Love science finction ? Love rock ? Why not combine them ?
Certainly many have, starting with Pink Floyd's "Astronomy Domine" "Interstellar Overdrive" from their The Piper at the Gates of Dawn and continuing on "A Saucerful of Secrets"
While Pink Floyd were the first, Hawkind were probably the most committed. Their double live album Space Ritual (1973) ("88 minutes of brain-damage") featured sci-fi author Michaeel Moorcock supplying the lyrics for most of the spoken word sections of the album.
The most famous venture into space is probably David Bowie's, "Space Oddity" (1969). The most successful recent venture has probably been by The Flaming Lips ('Yoshimi Battles the Pink Robots")
Biggest collection of space-rock band ever ? Probably the Strange Dayz Festival held from '97 to 2000 in the Us: three continuous days of space-rock featuring such unknown bands as Alien Planetscapes, Architectural Metaphor, Quarkspace, Melting Euphoria, Pressurehed, Nucleon and Bionaut