[[WMG: Jimmy intentionality left the rocket for Sheen]]
[[WMG: The Yolkians will appear in a future episode]]
[[WMG: Sheen has been gone less than an hour earth time]]
So his parents and friends didn't even realize Sheen's absence. After all, that wreck of a show only lasted for one season.
[[WMG: Sheen comes back to earth someday.]]
Confirmed. An episode of ''WesternAnimation/TheAdventuresOfJimmyNeutron'' (The Tomorrow Boys) features a future Sheen working as a famous male model. This explains that Sheen ''did'' indeed return to earth. If he wasn't able to repair that rocket he crashed, then Jimmy must have picked him up. Either way, Dorkus must be so pleased that the bane of his existence has left.
** Maybe Nesmith was also picked up and brought to the zoo, jungle or space program he first came from.