantaneous the power system design shall be able to operate without damage during the transient situation 3 The maximum number of cells that can be bypassed after a failure or a wrong command shall be equal to the number of failures allowed by the specific mission design f Transient currents occurring when two or more separate strings of series connected cells are connected together in parallel or when a cell fails short circuit in a battery composed of parallel strings shall not result in exceeding the peak cell current rating g Procured battery cells shall be originating from the same production lot with the same operational history NOTE Cells making up a battery are selected matched in accordance with the cell manufacturer s requirements Sufficient extra matched spare cells are procured to allow for replacement of any cells damaged during integration of batteries If cells are not individually replaceable then appropriately matched cell groups modules are available It is good practise to specify the number of spare cells in the battery procurement documentation h When individual batteries are discharged in parallel imbalance between the battery cells shall not result in current and temperature exceeding the cell qualification limits 1 Conducting cases of battery cells in a battery package shall be double insulated from each other
48. and from battery structure with an insulation between any cell and the structure greater than 10 measured at 500 V DC Js The battery design shall include the following provisions for interfacing with the ground support equipment during pre launch operations signal lines for monitoring battery voltage battery temperature capability to charge or discharge the battery cell or cell group voltage monitoring protected by current limitation 36 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss logbook shall be maintained by the supplier for each flight battery starting with the first activation after battery assembly up to launch describing chronologically all test sequences summary of observations identification of related computer based records malfunctions and references to test procedures and storage conditions NOTE The logbook is used for the following purposes to ensure compliance with storage handling and operational requirements before launch e g maximum time allowed at upper temperature limits correct scheduling of maintenance activities to allow verification of flight worthiness special has to be paid to external current discharge paths during integration phases Battery thermal design shall ensure that 1 maximum and minimum qualification temperature of cell operation under intended cycling conditions are not exceeded 2 maximum qualification temperature gradi
49. anical EEE components Space product assurance Qualification of printed circuit boards Space product assurance Procurement of printed circuit boards Space product assurance Control of limited shelf life material Space product assurance The repair and modification of printed circuit board assemblies for space use JPL Publication 86 14 NASA Aerospace Battery Safety Handbook G Halpert S Subbarao amp J Rowlette 86 DRAFT ECSS E 20B rev 1 17 April 2008 SPIE Vol 2210 IEEE 145 1993 IEEE 95 1 1991 IEEE 149 1979 R 1990 IEEE Std 145 1993 IEC 60825 IEC 60479 Optical design and technologies for space instrumentation Csichy Standard definitions of terms for antennas Safety levels with respect to human exposure to radio frequency electromagnetic fields 3 kHz to 300 GHz Test procedures for antennas Antenna Terms Safety of laser products Effects of current on human beings and livestock 87
50. ay regulators battery chargers and dischargers the phase margin shall be at least 60 and the gain margin 10 dB for worst case end of life conditions with representative loading b The phase margin of converters and regulators not belonging to the spacecraft power system shall be at least 50 and the gain margin 10 dB for worst case end of life conditions with representative loading NOTE Rationale for this requirement The condition expressed in requirement a and b above assumes that the converter has a monotonic decreasing transfer function for which the sufficient condition of the Nyquist criterion can be applied It indirectly encourages the designer to make designs for which the verification of the stability is simple A higher quality is used for converters driving the bus quality and in particular 60 is selected to minimize the overshoot in the response The electrical zero volt reference of isolated converters and regulators shall be isolated from the unit case by more than 10 per converter NOTE Rationale for this requirement The value of 10 is a compromise to be very large in DC and low frequency to minimize ground loop currents and to be small for high frequencies above 5 MHz in order to minimize the volt drop between references due to common mode currents 45 DRAFT ECSS E 20B rev 1 17 April 2008 5 4 The capacitance between the zero volt reference of isolated converters and
51. ch phases shall be according to those described in the applicable launchers user s manuals NOTE Specific EMC requirements during the pre launch and launch phase are described in an Interface Control Document established on a contractual basis between the launching company and the customer 6 3 2 3 Protected frequency bands For protection of radiometric and communication bands ECSS E 50 05A paragraph 5 5 shall be applicable 6 3 2 4 Lightning The space system shall be protected against both direct and indirect effects of lightning such that the mission is without degradation of performances after exposure to the lightning environment 6 3 3 Hazards of electromagnetic radiation The space system shall be designed so that humans fuels explosive systems and electronically actuated thrusters are not exposed to hazards of electromagnetic radiation present in the entire electromagnetic environment including interference sources from possible external transmitters 6 3 4 Spacecraft charging protection program 6 3 41 Applicability A spacecraft charging protection programme shall be produced by the supplier for the PDR and submitted to the customer for approval for all the space systems encountering a space charging environment 1 6 a Earth orbits above 8000 km b Earth orbits above 40 degrees latitude c Jupiter encounters closer than 15 Rj Jupiter radii and d other planets plasma and dust charging as specified by the
52. ct SRR applied and kept under configuration control throughout the whole project b The margin for available memory size and load factors of processors should be 1 for new developments 50 as a minimum at new board software parts 2 25 at launch The margin on the throughput of on board communication networks should be l for new developments 50 as a minimum at on the average throughput 2 such that real time overflow is avoided d In the absence of specific mission requirements the following applies After error correction reset or data corruption of main functions at equipment level should be kept to a rate of occurrence less or equal to 1074 per day for worst case conditions of environment e For programmable logic devices the available margin of unused blocks and margin with respect to clock frequency and propagation time should be for new developments 50 as a minimum at 4 2 3 Hectical connectors a A connector carrying source power or external test connectors on units shall have no contact areas exposed to possible short circuit during mating and de mating process NOTE They generally are female type connectors b external test connectors on a unit shall be covered for flight c The test connector covers should be metallic or metallized and grounded to structure d The use of a connector saver for ground testing shall not alter the performance of the equipmen
53. ct on the antenna performances b For all high power applications the risk of generation of passive inter modulation products by the surrounding spacecraft structure and appendages shall be assessed starting from Phase B as a minimum and the impact on antenna performances assessed 7 2 4 Antennas Verification The requirements of this Clause 7 2 shall be verified by the verification methods at the reviews and recorded in the documents as specified in Table 7 1 NOTE For verification see also ECSS E 10 02 71 DRAFT ECSS E 20B rev 1 17 April 2008 Table 7 1 Antennas verification requirements Requirement Verification method At review Recorded in A PDR 1 Antenna ICD T CDR 2 EIDP RoD QTR 3 DDJ F 4 Tests Reports 5 Specification 7 2 1 1 RoD PDR DDJF 121341 RoD Maintained through all DDJF reviews 121234 RoD Maintained through all DDJF reviews 1 2 1 2 2 b RoD PDR DDJF 1 2 1 2 2 c RoD A PDR CDR DDJF 721224 RoDA 7 2 1 2 2 RoD CDR DDJF 029 1 2 1 3 a T CDR Test Report ERE LC PRE 7 2 1 3 b A PDR DDJF 1 2 2 1 RoD PDR CDR DDJF 1 2 2 2 1 a A T PDR CDR DDJF Test Report 7 2 2 2 1 A T PDR CDR DDJF Test Report 1 2 2 2 2 a A T PDR CDR DDJF Test Report 1 2 2 2 2 b A T PDR CDR DDJF Test Report 1 2 2 2 2 c A T PDR CDR DD
54. d by the manufacturer of an energy storage cell or battery NOTE It is given in ampere hours It is not necessarily equal to any measurable capacity 3 1 29 non essential loads The non essential loads are related to units which do not implement essential functions for the spacecraft 3 1 30 passive intermodulation products PIM passive intermodulation products PIM are the spurious signals generated by non linear current voltage characteristics in materials and junctions exposed to sufficiently RF high power carried by guided or radiated fields and currents possibly triggered by microscopic mechanical movement DRAFT ECSS E 20B rev 1 17 April 2008 5 3 1 31 photovoltaic assembly PVA power generating network comprising the interconnected solar cell assemblies strings and sections the shunt and blocking diodes the busbars and wiring collection panels the string section and panel wiring the wing transfer harness connectors bleed resistors and thermistors 3 1 32 Primary cell or battery A battery or cell that is designed to be discharged once and never to be recharged 3 1 33 radiofrequency RF frequency band used for electromagnetic waves transmission 3 1 34 radiated emission RE radiation and induction field components in space 3 1 35 recharge ratio k ampere hours charged divided by the ampere hours previously discharged starting and finishing at the same state of charge NOTE Itis
55. d measuring electrical electronic and mechanical outputs of equipment and subsystems to be monitored during the test programme description of cables attached to the equipment under test definition of the line impedance stabilization network values of internal components need for calibration and check of the measurement setup antennas to use for RF emission and susceptibility tests 82 DRAFT ECSS E 20B rev 1 17 April 2008 Method of switching ON for inrush current testing 83 DRAFT ECSS E 20B rev 1 17 April 2008 55 Annex normative Electromagnetic effects verific ation report EMEVR DRD C 1 DRDidentification C L1 Requirement identific ation and source document ECSS E 20B subclause 6 4 1 C 1 2 Purpose and objective This Document Requirements Definition DRD establishes the data content requirements for the Electromagnetic Effects Verification Report EMEVR This DRD does not define format presentation or delivery requirements for the Electromagnetic Effects Verification Report This DRD 15 applicable to all projects using the ECSS Standards The electromagnetic effects verification report provides reporting of all activities in relation with the verification of the effects of the electromagnetic environment The document is prepared for each project based on the electromagnetic effects verification plan It then applies to every item of equipment and subsystem in the pr
56. ds a Every command intended to be sent to the spacecraft shall be assessed for criticality at equipment level and confirmed at subsystem system level NOTE The criticality of a command is measured as its impact on the mission in case of inadvertent function erroneous transmission incorrect function aborted transmission or loss of function The definition of criticalities can be found in Table 1 of ECSS Q 30C and 55 040 b All executable commands shall be explicitly acknowledged by telemetry High Priority telecommand decoding and generation shall be independent from the main on board processor and its software NOTE That implies the high level command decoder command generator and their power supply to be entirely implemented in a dedicated module in a secure and independent way d With the exception of pyrotechnic commands the function of an executable command shall 1 not change throughout mission and 2 not depend on the history of previous commands DRAFT ECSS E 20B rev 1 17 April 2008 5 For commands of category 1 and 2 criticality at least two separate commands for execution an arm safe or enable disable followed by an execute command shall be used NOTE For criticality categories see ECSS Q 40C Tablel f It shall be possible to repeat the transmission of all the executable commands without degradation of the function or a change of its status g In case of critical commands
57. e voltage limit above which taper charging begins can be adjusted as a function of temperature ageing or other parameters depending on the battery technology In some missions required lifetime can only be obtained if the taper charge limit 15 lowered during periods of no or little battery use e The charging technique shall ensure that the applied recharge ratio does not violate the manufacturer s requirements for the particular cell technology operational temperature and cycle life f The charging technique shall ensure that any lifetime related maximum cell voltage and temperature limits as stated by the manufacturer for the adopted technology are respected g The battery charge current and end of charge control shall be autonomous and one fault tolerant two failure tolerant for manned mission h The ultimate over charging discharging protection circuitry shall be implemented by hardware and independent from any on board software 1 Battery Charge and Discharge Management shall be such that a single failure does not impair the lifetime of the energy storage system with respect to minimum or maximum voltage as well as maximum charge or maximum discharge current NOTE Such failure tolerance can be implemented at cell battery or subsystem level 5 7 4 Bus under voltage or over voltage a For fuse protected busses the delay before non essential loads disconnection in the event of a bus undervoltage of more than 10 below
58. electrolytes or toxic endangering any nearby personnel as well as neighbouring equipment The principal cell failure modes which can lead to these effects are listed in 5 6 5 2 b Detailed descriptions of the hazards associated with different battery chemistry are given in reference document Crew Vehicle Battery Safety Requirements JSC 20793 Rev B April 06 The design rules in earlier sections which aim at maximizing battery performance and cycle life also reduce the possibility that cells and batteries exhibit failure modes such as those listed above However in applying the safety rules of ECSS Q 40B some battery failure modes are critical and or catastrophic Further design or management provisions are implemented to achieve the required level of fault tolerance For safety requirements related to pressure vessels see ECSS E 30 part 02A 5 6 5 2 Provisions a All potential failure modes and their possible consequences to personnel and equipment shall be identified and reported in the battery safety and hazard report to be provided by the battery supplier NOTE The potential failure modes include the ones listed in b below b The design of the battery and associated monitoring and control electronics shall preclude the occurrence of any of the following 1 Over temperature from battery thermal dissipation environmental heating 2 excessive currents discharge or charge including short circuit external or inter
59. ents between different parts of the same cell and between two cells in a battery are not exceeded m battery mechanical design shall ensure that cell stress and fatigue limits are not exceeded 5 6 3 Battery cell a Absolute maximum ratings of the cell in term of voltage charge and discharge current continuous and peak temperature shall be defined b The ability of a cell to meet mission lifetime requirements where not covered by qualification life testing or previous in flight experience shall be justified by the ground test data or by dedicated tests under representative conditions The ability of a cell to meet mission life time requirements may be verified by similarity with qualification life testing or previous in flight experience only in case of identical design and identical manufacturing processes d 1 For any intended cell operation under acceleration greater than 1 g the supplier shall ensure that no effect upon both short term e g capacity performance and lifetime can prevent battery nominal operation 2 In case verification by analysis is not conclusive a complementary verification by test shall be performed e Any special in flight measures to ensure that the batteries meet their performance requirements e g in orbit reconditioning for Ni Cd and Ni H2 cell state of charge balancing for some lithium ion technologies that impose operational constraints shall be identified at system level for
60. evel k Provision shall be taken to avoid arcing or short circuits in connectors NOTE For example Unused pins placed between positive and return lines specific connector design The following shall be performed for any connector the loss of which can lead to the loss of the mission l Document the connector in the single point failure list 2 Verify its integrity up to the highest spacecraft integration level m accidental de mating of connectors where it is a realistic case or any internal connector failure shall not lead to catastrophic consequences n Battery and Solar array power shall be distributed by multiple contacts on both positive and return lines 22 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss 4 2 4 Testing a Test stimulus points shall be 1 accessible without the need of modifying the electrical configuration of an item of equipment and 2 protected for flight operation b For the purpose of meeting requirement a above dedicated test connectors should be used The functionality shall be provided to test the redundant function of a closed unit d Test points on equipment shall 1 be protected against damage up to the maximum fault voltage present on the connector either coming from the equipment or the EGSE and 2 be such that unintentional connection of these points to ground does not damage the equipment e The redundancy of parts and functions which failure can lead
61. ficient Temperature Current amp Voltage Direct Gradient on String NOTE Typical value is 3 including secondary working standard calibration and bare solar cell measurement accuracies Orbital losses as EQX SS altitude inclination albedo solar array angle including the cosine law deviation e g High Low Intensity interplanetary mission 4 e g Voltage losses due to cells and solar cell shunt diodes For the average operational temperature on orbit 5 g For recently developed solar cells and produced in large scale the string current calculation shall include as a random parameter the increase of solar cell performance h In addition with the parameters indicated in Table 5 1 the EOL worst and best case calculations shall include the parameters indicated in Table 5 2 33 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss Table 5 2 Additional power parameters for EOL worst and best case calculations Parameter Appie hie SRM to string loss gain UV degradation Current Direct Micrometeorites Current Direct Loss of strings tolerance Current Direct Reliability of components Current amp and interconnection Voltage Degradation due to ESD Current amp Random Phenomena Voltage Solar array surface Current Direct contamination mu Current amp Direct Radiation Voltage Typical value 0 25 loss per year
62. fined by the customer with the minimum of one string lost and one battery cell failed during all the designed life of the power system including all spacecraft modes of operation f When using a MPPT the power and energy budgets shall include the reduction of transferred power due to the differences in IV curves of the different strings and panels leading to multiple local Maximum Power Points and mismatches 5 3 Failure containment and redundancy a Any protection function of a power converter or regulator preventing failure propagation shall l not be implemented in the same hybrid cavity or integrated circuit and 2 not utilize common references b It shall not be possible to inhibit a protection feature which can lead to the loss of the main primary power bus in case of a single failure at spacecraft level c In flight operation the power system shall be able to start up from any of its power sources irrespective of the status of the other power source even after a failure or after a double failure for manned mission d The supplier shall submit for customer approval the list of single failure cases or double failure cases for manned missions against which the requirement c shall be fulfilled 29 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss 54 Hectical power interfaces a The electrical power interface between the solar array s and the power control units and between batteries and power control units shall
63. ges of the function to be commanded are in the operational nominal range 4 1 4 Telemetry a Telemetry data devoted to the Spacecraft Subsystem and Payloads monitoring shall allow 1 the retracing of the overall configuration at least up to all reconfigurable elements 2 the location of any failure able to impact the mission performances and reliability at least up to all reconfigurable elements b The operational status On Off enabled disabled active not active of each element of any telemetry acquisition chain should be provided to the on board computer in order to determine without ambiguity the validity of the telemetry data at the end of the overall chain Main bus load currents shall be monitored by telemetry to enable together with the bus voltage telemetry a complete monitoring of a main bus power load d Telemetry shall be implemented to monitor the evolution of the 18 DRAFT ECSS E 20B rev 1 17 April 2008 4 2 Design power energy resources and the source temperatures during the mission 4 2 1 Failure containment and redundancy a A single failure shall not propagate outside a single reconfigurable element Redundant functions shall be routed separately Provision b above should be met via redundant harness and physically separated connectors Redundant functions shall be physically separated with no risk of failure propagation by thermal or other coupling and as a minimum contained
64. ground reference concept including the definition of circuit and unit categories shall be specified and agreed with the customer for the spacecraft prior to initial release of the EMC control plan 6 3 8 3 Wiring Detailed requirements are specified ECSS E20 07 clause 4 13 1 Classification of cables and clause 4 2 13 2 Cable shields 6 3 9 Detailed design requirements EMC detailed system design requirements are specified in ECSS E 20 07 62 DRAFT ECSS E 20B rev 1 17 April 2008 055 6 4 Verification 6 4 1 Verification plan and report a The verification plan shall be accomplished by the supplier in the frame of the EMC programme b The verification plan shall be documented in the Electromagnetic Effects Verification Plan using DRDs in Annex B An Electromagnetic Effects Verification Report using DRDs in Annex shall be prepared by the supplier 6 42 Safety margin demonstration for critical or EED circuit a Safety margins for critical or EED circuit shall be demonstrated at system level b If the demonstration of safety margins is done by test the spacecraft suite of equipment and subsystems shall be operated in a manner simulating actual operations agreed with the customer 6 4 3 Detailed verification requirements Detailed verification requirements are defined in ECSS E 20 07 63 DRAFT ECSS E 20B rev 1 17 April 2008 55 7 Radio frequency systems 7 1 Functional description
65. he distribution lines are protected by latching or periodically reset current limiters it shall be ensured by worst case analysis and test that the inrush energy demanded by the load in normal switch on does not cause the trip off of the latching protection with a margin of 20 n When indefinitely resetable current limiters are used instead of foldback current limiters the periodicity of resets after a fault condition shall be such that l no system EMC requirement is violated 2 the thermal stress resulting from the failed load current does not compromise the limiter operation i e components remain within their de ratings 48 DRAFT ECSS E 20B rev 1 17 April 2008 5 0 In case the distribution lines are protected latching foldback or periodically reset current limiters it shall be verified by analysis or test that the transient current peaks at current limiter intervention are within the rated stress limits of the components used for the worst case condition minimum series impedance case When protection elements are in cascade the closest one upstream from the anomaly shall be the first to act q When protections are used in cascade from a power source to a function to be supplied the compatibility of these protections shall be analysed 5 8 2 a No piece of harness shall be used as a mechanical support b With the exception of the solar array routing of power lines shall be near gr
66. hold interference level at a test point which just causes malfunction in the equipment subsystem or system 3 1 44 vacuum environment with a pressure of 10 Pa or below 3 2 Abbreviated terms The following abbreviated terms are defined and used within this Standard Abbreviation Meaning A analysis AC alternative current BEN beam forming network BOL beginning of life CDR critical design review DC direct current DDJF design description amp justification file DOD depth of discharge DRD document requirement definition DRL document requirement list EED electro explosive device EGSE electrical ground support equipment EIDP end item data package EMC electromagnetic compatibility EMEVP electromagnetic effects verification plan EMEVR electromagnetic effects verification report EMI electromagnetic interference EOL end of life EPS electrical power system DRAFT ECSS E 20B rev 1 17 April 2008 ESA ESD FAR FCL FDIR FMECA GDIR INS ICD IST LCL MPPT MRB PCB PDR PIM PVA QTR RF ROD SAD SCA SEE SEU SRR TRB TRR TM amp TC VCD European space agency electrostatic discharge flight acceptance review fold back current limiter failure detection isolation and recovery failure mode effect and criticality analysis general design and interface requirement inspection interface control document integrated system test current voltage latching current limiter maximum power point tracker
67. in a unit shall be defined FMECA shall be performed and based on the failure modes previously defined at component level 24 DRAFT ECSS E 20B rev 1 17 April 2008 Table 4 1 General verification requirements Requirement Treated at the Treated by the Recorded in following following verification points verification methods SRR RoD 1 Electrical ICD including SAR ICD PDR and Battery ICD CDR A 2 Budget documents TRR INS Power Energy Processor TRB memory budgets DRB NOTES ete FAR RoD includes review of 3 DDJ F documentation 4 GDIR X Preliminary formal verification point 5 Tests Reports 6 Specification 7 User manual 4 1 2 8 SRR RoD A T 11 3 4 1 5 6 4 1 2 b SRR RoD 4 4 1 2 c SRR RoD A 11113114 4 1 2 d PDR A T 3 5 4 1 2 6 RoD A T 3 4 5 4 1 2 f PDR RoD A T 3 4 5 4 1 2 g PDR RoD A 3 4 1 3 a SRR RoD A 3 4 6 4 1 3 b SRR RoD T 3 4 5 6 4 1 3 c PDR CDR RoD 3116 4 1 3 4 PDR CDR RoD 11113 4 1 3 6 CDR 11 421284 PDR CDR RoD A T 3 5 6 4 1 3 5 CDR 316 4 1 3 6 13116 4 1 3 1 CDR 3 5 6 4 1 3 j PDR CDR RoD A T 3 5 4 1 4 a PDR CDR RoD A 3 4 1 4
68. in orbit Depending of in orbit available data for each type of cell See ECSS E 10 04A sub clause 9 2 1 Shadowing and hot spot phenomena shall be analysed Leakage losses of bypass diodes shall be deducted from the power computation if they represent more than 0 1 of the overall power to be provided k Plume impingement effects shall be analysed 34 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 4 Solaramay drive mechanisms a The qualified de rated current capability of slip ring contacts shall be greater than the best case BOL solar array section current in short circuit and use transient currents caused by the discharge of the solar array section capacitance b The design of the insulation barriers between adjacent slip rings shall be such that no discharge phenomena can occur c Where non insulated conductors are used arcing phenomena shall be prevented by design 5 6 Hectroochemical Energy Storage 5 6 1 Applicability For the purpose of this subclause a battery is defined as a device that converts the chemical energy contained in its active materials into electric energy by means of electrochemical oxidation reduction redox reaction It is made up of one or more electrochemical cells which can be grouped in modules permanently connected in series and or parallel Subclauses 5 6 1 to 5 6 4 apply to primary and secondary batteries where reference is not made to charge Subclau
69. is designed to ensure no static error in higher frequency between 10 kHz and 100 kHz it is likely that the inductance effect of the components and connections are seen and the impedance rise not always making feasible to respect the ideal impedance mask Frequency Nominal regulated output voltage Volt P Power capability Watt Figure 1 Output impedance mask Ohm 42 DRAFT ECSS E 20B rev 1 17 April 2008 5 For unregulated buses the following parameters shall be specified analysed and tested 1 Maximum and minimum bus voltage guaranteed at payload level in all steady state and transients conditions 2 Maximum ripple in time domain Measured with at least 1 MHz bandwidth 3 Maximum spikes in the time domain superimposed on the bus voltage Measured with an analogue oscilloscope of 50 MHz minimum bandwidth or a digital oscilloscope offering equal or better performance 4 Impedance mask NOTE Rationale for the requirement Also for an unregulated bus it 15 important to identify the bus impedance mask to verify the compatibility between the power bus and the loads as for instance the guaranteed voltage range at bus level including the effects of load variations p During integration phase the power system shall be able to start up from any of its power sources irrespective of the connection of the other power source q In the case of an unexpected battery disconnection during ground
70. mance measurement e Thermal dissipation of RF power shall be quantified and the impact on antenna performances assessed 67 DRAFT ECSS E 20B rev 1 17 April 2008 5 f Whenever a radiating element is used to route high power levels 1 The applicable pressure range and gas properties shall be specified 2 The design and manufacturing shall be performed to avoid discharge phenomena according to Pashen curves valid for its specified pressure range and gas properties NOTE See section 7 3 for further details g All metallic parts in a radiating element shall be connected to the equipment DC ground to avoid Electrostatic Discharge ESD 7 2 2 3 2 RF Reflectors a Reflective properties losses depolarisation and diffusivity of the materials and or composites used shall be quantified and their impact on antenna performances assessed b The reflective and transmissive properties losses depolarisation diffusivity of the materials and or composites used for polarisation and frequency selective reflectors shall be quantified and their impact on antenna performances assessed e Deviations from the nominal geometry of the reflector shall be quantified and their impact on antenna performances assessed NOTE Reflectors can require hold down release deployment as well as pointing devices ECSS E 30 Part 6A and ECSS E 30 Part 7A are relevant and applicable in this case NOTE Typical deviations are due to
71. methods a Conducted emission on power leads in the frequency domain b Inrush current on power leads c Common mode conducted emission on power and signal leads d Conducted emission on antenna ports e DC magnetic field emission f Radiated magnetic field emission in the low frequency range scientific spacecraft _ Radiated electric field emission in the low frequency range scientific spacecraft 79 DRAFT ECSS E 20B 1 CSS 17 April 2008 h Radiated emission of RF electric field 1 Conducted susceptibility on power leads in differential mode 0 Conducted susceptibility on power and signal leads in common mode k Conducted susceptibility to transients on power leads 1 Radiated susceptibility to low frequency magnetic fields m Radiated susceptibility to RF electric fields n Susceptibility to electrostatic discharges 2 test results from subsystem and equipment level EMI tests shall be summarized Any specification non compliances judged to be acceptable shall be described in detail and the justifying rationale presented Electro Explosive Devices EED 1 appropriate requirements ECSS E 30 Part 6 and ECSS E 20 07 2 design techniques 3 verification EMC analysis 1 predictions of intra system EMI and EMC based on expected or actual equipment and subsystem EMI characteristics 2 design of solutions for predicted or actual interference situations Spacecraft level
72. n produce and verify a product to operate within its specified electromagnetic environment and performance characteristics It provides the instruction for conducting all activities related to the management the design requirements and the verification of the electromagnetic compatibility of all items of equipment and subsystems of a project A 2 Expected response A 2 1 Response identification The requirements for project identification contained in ECSS M 50 shall be applied to the EMC control plan A 2 2 Scope and content The EMC control plan shall provide the information presented in the following sections Introduction The EMC control plan shall contain a description of the purpose objective content and the reason of prompting its preparation 2 Applicable and reference documents The EMC control plan shall list the applicable and reference documents to support the generation of the document 78 DRAFT ECSS E 20B rev 1 17 April 2008 Terms and definitions abbreviated terms and symbols The EMC control plan shall include any additional definition abbreviation or symbol used 4 Requirements to be verified The EMC control plan shall list the EMC requirements to be verified covering at least the following areas a The programme management 1 responsibilities of customer and supplier at all levels lines and protocols of communication control of design changes planni
73. nal to the battery 3 overcharging 4 Attempt to charge in the case of primary cells 5 over discharge including cell reversal 6 cell leakage gases or electrolyte Where b above is not met the design shall mitigate the damaging effects of any such failure mode e g by containment of cell leakage at battery level 39 DRAFT ECSS E 20B rev 1 17 April 2008 The failure of one or more cells within a battery due to imbalance in the state of charge temperature or other parameter between cells should be prevented by the battery control electronics e When the battery has non insulated exposed cell terminals the battery should be delivered with a red insulation cover to be removed before satellite closure and for flight f Provision should be made not to change the thermal balance of the battery during charge and discharge operations with the cover notified in 5 6 5 2 e 5 7 Powerconditioning and control 5 7 1 Applicability The requirements in 5 7 2 and 5 7 3 apply to power subsystems those in 5 7 4 and 5 7 5 apply both to power subsystems and payloads and those in 5 7 6 apply to payloads 5 7 2 Spacecraft bus a No single point failure shall result in the loss of the power system capability to the extent that the minimum mission requirements in any of its phases cannot be fulfilled b For manned missions no double failure shall result in the loss of the power system capability to the exten
74. ng of the EMC control program facilities and personnel required for successful implementation of the EMC control program methods and procedures of accomplishing EMC design reviews and coordination programme schedules Integration of EMC program schedule and milestones within the program development master schedule b System level performance and design requirements l 29 099 SUM OS e p e 13 definition of electromagnetic and related environments definition of critical circuits allocation of design responses at system and subsystem and equipment levels antenna to antenna interference reduction analysis and technique magnetic moment upper limit required for AOCS magnetic cleanliness control plan spacecraft with specific payloads magnetic budget establishment of a controlled grounding scheme assessment of possible fault currents wiring including shielding and shield termination and categorization practises electrical bonding material properties effects of corrosion prevention and similar concerns on bonding and general EMC issues design criteria for alleviating effects of spacecraft charging and other electrification issues c Subsystem and equipment EMI performance requirements and verification l allocated EMI performance at the equipment level including tailored equipment level requirements The control plan shall be the vehicle for tailoring limits and test
75. nment moisture release in composites In all RF BFN structures having a central conductor ideally insulated the thermal power generated by Joule effect on the conductor itself shall be quantified and its impact on antenna performances assessed d For RF BEN l The applicable pressure range and gas properties shall be specified 2 The design and manufacturing shall be performed to avoid discharge phenomena according to Pashen curves valid for its specified pressure range and gas properties NOTE See section 7 3 for further details 7 2 2 3 5 Antenna RF chain a The circuit characteristics of the antenna RF chain shall be independently quantified and their impact on antenna performances assessed at least up to CDR b The cumulative effects of wave propagation discontinuities along the whole antenna RF chain including the radiating elements attached to it shall be quantified and the impact on antenna performances assessed For antenna RF chain l The applicable pressure range and gas properties shall be specified 2 The design and manufacturing shall be performed to avoid discharge phenomena according to Pashen curves valid for its specified pressure range and gas properties NOTE See section 7 3 for further details 7 2 2 3 Antenna support structures a The possible scattering effects of the support structures shall be quantified and their impact on the antenna performances assessed b Deviation
76. nt portions of the satellite platform shall be quantified ant their impact on antenna performance assessed NOTE For large array antennas that use hold down and release deployment mechanisms as well as pointing devices ECSS E 33 Part 11A can be applied 7 2 2 24 Amay fed reflectorantennas For array fed reflector antennas subclauses 7 2 2 2 2 Reflector Lens Antennas and Array Antennas shall apply 7 2 2 3 Hements 7 2 2 31 Radiating elements a The isolated performances of radiating elements shall be characterised as part of the performance prediction of the whole antenna at least up to the end of Phase B NOTE Individual radiating elements are a key element to the overall antenna performances They can be completed by a chain of RF components see antenna RF chain 7 2 2 3 5 to ensure a suitable RF interface b Whenever an antenna RF chain is attached to the Radiating Element its impact on the radiating element performances shall be assessed Deviations from the nominal geometry of the radiating element shall be quantified and their impact on antenna performances assessed NOTE Typical deviations are due to manufacturing errors thermo elastic effects and modification of the material characteristic in the orbit environment moisture release in composites d It shall be demonstrated that the scattering of the radiation pattern of individual radiating elements does not affect the accuracy of all radiated perfor
77. ntation and application of test procedures including modes of operation and monitoring points for each subsystem or equipment use of approved results from laboratory interference tests on subsystems and equipment methods and procedures for data readout and analysis means of verifying design adequacy of spacecraft electrification means of simulating and testing electro explosive subsystems and devices EEDs verifying electrical power quality and methods for monitoring DC and AC power busses test locations and descriptions of arrangements for simulating operational performance in cases where actual operation is impractical configuration of equipment and subsystems modes of operation to ensure victim equipment and subsystems are tested in most sensitive modes while culprit equipment and subsystems are tested in noisiest mode s details concerning frequency ranges channels and combinations to be specifically tested such as image frequencies intermediate frequencies local oscillator transmitter fundamental and harmonically related frequencies and including subsystem susceptibility frequencies identified during laboratory testing to precise parallel or series injection for conducted susceptibility test personnel to perform the test including customer and supplier personnel at all levels and quality representatives list of all test equipment to use including a description of unique EMC instrumentation for stimulating an
78. oD 3 5 6 4 SRR gt RoD 3 5 6 5 2 PDR gt A 3 5 6 5 2 PDR gt RoD A 3 5 6 5 2 c PDR RoD A 3 5 6 5 24 PDR RoD A 3 5 6 5 2 PDR gt RoD INS 1118117 5 6 5 2 PDR gt RoD A 3 5 7 2 PDR5 RoD A 2113 5 7 2 PDR5 RoD A 2115 5 7 2 0 1 2 amp 3 PDR5 RoD A 3 5 7 2 4 PDR5 RoD A 3 5 7 2 6 PDR gt RoD A 3 5 7 2 4 PDR gt RoD A 2113 5 72g PDR gt RoD 2113 5 7 2 h PDR A T 515 5 7 24 PDR gt RoD A T 3 5 5 7 24 PDR5 RoD 3 5 7 2 1 PDR gt A 3 5 7 2 k 2 PDR gt RoD A T 3 5 5 7 21 PDR gt RoD A T 3 5 5 7 2 m PDR5 RoD A T 15 5 7 2 PDR gt RoD A T 315 iic V a PDR gt RoD A T 3 5 6 5 7 2 PDR5 RoD A T 315 5 7 2 4 PDR5 RoD A T 315 5 7 9 1 PDR gt RoD A 3 5 1 3 8 PDR5 RoD A T 315 5 7 3 PDR5 RoD A 312 5 7 3 6 PDR gt RoD A 312 5 7 3 4 PDR5 RoD A 3 5 7 3 6 PDR RoD A 3 54 DRAFT ECSS E 20B rev 1 17 April 2008 5 7 3 3 5 7 3 8 PDR5 RoD A 3 5 7 3 h 3 5 7 83 3 5 7 4 RoD A T 3 5 5 7 4 b RoD A T 3 5 5 7 4 6 3 6 5 7 4 4 PDR gt RoD A 3 5 7 4 RoD A T 3 5 5 7 5
79. odulation products shall be agreed with the customer in the development phase b All the components of the RF chain shall be designed and manufactured to guarantee that the passive intermodulation products derived from the transmit carriers do not cause interference with any of the satellite receive bands or third party protected frequency bands during the operating temperature cycles 7 4 3 Identification of potentially critical intermodulation products operating conditions shall be identified in which two or more transmit RF signals simultaneously illuminate or passed through a passive RF component equipment or both For each of the conditions identified in 7 4 3 2 the frequencies number of carriers and power levels of these carriers shall be determined An analysis shall be performed to establish all the passive intermodulation products falling within any of the satellite receive bands or third party protected frequency bands for all combinations of frequency carriers up to the intermodulation order of 100 75 DRAFT ECSS E 20B rev 1 17 April 2008 5 7 4 4 Verification 1 Testing at the lowest intermodulation order as identified in 7 4 3 shall be performed to ensure that the amplitudes of the passive intermodulation products are below the specified interference level Passive Intermodulation tests shall be carried out on the flight hardware in the same configuration as it is during operational use
80. oints following verification methods SRR RoD 1 DDJ F PDR T 2 Tests Reports CDR A TRR INS TRB DRB NOTES FAR RoD includes review X Preliminary formal verification point ot documentation 7 3 2 1 a TRB INS 2 7 3 2 1 b TRB 2 7 3 2 1 2 7 3 2 2 PDR CDR TRB A T 1 2 7 3 3 1 1 PDR CDR TRB A T 1 2 7 3 3 1 2 PDR CDR TRB A T 1 2 7 3 3 1 3 PDR CDR TRB T 2 7 3 3 1 4 CDR TRB A T 1 2 7 3 3 1 1 SRR RoD 1 7 3 3 1 5 2 CDR RoD 1 7 3 3 2 PDR CDR TRR TRB A RoD T 1 2 7 3 4 INS 2 734b TRB T 2 742 SRR PDR CDR RoD 1 7 4 2 5 CDR A INS 1 7 4 3 PDR CDR TRR A RoD 1 2 7 4 3 PDR CDR TRR A RoD 1 2 743 c PDR CDR TRR A RoD 1 2 744a TRR TRB T 2 744b TRR TRB T 2 744 TRR TRB T 2 7 4 4 4 T 2 74 5 TRR TRB T 2 77 DRAFT ECSS E 20B rev 1 17 April 2008 Annex nomative control plan A l DRD identification 1 1 Requirement identific ation and source document ECSS E 20B subclause 6 2 2 A 1 2 Purpose and objective This Document Requirement Definition DRD establishes the data content requirements for the EMC control plan This DRD does not define format presentation or delivery requirements for the EMC control plan This DRD is applicable to all projects using the ECSS Standards The EMC control plan defines the approach methods procedures resources and organization to desig
81. oject C 2 Expected response C 2 1 Response identification The requirements for project identification contained in ECSS M 50 shall be applied to the Electromagnetic effect verification report EMEVR 2 2 Scope and content The EMEVR plan shall provide the information presented in the following sections Introduction The EMEVR shall contain a description of the purpose objective content and the reason of prompting its preparation 84 DRAFT ECSS E 20B rev 1 CSS 17 April 2008 2 Applicable and reference documents The EMEVR shall list the applicable and reference documents to support the generation of the document Terms and definitions abbreviated terms and symbols The EMEVR shall include any additional definition abbreviation or symbol used 4 Elements of the report The EMEVR shall include a identification of specific objectives including applicable requirements and EMEVP references description of test article e g configuration and drawings and photographs description of any fixes or configuration changes to article resulting from verification failures description of changes to cables attached to the equipment under test with respect to the EMEVP summary of results including an executive summary stating degree of conformance to requirements description of any deviations from test facilities analysis techniques or tools and inspection aids in EMEVP
82. orm the necessary work This allows existing organizational structures and methods to be applied where they are effective and for the structures and methods to evolve as necessary without rewriting the standards This Standard has been prepared by the ECSS Electrical and electronic Standards Working Group reviewed by the ECSS Executive Secretariat and approved by the Technical Authority DRAFT ECSS E 20B rev 1 17 April 2008 Contents 15 2 Nomative references 3 Tems definitions and abbreviated terms 3 1 Termsand definitions 3 2 Abbreviated terms 4 General requirements 41 Interface requirements 4 1 1 Overview 4 1 2 Signals interfaces 4 1 3 Commands 4 1 4 Telemetry 4 2 Design 1 Failure containment and redundancy 2 Data processing 3 Electrical connectors 4 Testing 5 Mechanical 6 Dependability 4 3 Preparation fordelivery 4 4 Verification 4 4 1 Provisions 4 4 2 Documentation 5 Electrical power 5 1 Functional description 5 2 Powerand budgets 5 2 1 Overview 5 2 2 Provisions 5 3 Failure containment and redundancy 5 4 Electrical powerinterfaces 5 5 Energy generation 5 5 1 Solar cell coverglass SCA and PVA requirements 5 5 2 Solar array specification and design 28 28 28 28 29 30 30 30 30 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 3 Solar array power computation 5 5 4 Solar array drive mechanisms 5 6 Electrochemical Energy Storage 5 6 1 Applicability
83. ormal verification point documentation 5 Tests Reports 6 Specification 7 User manual 5 2 1 PDR RoD 2 5 2 2 1 SRR RoD A T 3151 5 2 2 2 PDR RoD A 2 3 5 2 2 2 PDR RoD A 2 3 5 2 2 2 PDR RoD 2 5 2 2 2 d PDR RoD 3 5 2 2 2 6 PDR FAR RoD A 2 5 2 2 24 PDR RoD A 2 3 5 3 8 PDR RoD 3 5 3 PDR RoD A 3 5 3 6 PDR RoD A 3 5 8 4 PDR RoD A 3 5 4 8 1 amp 2 SRR5 RoD 11416 5 4 PDR RoD 1 41 6 5 4 FAR A T 3151 5 4 d PDR RoD 1114116 5 4 PDR A 3 5 5 2 8 PDR A 2 5 5 2 b PDR A 3 5 5 2 PDR RoD A T 3 5 5 5 2 d PDR RoD A 3 5 5 2 6 1 3 5 5 2 2 T 5 5 5 241 2 amp 3 RoD A T 3 5 5 5 2 g RoD A 3 52 DRAFT ECSS E 20B rev 1 17 April 2008 5 5 2 h 3 5 5 9 1 3 5 5 2 1 3 5 5 2 2 T 5 5 5 2 k RoD A 3 5 5 2 3 5 5 2 m RoD A T 3 5 5
84. ormal transients including interdomain are within 5 all included Abnormal transients are more than twice the normal transients the load is then designed to operate nominally in normal transients and sustain without damage abnormal transients 41 DRAFT ECSS E 20B rev 1 17 April 2008 5 1 In case of fuse blowing the recovery from the fuse clearance shall not produce an overshoot of more than 10 above the nominal bus value 2 The model of the fuse and of the electrical network to be protected by the fuse shall be validated by test with a representative set up A fully regulated bus shall have a nominal ripple voltage below 0 596 peak to peak of the nominal bus voltage Measured at the regulation point with at least 1 MHz bandwidth m A fully regulated bus shall have commutation voltage spikes in the time domain of less than 2 peak to peak of the nominal bus voltage Measured at the regulation point with an analogue oscilloscope of 50 MHz minimum bandwidth or a digital oscilloscope offering equal or better performance n At the point of regulation the impedance mask of a fully regulated bus operating with one source e g battery solar array shall be below the impedance mask shown in Figure 1 NOTE Rationale for the impedance mask It translates requirement 5 7 2 1 1 of 1 voltage change for 50 load change in a domain of regulation up to 10 kHz bandwidth In DC the integrator in the control loop
85. ound With the exception of the solar array power lines shall be such that each line is twisted with its return when the structure is not used as a return NOTE The purpose of the requirements b and c is to minimize current loop area and harness inductance d The power distribution shall be protected in such a way that no over current in a distribution wire can propagate a thermal failure to another wire e The harness inductance for a fully regulated bus from the distribution node of the regulated bus to the load shall be such that the break frequency is at least 5 000 Hz NOTE That means that L R 2nf where L harness inductance in H R harness resistance in 2 f break frequency in Hz i e f 5 000 NOTE Rationale for this requirement This ties up with the impedance mask requirement because beyond the break frequency the impedance is going to rise and one wants to keep the quality established on the regulation point with the impedance mask as best as possible and as far as possible to the loads f Harness shall be tested up to connector brackets under 500V DC between conductors conductors and structure conductors and shielding NOTE 500V DC is selected in order to detect insulation defects potentially induced by air voltage breakdown g The harness restraining systems on the structure shall not bring about any stress at connector level 49 DRAFT ECSS E 20B rev 1 17 April 2008 5
86. part of the EMC Programme an EMC Control Plan shall be written by the supplier for the PDR including the DRD in Annex A NOTE The Control Plan initial release documents the procedures of the EMC Programme including basic design guidelines while subsequent routine updates document the programme progress b The EMC control plan shall apply to every item of equipment and subsystem in the project 6 2 3 Electromagnetic compatibility advisory board EMCAB a For such programmes where EMC has been identified during phase A as critical for mission performance the EMC programme shall include an EMC Advisory Board EMCAB b The EMCAB shall 1 Ensure the timely and effective execution of the programme under the general project manager 2 Respond to the problems related to EMC as they arise The supplier shall chair the EMCAB with customer oversight NOTE The EMCAB members are representatives of the Spacecraft Supplier and payload suppliers and users NOTE EMCAB members can invite associate contractors or independent experts NOTE The EMCAB accomplishes its duties and document its activities mainly through the use of the system level EMC documentation 58 DRAFT ECSS E 20B rev 1 17 April 2008 5 6 3 System level 6 3 1 Electromagnetic interference safety margin EMISM 6 3 1 1 Circuits categories Functional criticality of circuits for all equipment subsystem circuits shall be identified in acco
87. r equipment of the same part number and of the same qualification status b The uniformity of the performance characteristics and dimensions of the units shall enable equipment interchange without unforeseen adjustments and recalibration When components operating in a single event e g fuses are used 4 times the quantity to be used for flight units shall be procured as one lot 25 for the lot acceptance test 25 for flight use 25 for spares and 25 for a confirmation test near to the launch date d The number of components to be procured shall be defined to ensure as a minimum the quantity needed for flight and flight spares plus the number of components to be tested at incoming reception and components to be tested just before launch in case of alert or failure 43 Preparation fordelivery For packaging marking and labelling see ECSS Q 20B Clause 10 4 44 Verification 4 4 1 Provisions The requirements of this Clause 4 shall be verified by the verification methods at the reviews and recorded in the documentation as specified in Table 4 1 NOTE For verification see also ECSS E 10 02 4 4 2 Documentation a The DDJF contains all descriptions and analyses meant to verify that the design meets the requirements It shall cover in particular design report PSA WCA FMECA thermal Analysis Radiation Analysis EMC analysis supported by the detailed circuit diagrams b Failure modes of all components used
88. ransmitter is routed to the radiating elements in a receiving antenna the RF power coming from the radiating elements is routed to the antenna ports connected to the receiver 3 1 8 conducted emission CE desired or undesired electromagnetic energy that is propagated along a conductor 3 1 9 diffusivity the ability of a body to generate incoherent diffuse scattering due to local roughness inhomogeneity or anysotropy when illuminated by RF waves 3 1 10 depth of discharge DOD ampere hour removed from an initially fully charged battery expressed as a percentage of the nominal nameplate capacity 3 1 11 double insulation barrier between conductors or elements of an electronic circuit such that after any credible single failure conductors or elements of an electronic circuit are still insulated from each other 3 1 12 electrical bonding the process of connecting conductive parts to each other so that a low impedance path is established for grounding and shielding purposes 3 1 13 electromagnetic compatibility EMC ability of equipment or a system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment 3 1 14 electromagnetic compatibility control set of techniques to effectively regulate the electromagnetic interference environment or susceptibility of individual space system components or both 10 DRAFT ECSS E 20B
89. rdance with the following categories Critical circuits category I Safety Critical EMI problems that can result in loss of life or loss of space platform This category comprises electro explosive devices and their circuits Critical circuits category II Mission Critical EMI problems that can results in injury damage to space platform mission abort or delay or performance degradation which unacceptably reduces mission effectiveness Critical circuits category 111 Non critical Any problems that do not belong to categories a and b 6 3 1 2 Critical points The list of points where the margin is demonstrated critical points shall be submitted to the customer for approval 6 3 1 3 Margins a Electromagnetic interference safety margins shall be determined at critical points under all operating conditions b The minimum safety margins shall be 20 dB for category I circuits and 6 dB for category II circuits 6 3 2 Inter system EMC and EMC with environment 6 3 2 1 Overview The objectives of the following requirements are to ensure that the space system operates without performance degradation in the electromagnetic environment due to external sources natural sources and man made sources intentional or not 59 DRAFT ECSS E 20B 1 CSS 17 April 2008 6 3 22 with the launch system The electromagnetic environment seen by the spacecraft and the EMC requirements during the pre launch and laun
90. regulators and the unit case shall be less than 50 nF per converter NOTE Rationale for this requirement The value of 50 nF is a compromise such that for a given piece of equipment this value is sufficiently high to dominate all parasitic capacitances to unit case and low enough such that 1f many equipments are connected to a bus the sum of bypassing capacitors to unit case and thus to ground reference is not significantly biasing the insulation of the bus or bus return to ground e If a switching converter 15 externally synchronized it shall remain in nominal operation for any increase or decrease of synchronizing frequency intermediate amplitude of synchronizing signal phase jumps or loss and recovery of the signal l An analysis at unit level shall be performed to verify that no single failure generates an increase of conducted emission exceeding specified limit by more than 6db 2 If an increase of conducted emission exceeding specified limit by more than 6db is identified from the unit level analysis then a system level analysis shall be conducted to ensure that compatibility is maintained NOTE Rationale for this requirement 6 dB is the margin usually taken between unit and subsystem when building up the EMC compatibility at system level It means that failed equipment uses that EMC margin but does not perturb further the system g A switching converter shall be able to reach nominal operation when the nominal inpu
91. rmance aspects in case of e g load transients or start up of a load downstream with other loads already connected on a common path upstream must result in an overall stable situation Source Block Load Block e4 hiems H e E EE SL F 24 V V 2 W 1A B hoy B 1 e 7 B ow Ls cad Figure 2 Source Block cascaded with a Load Block The term 1 H represents the loading effect caused by integrating the subsystems H can be viewed as the system equivalent loop gain and the integrated system stability can be determined by applying the Nyquist criterion to Hm non protected sections of main bus distribution system shall be protected as a minimum by double insulation including harness connector wiring and PCB up to the first protection device fuse current breaker or current limiter d All load paths shall include protection circuitry on the source side NOTE The aim is to locate them as near as possible to the source e No load shall be permanently disconnected from its power source as a consequence of an SEE f If fuses are used to protect main bus distribution lines they shall be accessible and replaceable without compromising equipment acceptance up to and including the final integration of the stand alone spacecraft 47 DRAFT ECSS E 20B rev 1 17 April 2008 55 Switching ON OFF load supplied from
92. ry main frame period after onset of the discharge or 2 within some other period defined by the customer g A command to the space vehicle from an external source such as a ground station need not be executed if an arc discharge occurs during transmission of the command h Provision shall be made such that 1 unintended action does not result 2 the space vehicle is capable of receiving and executing subsequent commands and 3 the space vehicle meets specified performances within the time period defined in subclause a 6 3 5 Intrasystem The space system shall operate without performance degradation in the electromagnetic environment due to on board sources intentional or not 6 3 6 Radio Frequency Compatibility 1 The spacecraft shall be RF compatible with all antenna connected equipments and subsystems the compatibility criteria being based on the mission performance and operability requirements When an inter system interface is required each system shall be compatible with all antenna connected equipments and subsystems the compatibility criteria being based on the mission performance and operability requirements k The RF compatibility analysis if used instead of test shall include the effects of inter modulation products 6 3 7 Spacecraft DC magnetic field emission 6 3 7 4 Overview DC magnetic emissions have impacts on two main areas magnetic sensors of payloads and the attitude con
93. s from the nominal geometry of the supporting structure shall be quantified and their impact on antenna performances assessed NOTE Typical deviations are due to manufacturing errors thermo elastic effects and modification of the material characteristic in the orbit environment moisture release in composites 7 2 2 4 Technologies 7 2 2 4 1 Metal based a The level of passive inter modulation products generated by the antenna shall be quantified and their impact on antenna performances assessed See section 7 4 for further details NOTE Ferro magnetic materials and metal to metal junctions are the most common non linear elements in antennas b The impact of thermally induced effects the generation of passive intermodulation products shall be quantified and the impact on antenna performances assessed 69 DRAFT ECSS E 20B rev 1 17 April 2008 5 typical example of thermally induced effects triggering the generation of PIM is the sudden releases of stresses in metal to metal joints due to temperature variations Thermally induced changes of dimension and shape in all metallic antenna parts shall be quantified and their impact on antenna performances assessed 7 2 2 4 2 Composite based a The impact of surface characteristics and finish on antenna performances shall be assessed NOTE In particular this 1s essential for the RF conductive surfaces of the component NOTE Electrical conduc
94. se 5 6 5 defines additional safety requirements for all battery types Fuel cells and super capacitors are not addressed by the present standard 5 6 2 Batteries a Batteries shall be designed to support the spacecraft through the launch sequence including all anticipated contingencies and through all foreseen losses of solar energy during the mission including those resulting from failures e g depointing due to loss of pointing sensors attitude control b The ability of a battery to meet mission lifetime requirements specified by the spacecraft manufacturer in the battery specification where not covered by qualification life testing or previous in flight experience shall be justified by the ground test data or by dedicated tests under representative conditions 1 Specific measures shall be taken in the battery design to keep under control the series inductance and the magnetic moment 2 In case verification by analysis is not conclusive a complementary verification by test shall be performed d Batteries having to tolerate a single fault shall be designed such that they can operate with one cell either failed shorted or open circuit 35 DRAFT ECSS E 20B rev 1 17 April 2008 In batteries having to tolerate a single fault and where the effects of single cell failure are mitigated by the use of a cell bypass device then l The probability of the bypass circuit untimely operation shall be lower th
95. sions shall be made for recovery from lock up The solar array design shall satisfy the power requirements established by the spacecraft manufacturer in the solar array specification for each mission phase in worst case conditions d Provision shall be made against potential failure propagation in case of short circuit failure of a solar array section and its connection to the power system 30 DRAFT ECSS E 20B rev 1 17 April 2008 5 1 The solar array design shall be such that charging phenomena do not degrade the performance of the solar array below the requirements specified in a and c NOTE Good practices in accordance with the present state of the art are to limit the differential voltage in between cells to 30V in all conditions if the minimum accepted gap between adjacent non directly connected cells is 0 5mm to implement string blocking diodes to have a coverglass extending beyond the solar cell limits 2 In case verification by analysis 15 not conclusive a complementary verification by test shall be performed f In the flight configuration the following shall be applied l Avoid electrical continuity of the solar array conductive panels to each other or to the spacecraft structure 2 Implement means to prevent differential voltage due to electrostatic charging between solar array structure and the satellite electrical ground reference 3 Implement bleeding resistors NOTE
96. t 21 DRAFT ECSS E 20B rev 1 17 April 2008 sAcss 6 It shall be ensured that erroneous mating is avoided by connector keying or marking NOTE The requirement is met either by harness routing or by using keyed connectors or adequate positioning of connectors or connectors of different type or size or connector marking f If the equipment has several connectors visibility and clearance around each of them shall be such as to enable mating or de mating without disturbing others already in place or necessitating custom made tooling NOTE A usual practice is the insertion of a breakout box for trouble shooting g For supplies and signals of pyrotechnics and non explosive single shot device drivers 1 Different connectors should be used for different classes of electrical functions 2 When 1 above is not met power signals and telemetry shall be separated in the connector by a set of unused pin locations h Spare contacts or sockets shall be available on each connector 1 For new developments when connection is not aligned to a defined standard 1096 spare contacts at unit and at least 5 at shall be achieved with in any case a minimum of two spare contacts available at CDR In the absence of grounding provision at connector shell level at least one contact per connector shall be connected to the unit structure as provision for potential additional grounding at subsystem or system l
97. t that the minimum mission requirements in any of its phases cannot be fulfilled The following main control features of a power bus shall be completely independent from any control external to the electrical power system even in case of failure 1 Main Bus voltage regulation control for regulated Bus 2 Battery discharge control 3 Control of solar array power when using Maximum Power Point Trackers MPPT NOTE Main control features do not include parameter settings by the OBC d The ultimate switching between main and redundant MPPT circuitry shall be implemented by hardware independent from any on board software 40 DRAFT ECSS E 20B rev 1 17 April 2008 5 No single point failure in the spacecraft including for instance failure of wiring and connectors shall open or short a main electrical power bus or violate the specified over voltage or under voltage limit requirements f The design shall ensure that under all conditions during the required lifetime including operation in eclipse with one battery cell failure and one solar array string failed the main bus voltage remains within nominal tolerances g For fully regulated buses the nominal bus voltage value should be standardized according to the following 1 28 V power up to 1 5 kW 2 50 V for power up to 8 kW 3 100 V and 120 V for higher power NOTE Bus voltage types are standardized in order to maximize the reuse of equipments
98. t voltage is applied with any slope that can be provided by the power source and its associated impedance connected to the switching converter 5 7 6 Payload interaction a Inrush under voltage and a representative set of failures agreed with the customer for the payload interaction with the main bus shall be verified by test b No load shall generate a spurious response that can damage itself or any other equipment during bus voltage variation up or down at any ramp rate and over the full range from zero to maximum bus voltage l 1 current limiting devices and automatic switch off circuits shall be monitored by telemetry 2 2 The failure of the monitoring function shall not cause the protection elements to fail 46 DRAFT ECSS E 20B rev 1 17 April 2008 055 5 8 Powerdistribution and protection 5 8 1 General a The primary power source shall be grounded to the spacecraft structure at the star reference point with a connection capable of sustaining the worst case fault current b Whenever two or more blocks are connected in cascade the stability of the cascade between each source block and load block shall be ensured by 1 meeting the Nyquist criterion or 2 demonstrating that ZSource ZLoad by one decade NOTE Rationale for this requirement This requirement comes from lessons learnt on complex cascaded distribution systems where beyond selective hierarchical protection aspects also perfo
99. the minimum value shall be at least 50 ms NOTE Rationale for the requirement The bus overload can be due to a failure of a load Disconnecting prematurely or attempting to disconnect prematurely this load can damage the relay in the presence of a high fusing current Fuses blow within 20ms see requirement 5 8 1 1 thus leaving 50 ms allows the fuse clearance which can restore the bus to its nominal value without performing a non essential load shedding b In the case of an unregulated bus or battery supply all non essential loads shall be switched off automatically in the event of reaching the battery energy level that is able to maintain all essential loads for a time guaranteeing safe recovery 44 DRAFT ECSS E 20B rev 1 17 April 2008 5 The ultimate non essential load disconnection circuit Ds shall be implemented as a full hard wired chain from sensor to actuator 2 shall be one failure tolerant d The spacecraft design shall be such that in the event of an under voltage condition on the bus no failure is induced in the power system or the loads during and when recovering from this under voltage e After recovery as mentioned in d l all essential loads shall be supplied nominally 2 all non essential loads shall be in a known configuration that cannot create damage to any part of the spacecraft 5 7 5 Powerconverters and regulators a For converters and regulators of the power system solar arr
100. tivity and depolarisation properties are the most typical parameters affected b Thermally induced changes of dimension and shape in all composite and combined metal composite antenna parts shall be quantified and their impact on antenna performances assessed Measures to drain accumulated electric charges from composite parts shall be implemented to avoid Electrostatic Discharge ESD 7 2 2 4 3 Plastic based a The dielectric losses of plastic component in the RF power path shall be quantified and their impact on antenna performances assessed NOTE Components made from homogeneous plastic are usually limited to small parts e g spacers or washers b Thermally induced changes of dimension and shape in all plastic and combined metal plastic antenna parts shall be quantified and their impact on antenna performances assessed Measures to drain accumulated electric charges from all plastic parts shall be implemented to avoid Electrostatic Discharge ESD 7 2 2 5 Performance parameters The characterisation of antenna performances shall cover the following parameters Coverage or Beam shape Directivity Electrical boresight or Beam pointing Gain or Beam efficiency Input impedance mismatch factor Radiation pattern Sense of polarization Side lobe level Polarisation purity or Axial ratio Group delay Noise temperature for receive antennas Phase centre position 70 DRAFT
101. trol system ACS Other specific 61 DRAFT ECSS E 20B rev 1 17 April 2008 components are susceptible ultra stable crystal oscillators plasma monitors high permeability magnetic shields 6 3 7 2 Spacecraft with susceptible payload In case the payload involves equipments sensitive to DC H Field the maximum acceptable DC magnetic field at their location from the rest of the spacecraft shall be specified by the customer because of the mission performance requirements NOTE Itis the role of the EMCAB to translate the customer s DC magnetic field requirements specified at the sensitive payload location into subsystem and equipment magnetic requirements magnetic field or magnetic moment limits test methods 6 3 7 3 Attitude control subsystem On the basis of the attitude control requirements the supplier shall derive magnetic requirements for the spacecraft so as to limit transient diurnal and secular torques m If magnetometers are used as part of the Spacecraft Attitude Control Subsystem the maximum acceptable DC magnetic field at their location from the rest of the spacecraft shall be specified by the supplier because of the Attitude Control Subsystem requirements and submitted to the customer approval 6 3 8 Design provisions for EMC control 6 3 8 1 Electrical bonding Detailed requirements are specified in ECSS E20 07 clause 42 11 Electrical bonding requirements 6 3 8 Grounding A controlled
102. y regulated bus Bus providing power during sunlight and eclipse periods with a regulated voltage 3 1 21 grounding The process of establishing intentional electrical conductive paths between an electrical circuit reference or a conductive part and equipment chassis or space vehicle structure NOTE grounding is typically performed for safety functionality signal integrity EMI control or charge bleeding purpose 11 DRAFT ECSS E 20B rev 1 17 April 2008 5 3 1 22 high Priority telecommand HPC Command originated from ground and issued by the telecommand decoder for essential spacecraft functions without main on board software intervention 3 1 23 high voltage AC or DC voltage at which partial discharges corona arcing or high electrical fields can occur 3 1 24 lens antenna a lens antenna is defined as an antenna composed by a number of RF lenses and reflecting surfaces illuminated by a primary source the feed 3 1 25 latching current limiter LCL latching current limiting function used for power distribution switching and protection 3 1 26 lightning indirect effects electrical transients induced by lightning in electrical circuits due to coupling of electromagnetic fields 3 1 27 major reconfiguration function function used to recover from system failures of criticality 1 2 or 3 as defined in table 1 of the ECSS Q30 C and ECSS Q 40 C 3 1 28 nominal nameplate capacity capacity state

33Draft ECSS-M-00-03A

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