Calculate current position on unpowered sections directly

[quyxkh]

As I understand it, most visibly during time acceleration, stable orbits that stay outside an atmosphere and within an SOI decay due to rounding errors -- so real-world reasoning no longer works. Similarly, orbits with periapses that dip into an atmosphere survive far too long.

You can directly calculate a 2-body-conic position given just the conic, start position and timestamp, and there's any number of at least roughly right direct approximations for per-orbit energy loss by say entry velocity and periapsis and cross-section. Seems to me reasonable and cheap implementations of those could make the sim much more satisfying for me, and I think for anybody who's already got some grasp of the basics, that I'm in here begging to have them implemented. Pretty please?