[gngeal]

Hah, my high school memories - a graphical gravity simulator project for my CS class, leaking energy due to the use of a very naive integrator (the Euler method for ODEs).

You might want to try Stormer-Cowell, it's sort of a gold standard in orbit simulation.

UPDATED: Hmm, now that I think of it, this would probably profit more from a variable step method. Some of the close approaches seem to be really close for a fixed-step integrator.

[jbochi]

Thanks! I did not know Stormer-Cowell, but googling it, I've found a comparision to DROMO, suggesting that it's even more stable: http://www.congrex.nl/11c01proceedings/Papers/2225317%20Pela...

I'll try both if I find the time :)

[tikhonj]

Heh, that's exactly what I made with a friend for a physics project in high school. We didn't even consider different methods--we used the Euler method because it's the most intuitive. I didn't even know it had a name!

Good times.