Planets / moons need to be updated/gravitated continuously to maintain proper orbits. Ships, however, could just get ignored when far away, and respawned when the player is close. Ship and bomb death is still handled by banishment to faraway lands, which is strange and inefficient.
Planets and ships do maintain reasonable "active" flags, with ships inheriting the state of their parent planet, but the flags aren't used to prevent wasteful calculations.
Planets / moons need to be updated/gravitated continuously to maintain proper orbits. Ships, however, could just get ignored when far away, and respawned when the player is close. Ship and bomb death is still handled by banishment to faraway lands, which is strange and inefficient.
Planets and ships do maintain reasonable "active" flags, with ships inheriting the state of their parent planet, but the flags aren't used to prevent wasteful calculations.