The plan to send Baby Smurf to another planet in a rocket as the last survivor of Earth is based on part of the origin story of Superman, when he (as Kal-El) was sent to Earth as a baby in a rocket prior to Krypton's destruction.
While the episode's title is "The Comet is Coming," no one actually uses the term "comet." All the characters refer to the comet as a "flaming star."