Hello everyone, I’ve recently encounter this issue:
I have 2 scripts, let’s call them script A and script B. Script A contains almost no calls to Orekit, all it does is call its Constants class to get some data, and then solves a minimization problem based on an analytical formulation of an orbital mechanics problem. Then, I save the solution computed to a txt file which is used to initialize script B. Script B makes instead extensive use of Orekit as it is meant to propagate the solution computed by the analytical model in a more physically meaningful dynamical model. In particular, it uses a NumericalPropagator to propagate the effect of the maneuvers computed in script A and it also uses a DSSTPropagator to compute the corresponding mean elements. However, when I run script B after running script A, NumericalPropagator returns this error:
JavaError: <super: <class 'JavaError'>, <JavaError object>>
Java stacktrace:
java.lang.ArrayIndexOutOfBoundsException: 1
at org.orekit.forces.gravity.OceanTidesField$TideHarmonics.getNormalizedCnm(OceanTidesField.java:223)
at org.orekit.forces.gravity.potential.CachedNormalizedSphericalHarmonicsProvider$Generator.fillArray(CachedNormalizedSphericalHarmonicsProvider.java:205)
at org.orekit.forces.gravity.potential.CachedNormalizedSphericalHarmonicsProvider$Generator.generate(CachedNormalizedSphericalHarmonicsProvider.java:158)
at org.orekit.utils.GenericTimeStampedCache$Slot.generateAndCheck(GenericTimeStampedCache.java:793)
at org.orekit.utils.GenericTimeStampedCache$Slot.<init>(GenericTimeStampedCache.java:447)
at org.orekit.utils.GenericTimeStampedCache.selectSlot(GenericTimeStampedCache.java:369)
at org.orekit.utils.GenericTimeStampedCache.getNeighbors(GenericTimeStampedCache.java:292)
at org.orekit.forces.gravity.potential.CachedNormalizedSphericalHarmonicsProvider.onDate(CachedNormalizedSphericalHarmonicsProvider.java:127)
at org.orekit.forces.gravity.HolmesFeatherstoneAttractionModel.gradient(HolmesFeatherstoneAttractionModel.java:280)
at org.orekit.forces.gravity.HolmesFeatherstoneAttractionModel.acceleration(HolmesFeatherstoneAttractionModel.java:1039)
at org.orekit.forces.gravity.OceanTides.acceleration(OceanTides.java:176)
at org.orekit.forces.ForceModel.addContribution(ForceModel.java:109)
at org.orekit.propagation.numerical.NumericalPropagator$Main.computeDerivatives(NumericalPropagator.java:899)
at org.orekit.propagation.integration.AbstractIntegratedPropagator$ConvertedMainStateEquations.computeDerivatives(AbstractIntegratedPropagator.java:758)
at org.hipparchus.ode.ExpandableODE.computeDerivatives(ExpandableODE.java:134)
at org.hipparchus.ode.AbstractIntegrator.computeDerivatives(AbstractIntegrator.java:265)
at org.hipparchus.ode.AbstractIntegrator.initIntegration(AbstractIntegrator.java:217)
at org.hipparchus.ode.nonstiff.EmbeddedRungeKuttaIntegrator.integrate(EmbeddedRungeKuttaIntegrator.java:196)
at org.orekit.propagation.integration.AbstractIntegratedPropagator.integrateDynamics(AbstractIntegratedPropagator.java:477)
at org.orekit.propagation.integration.AbstractIntegratedPropagator.propagate(AbstractIntegratedPropagator.java:425)
at org.orekit.propagation.integration.AbstractIntegratedPropagator.propagate(AbstractIntegratedPropagator.java:385)
The force models I use are defined like this:
n, m = 4, 4;
nonSphericalGravity = HolmesFeatherstoneAttractionModel(FramesFactory.getITRF(IERSConventions.IERS_2010, True),
GravityFieldFactory.getConstantNormalizedProvider(n,m));
sunThirdBody = ThirdBodyAttraction(CelestialBodyFactory.getSun());
moonThirdBody = ThirdBodyAttraction(CelestialBodyFactory.getMoon());
dragForce = DragForce(HarrisPriester(CelestialBodyFactory.getSun(), earth), IsotropicDrag(area, CD));
srpForce = SolarRadiationPressure(CelestialBodyFactory.getSun(),
Re, IsotropicRadiationSingleCoefficient(area, CR));
oceanicTides = OceanTides(FramesFactory.getITRF(IERSConventions.IERS_2010, True),
Re, mu, n, m, IERSConventions.IERS_2010,
TimeScalesFactory.getUT1(IERSConventions.IERS_2010, True));
solidTides = SolidTides(FramesFactory.getITRF(IERSConventions.IERS_2010, True),
Re, mu, GravityFieldFactory.getConstantNormalizedProvider(n, m).getTideSystem(),
IERSConventions.IERS_2010, TimeScalesFactory.getUT1(IERSConventions.IERS_2010, True),
[CelestialBodyFactory.getSun(), CelestialBodyFactory.getMoon()]);
forces = [nonSphericalGravity, sunThirdBody, moonThirdBody, dragForce, srpForce, oceanicTides, solidTides];
(I know that I probably shouldn’t add OceanicTides and SolidTides since they don’t have a DSST equivalent, but let’s sidestep that for a moment)
What is really weird is the fact that if I restart my console and run script B (without running script A) the propagator doesn’t encounter this error. It also works fine if I run B → A → B on a fresh console. Basically the propagation fails if A is the absolute first script run.
Any ideas on what is causing this issue?
