Very strange bug I've discovered when trying to do a very small solar system (for a Kerbal Space Program run...).
Setting a planet to have a very close orbit (~5-10m km) will cause it to have an extremely eccentric orbit no matter what. It only seems to affect planets with very close orbits. And, what's more, after a few 5-day increments, planets will seemingly go "off the rails" and disappear completely, setting their orbital distance and some of their other properties to "NaN".
I imagine there's some issue with running such small scale solar systems, but it would be pretty neato if this could be fixed.
(and, as an aside, maybe being able to enter custom properties for stars, as well. The solar system is KSP breaks many things about physics, but being able to handwave those things and just put in the numbers to stars that you need would be cool).
DB attached for debugging, it has one planet that currently is displaying the crazy eccentricity issue as well as two planets that have gone to NaN land.