Bug? Ship doesn't stay on Interloper

[BlueRaja]

Just played the game for the first time. Landed on "Interloper", walked around for a bit, and when I went back to my ship, it was floating out in space 15km away. Cool.

[Solar]

Did the interloper go around the sun or come close to hitting any astral body while you were on it? If so, the gravity could have either flung it off the interloper and onto the planet, or could have been blasted out into space.
Also, if you go around the sun with your ship on the interloper, even if its on the cold side, it always falls off due to immense force and gravity, and either falls into the sun or gets doomed to drift among the cosmos, barren and alone until the loop ends.