Solar System

Lead: SPH

Developer: WCS

Tester: JMB

 

 

Spec User’s Guide

Explore

Known Bugs

Failing Tests

Other Findings

Requirements

Interface/Functional Spec

Overview

Description

Fields

GUI

Remarks

Behavior When Changing the Coordinate System

Examples

Test Procedures

Assumptions

Existing Tests

Recommended Additional Tests

 

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.

 

ID

Requirements

FRR-xyz

The requirement.

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. 

 

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. 

 

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.

 

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.

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.

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. 

 

Priority

Status

Summary

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_*

 

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

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

 

 

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_*

P1

Done: SPH

Test ephemeris update interval at zero and non zero values.

See files named:

SolarSystem_EphemUpdateInterval_*

P1

Done:SPH

Test providing user defined SPK kernel for main solar system ephemeris

 

Recommended Additional Tests

 

Nominal Tests

Priority

Status

Summary

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

 

 

 

 

 

 

 

 

Edge/Corner/Stress

Priority

Status

Summary

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

 

 

 

 

 

 

 

 

Unique Validation

 

Priority

Status

Summary

P1

Done:SPH

Test error thrown for non-existent SPK kernel

P1

Done:SPH

Test error thrown for non-existent DE file

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

 

Priority

Status

Summary

 

 

 

 

 

 

 

 

 

 

 

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.

 

Priority

Status

Summary

P1

By Inspection: SPH

Test that change in ephemeris source is reflected in numeric results.

P1

By Inspection: SPH

Test error is thrown when setting DE421 as source but DE424 as file.