FRR-16SolarSystem.docx
Solar System
Lead: SPH
Developer: WCS
Tester: JMB
Behavior When Changing the Coordinate System
Explore
This section is to document an initial list all known issues with this feature. Put findings here during feature exploration. This is a temporary holding place, and all of these items MUST be moved to JIRA early in the feature finalization or they will not be tracked or scheduled to be fixed!
Known Bugs
Known bugs committed in JIRA against this feature.
P1 R2013a
Bug GMT-3135
User-provided SPK kernel is not validated or used
Bug GMT-1304
Setting SPK kernel name in GUI overwrites DE file name
Bug GMT-3134
DEFileName field contains stale data after invalid file is rejected.
Bug GMT-3131
Invalide warning thrown when loading SPK kernel for most built-in bodies
P2 R2103a
Bug GMT-3132
Crash when invalid DE file is specified
Bug GMT-2725
User cannot clone, rename or delete User-defined bodies (ie. a new moon or comet)
Wendy Shoan R2013a P2 Open Open Unresolved
Actions
Bug GMT-3103
Double error window for Solar System objects when entering invalid value in panel
Steven Hughes Someday P3 Open Open Unresolved
Actions
P3 Someday/Enhancement
Bug GMT-2336
Error Propagating Earth Using Two Body Model
Wendy Shoan Someday P3 Open Open Unresolved
Actions
Bug GMT-2323
Errors in TwoBody Computations for User-Defined Bodies
Wendy Shoan Someday P3 Open Open Unresolved
Actions
Bug GMT-348
Need .jpg files for Comet and Asteroid
Linda Jun Someday P3 Open Open Unresolved
Actions
Bug GMT-2178
Solar System: extra blank line was added to default planet's scripts
Wendy Shoan Someday P3 Open Open Unresolved
Actions
Bug GMT-2216
LSK file text ctrl remains visible when source set to DE405 or 2Body
Wendy Shoan Someday P3 Open Open Unresolved
Actions
Failing Tests
Other Findings/To Do
● Remove old warning message for outer planets when using SPK for Ephem Source.
● Remove old SPK file from data files
If you provide a non-existent file in the GUI, you get a string of error messages like this. This error message is old dating back to when EphemerisSource was a list. We should fix the message. In addition, the mission runs but I have no idea what ephem is used.
Error opening DE file:../data/planetary_ephem/de/leDE1900.405.
Please check file path. The next filetype in the list will be used.
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ID |
Requirements |
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FRR-xyz |
The requirement. |
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FRR-xyz. |
The requirement |
Interface/Functional Spec
Overview
High level solar system configuration options.
Description
The SolarSystem resource allows you to define global properties for the model of the solar system including the ephemeris source for built-in celestial bodies and selected settings to improve performance when medium fidelity modelling is acceptable for your application.
See Also : Celestial Body, LIbration Point, Barycenter, CoordinateSystem.
Fields
See the User Interface Spec spreadsheet for reference information for fields.
GUI
The SolarSystem dialog box allows you to configure global properties for solar system modelling and the default configuration is illustrated above. Use EphemerisSource to choose the ephemeris model for built-in celestial bodies. If you select either DE405, DE421, or DE424 the dialog box above illustrates available options.
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Caution: GMAT allows you to provide user-created DE or SPK kernel files but we recommend using the files distributed with GMAT. The files provided with GMAT have been extensively tested for consistency and accuracy with the original data provided by JPL and other models in GMAT. Using inconsistent ephemeris files or user-generated files can result in instability or numerical issues if the files are not generated correctly.
Changing the ephemeris source for an application is equivalent to making a fundamental change to the model of the solar system. We recommend selecting the EphemerisSource early in the design process and using that model consistently. In the event that an ephemeris model change is necessary, we recommend that you change the model in the script file and not via the GUI. We allow you to change EphemerisSource via the GUI for convenience in early design phases when rigorous consistency in modelling is less important. |
If you select SPICE for EphemerisSource, the SolarSystem dialog box reconfigures to allow you to define the SPK Kernel and the leap second kernel.
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For Developer/GUI Tester: The SolarSystem dialog box configuration is different depending upon the selection of EphemerisSource. If EphemerisSource is SPICE the GUI label should read “SPK Kernel” and the Leap Second Kernel field and browser button should be displayed. If Ephemeris Source is DE405, DE421, or DE424, then the GUI label for the file field should read “DE Filename” and the Leap Second Kernel fields should NOT be displayed. |
Remarks
GMAT uses the ephemeris file selected in the EphemerisSource field for all built-in celestial bodies. For user-defined bodies, the ephemeris model is specified on the CelestialBody object.
● For more information on the DE files provide by JPL see the readme file here( http://iau-comm4.jpl.nasa.gov/README).
● For general information on SPICE ephemeris files see http://naif.jpl.nasa.gov/naif/toolkit.html
● For information on the SPK kernel named DE421AllPlanets.bsp distributed with GMAT see the SPK.README located in data\planetary_ephem\spk in the GMAT distribution.
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Note: The SolarSystem and built-in CelestialBody resources require several hundred fields for full configuration. GMAT only saves non-default values for SolarSystem and CelestialBody to the script so that scripts are not populated with hundreds of default settings. |
Examples
Use DE421 for Ephemeris.
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GMAT SolarSystem.EphemerisSource = 'DE421';
Create Spacecraft aSpacecraft; Create Propagator aPropagator; aPropagator.FM = aForceModel; Create ForceModel aForceModel aForceModel.PointMasses = {Luna, Sun};
BeginMissionSequence;
Propagate aPropagator(aSpacecraft) {aSpacecraft.ElapsedSecs = 12000.0}; |
Use SPICE for Ephemeris.
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GMAT SolarSystem.EphemerisSource = 'SPICE';
Create Spacecraft aSpacecraft; Create Propagator aPropagator; aPropagator.FM = aForceModel; Create ForceModel aForceModel aForceModel.PointMasses = {Luna, Sun};
BeginMissionSequence;
Propagate aPropagator(aSpacecraft) {aSpacecraft.ElapsedSecs = 12000.0}; |
Test Procedures
Assumptions
If you are making assumptions about how tests will be performed or that other test areas will cover some of this functionality describe that here.
SolarSystem EphemerisUpdateInterval
SolarSystem UseTTForEphemeris
SolarSystem EphemerisSource
SolarSystem DEFilename
SolarSystem LSKFilename
SolarSystem SPKFilename
Existing Tests
Describe existing test types using a row for each class of test.
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Priority |
Status |
Summary |
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P1 |
Done:SPH |
Test using SPK, DE421, DE405, and DE424 in coordinate system translations
See files named EphemTest_SPK_* EphemTest_DE405_* EphemTest_DE421_* EphemTest_DE424_*
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P1 |
Done:SPH |
Test using SPK, DE421, DE405, and DE424 in propagation:
See files named: GMAT_LunarTransfer_AllPlanets_DE405 GMAT_LunarTransfer_AllPlanets_DE421 GMAT_LunarTransfer_AllPlanets_DE424 GMAT_LunarTransfer_AllPlanets_SPK |
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P1 |
Done: SPH |
Test using TT in ephemeris by setting UseTTforEphemers to true:
See file named below located in Dynamics Model test folder GMAT_LunarTransfer_UseTTForEphemIsTrue
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P1 |
Done: SPH |
Test Ephem sources in barycenter and libration point: See files named like below located in Barycenter and Libration test folders:
Barycenter_*_PlutoOrbit LibPoint_Earth_Luna_EarthOrbit_L2_* |
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P1 |
Done: SPH |
Test ephemeris update interval at zero and non zero values. See files named: SolarSystem_EphemUpdateInterval_* |
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P1 |
Done:SPH |
Test providing user defined SPK kernel for main solar system ephemeris |
Recommended Additional Tests
Nominal Tests
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Priority |
Status |
Summary |
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P2 |
Deferred |
Test spk leap second kernel calculation by computing ephemeris before and after addition of leap second with truth data.
Numerous indirect numerical tests verify this works and there is currently no direct way to test. If the file was not loading, SPK ephem source could not work. -SPH |
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Edge/Corner/Stress
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Priority |
Status |
Summary |
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P1 |
Done: SPH |
Test that errors are thrown when propagating off DE405, DE421, DE405 and SPK files.
See files named: PropOffEphem_Backward_DE405 PropOffEphem_Backward_DE421 PropOffEphem_Backward_DE424 PropOffEphem_Backward_SPK PropOffEphem_Forward_DE405 PropOffEphem_Forward_DE421 PropOffEphem_Forward_DE424 PropOffEphem_Forward_SPK |
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Unique Validation
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Priority |
Status |
Summary |
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P1 |
Done:SPH |
Test error thrown for non-existent SPK kernel |
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P1 |
Done:SPH |
Test error thrown for non-existent DE file |
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P1 |
Done:SPH |
Test error thrown for non-existent SPK leap second kernel |
Unique Mode Tests
None: Changes to solar system are not allowed in Command mode. -SPH
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Status |
Summary |
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Unique GUI Tests
These are tests that are unique to the GUI interface for this feature that are not covered by the standard GUI test template and procedures.
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Priority |
Status |
Summary |
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P1 |
By Inspection: SPH |
Test that change in ephemeris source is reflected in numeric results. |
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P1 |
By Inspection: SPH |
Test error is thrown when setting DE421 as source but DE424 as file. |
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