# What programs simulate the orbit of an asteroid over long periods of time?

I am trying to simulate the orbit of an asteroid over a long period of time in order to see the change in the orbit due to a constant force applied to the asteroid. Initially, I used GMAT to simulate the orbit but quickly ran into an error that prevented me from running it more than ~100 years. Does anyone know how to fix this issue? If not, what programs would be able to do this and not run into the same error as GMAT? Thank You.

This was the error:

PlanetaryEphem (sub)class exception: Requested epoch 95008.513478505 is not on the DE file
'D:\GMAT\bin\..\data\planetary_ephem\de\leDE1941.405'.

• DE405 should cover 1599 to 2201 (list of JPL ephemerides), assuming that time you quote is a MJD, then that should be 2119-01-01 and inside the range. Is GMAT using a cut-down version of DE405 that doesn't cover as big a range ? The other option if GMAT supports it (the format is slightly different so it's not always a drop-in) is to switch to DE430 which is (a) more modern and more accurate and (b) has a bigger range; up to 2650 Jan – astrosnapper May 2 '20 at 17:15
• I am unsure if Gmat is using a cut-down version. I have to do some research to find that out. I will try switching to DE430 and see if it is possible. Preferably, I would be able to run simulations for 1000+ years (the longer the better); would you say that is not possible using Gmat or DE430? – Will Rosenberg May 2 '20 at 18:53