Well, there's certainly a double entendre in chosing it as the name of a satellite, but it definitely comes from the name of tgat comic book character. Which itself is a play on asterisque (this symbol: *), which, of course, comes in turn from aster as you said.

His compagnon Obélix has a name which works on two levels: It can be seen as a play on obelisk (he is himself a sculptor of menhirs, which are vaguely similar to obelisks), but "obèle" is also the French word for the dagger symbol (†), which is an alternative to the asterisk.