The Shatner thread kind of brings this topic back up, but going through his set list, a lot of the songs have nothing (zero zip zilch nada) to do with space/rocketry (Bohemian Rhapsody, Iron Man, Twilight Zone) so how about putting together a setlist of songs which actually do mention space travel, rocketry or astronomy?
Elton John's "Rocket Man" is the obvious lead-off.
Bowie's "Space Oddity" (as well as its sequel "Ashes to Ashes") and "2000 Light Years from Home" by the Rolling Stones of course as already mentioned higher up the thread.
"Man on the Moon," R.E.M.: although the song at first seems to buy into the lunar-conspiracy theories, Michael Stipe has said it is actually about the gullibility of those who believe in them.
"Sleeping Satellite" by Tasmin Archer in the early 1990s, wondering why we haven't followed up the Apollo flights.
"This Life," by Bruce Springsteen, 2009: On track 6 of the album is, "A bang then stardust in your eyes, A billion years or just this night, Either way it'll be all right, A blackness then the light of a million stars..(it continues)...
At night at my telescope alone, This emptiness I've roamed, Searching for a home... A beauty in the neighborhood, This lonely planet never looked so good...(the song ends with the line)...This life, this life and then the next, I finger the hem of your dress, My universe at rest."