TransX TransX Problem With Nonspherical Grav

[Lanzfeld]

I am learning to use Trans X first (before IMFD) and I have been following tutorials on the web for a moon shot with a free return.

Trans X works okay for this (not great but close) with Nonspherical Gravity Source OFF but when I turn it ON and try to use Trans X even for a simple moon shot (no free return) the numbers it "predicts" (PeD) are way off after I do the burn.

I have 3.13 but is it not compatible with Nonspherical Gravity ???

EDIT: To be more specific: I set up a 100K pass above moon at Inc of 175 degrees (Apollo/Free Return type) and after burn I end up with a 15M (million) pass at 5 degrees. Way off target even though my burn was right on (green cross centered and delta V=0)

 

[Linguofreak]

I do not believe TransX models non-spherical gravity. Still, I generally don't find it to be too much of a problem. A fairly minor course correction should put you back on track. 15 M is still fairly close, and if you make your correction burn early, it shouldn't take much delta-V to fix. Real spacecraft have to do course corrections too.

 

[agentgonzo]

TransX does not model non-spherical gravity sources. It is also not massively accurate for Earth-Moon trajectories due to the model it uses (patched conics).

As Linguo said, you will need to perform mid course corrections on your journeys, not just rely on one-burn-to-rule-them-all.