GMAT DRO mission to the moon

[Maniraj@123]

Hi all I am new to this forum and GMAT. For my thesis, while working on GMAT, I am encountering a Runge-Kutta error in GMAT when simulating an orbit similar to facing the moon, with an increased altitude in periapsis and a reduced altitude in apoapsis (This results in the periapsis length being greater than the apoapsis length.). How can I resolve this issue?

 

[Eddie C.]

Hello and welcome. Not sure what exactly do you mean/what is the problem. In a very profane definition, Periapsis (Pe) is always smallest altitude (to surface) or smallest radius (to body's center) of an elliptical orbit. So, according to your question, Pe "length" (Radius or Altitude) cannot be greater than Ap "length", because in such a case there is a role reversal between Pe and Ap.
Moreover, did you try to write/simulate in GMAT a simpler, geocentric, low Ecc orbit? Do you have the same errors?
Last but not least - did you tried to simulate and visualize your desired orbit ...in Orbiter?

 

[Maniraj@123]

Thank you for the response! I tried adjusting the perigee and apogee radius dimensions, and now I can simulate the orbit without any errors. However, when I activate the lunar perturbation, the shape of the orbit changes. I attempted to manoeuvre at the perigee and apogee, but the orbit remains imperfect. How can I correct this error?

 

[Eddie C.]

Thank you for the response! I tried adjusting the perigee and apogee radius dimensions, and now I can simulate the orbit without any errors. However, when I activate the lunar perturbation, the shape of the orbit changes. I attempted to manoeuvre at the perigee and apogee, but the orbit remains imperfect. How can I correct this error?

Hi again, trying best to help.
Here is a post by @BrianJ which contains some useful links on theory and also has attached a very good (to my opinion) "walkthrough" style note for an Orbiter simulated Artemis-1 flight which includes a DRO.
In the above post there is also a link to another thread which contains...an Youtube link for a great visualization of a DRO.

You may use the above info to check if your basic orbital parameters are correct.

Feel free to come back with questions any time.