Pioneer dev forum

Is there any reason why Pioneer only uses current reference mass as source of gravity?

Before anyone starts talking about n bodies problem - no, it is not n bodies problem.
In Pioneer you have two separate categories of objects (well, three, but orbital stations don't count) - objects capable of noticeable gravitational attraction and objects obeying physics engine.
Those two categories don't overlap - anything that generates any sort of gravitational attraction is on rails, anything affected by gravity doesn't attract back.
Accounting for all sources of gravity would involve attempting to simulate interactions of multiple gravitating bodies, because gravitating bodies don't interact in Pioneer while dynamic objects don't generate gravity, it would involve adding up a relatively small (less than three digits) number of gravitational force vectors where the game currently uses one - I don't think it would put a noticeable dent in game's performance and it would improve handling of stuff like planets' moon systems significantly, as well as accuracy of projected trajectory in orbital map.

I think the basic idea is solid, take something like the Earth situation with Earth + Moon.
Very simple to do mathematically, might take a little work figuring out what bodies can currently influence the ship - I suppose you could do it the brute force way and just add ALL of the planetary bodies contributions to each ship - I was going to attack that idea but really it might not be too bad an approach to start with...