STK / SEET R
Contents
1. STK SEET RADIATION ENVIRONMENT TUTORIAL Contents MITE V0 aie pacercea ret E E em een xe na eae ee 1 Problemi Statement rire aa re Ta a TRAE E E T ET ee en eer 1 G tting Started eseina e E R E EN EE EE EE E E 1 Sol tion APT OAC cs ccsessisvnsscasstssbaxeseeissensiiiexetoosnumeboesuem MeaWecesnsuvetondsumbsvestendembaasudees 2 Create the UNA css csetasascicvateipacact ng T R 2 Configure the SEP Environment to use the ESP model ssssssessesseeesessseesessesssesee 2 Create a report to list the probability of exceeding a given fluence as a function of threshold ENErg Yireiieieeso icenian RE a EEE EE EE aE EEEE 2 Licenses Needed This tutorial requires that you be licensed for the STK Space Environmental Effects Tool SEET Introduction The SEET SEP component provides a suite of models for computing cumulative solar energetic particle fluences near Earth The models provided include JPL 91 Rosenqvist and ESP Rosenqvist is essentially an update of JPL 91 ESP uses a different modeling approach and is based on a somewhat different data set All three models calculate the probability of exceeding a given fluence above a given threshold energy in free space outside the Earth s magnetosphere no geomagnetic cutoff effects are currently applied Therefore SEET output for SEPs currently consists only of reports and graphs and no 2D or 3D graphics In addition the model outputs are strictly applicable mainly to geosyn chronou2. atellite is selected In the Styles pane click on the Create New Report Style icon An icon called New Report will appear under My Styles give it a name like SEP Fluence Right click on the icon and se lect Properties Under the Data Providers pane scroll down to the SEET SEP Model select that entry and click the right arrow to add SEET SEP Model Def inition to the Report Contents pane Then click on SEET SEP Fluence by Probability per Energy and click the right arrow to send the Log Probability and Log Fluence parameters to the Report Contents Then click OK to close the box 6 Click again on the report icon you just created and then click on Generate A report box will be generated containing the following A Definition section giving the SEP model and the threshold energies A number of sub sections for energy listing Fluence and Probability You can easily navigate the report by clicking in the Jump To box at the top and clicking on the energy level you re interested in 7 Repeat Steps 5 and 6 to produce a Graph Notes use the New Graph icon in the Report amp Graph Manager in the Graph Properties dialog be sure to select Graph Type XY at the top before proceeding you may wish to go back to the Satellite Properties dialog and remove some energies from the SEET SEP ESP energy list in order to keep the graph from being cluttered Note Th
3. ds Click OK and save the new scenario Next add a satellite to the scenario We will use a nominal geosynchronous orbit since the GCR models apply here with no geomagnetic shielding Select menu nsert New Under Scenario Objects highlight Satellite Un der Select a Method choose Orbit Wizard then click on Insert to bring up the Orbit Wizard In the Orbit Wizard window for Type select Geosynchro nous and give the satellite a name like GEO1 Then in the Definition panel set the Subsatellite Point to 120 degrees Make sure the Inclination is set to 0 deg Then click OK Close the Insert STK Objects dialog box Configure the SEP Environment to use the ESP model 4 Next we will configure the SEET SEP environment for the ESP model On the Satellite Properties page under Basic select SEET SEP In the Model box select ESP The default list of energies is given in MeV the Remove button can be used to restrict the list to just those energies Reset to Defaults restores the original list Ignore the Report Probability box for now Click OK Create a report to list the probability of exceeding a given fluence as a function of threshold energy 5 To compute and view the output for this model bring up the Report and Graph Manger by selecting Analysis Report amp Graph Manager from the main menu Make sure Object Type S
4. e reports and graphs above are all available as default styles in the standard STK SEET install with the following names SEET SEP Fluence by Probability per Energy report and graph and SEET SEP Fluence by Energy per Probability to Exceed re port and graph
5. s altitudes and above the output represents a maximal estimate for other orbits See the SEET User Manual for further information Problem Statement For a given space vehicle configuration and orbit determine the probability of exceeding a given fluence for a given mission duration Getting Started The primary decision to make when developing an SEP scenario using STK involves se lecting which model to use Here we will use the ESP model Inputs for JPL 91 and Rosenqvist are essentially identical they differ only in the list of threshold energies available Solution Approach Build a scenario that will cover the desired time period for the satellite orbit of interest Set the relevant model parameters to achieve the desired results Configure STK proper ties as needed to obtain the desired reports and graphs Create the Scenario l 2 3 Create a new scenario by using the New Scenario Wizard by selecting New from the File menu or by clicking the corresponding toolbar button amp Fill in the scenario name and description Right click on the scenario and select Properties to open the scenario settings For the analysis period enter 22 Feb 1975 00 00 00 000 UTCG to22 Feb 1986 00 00 00 000 UTCG In the Animation panel select the check box next to Stop at Time and the check box next to Use Analysis Stop Time this stops the animation at the selected stop time Set the Step Size to 300 secon
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