I'm trying to model some missions in NASA's GMAT and I'm having a problem with the Orbiter 2016 Keplerian elements. I load up the Delta Glider/Docked at ISS scenario, bring up the Scenario Editor, and open GL-02 (the one docked with the ISS). I'm grabbing the Keplerian elements from the Orbital Elements dialog in req. equator as follows:
Looking at the Orbiter map MFD the spacecraft is over northeaster China. If I advanced to periapsis, it's over the Pacific southeast of Japan.
Back to GMAT I'm using the default propagator. RungeKutta89 with JGM-2 degree 4/4 gravity model. No solar radiation pressure or atmospheric drag. No tides. Includes the moon and sun as extra point masses. I forgot to mention, I have non-spherical gravity sources enabled in orbiter but no other perturbations. I setup a very simple mission sequence to propagate to periapsis. I look at the ground track in GMAT and I start south of Australia and end after a short time over the south pacific.
Extending both orbiter and GMAT to apoapsis it appears that orbiter ends near western Africa on a northward track and GMAT ends in the middle of the sahara on a southern track.
My guess is one or more of the conversions has the wrong sign or is using a different 0 point. Anyone have any thoughts?
- SMa 6735km
- ECC 0.000914735
- Inc 51.5853
- LAN 166.492
- LpE 331.337
- Tr anomaly 312.449
- MJD 51982.02900
Looking at the Orbiter map MFD the spacecraft is over northeaster China. If I advanced to periapsis, it's over the Pacific southeast of Japan.
Back to GMAT I'm using the default propagator. RungeKutta89 with JGM-2 degree 4/4 gravity model. No solar radiation pressure or atmospheric drag. No tides. Includes the moon and sun as extra point masses. I forgot to mention, I have non-spherical gravity sources enabled in orbiter but no other perturbations. I setup a very simple mission sequence to propagate to periapsis. I look at the ground track in GMAT and I start south of Australia and end after a short time over the south pacific.
Extending both orbiter and GMAT to apoapsis it appears that orbiter ends near western Africa on a northward track and GMAT ends in the middle of the sahara on a southern track.
My guess is one or more of the conversions has the wrong sign or is using a different 0 point. Anyone have any thoughts?