it's not just about space travel, it's a song about the personal impact of relativistic space travel on one astronaut's family, written by the, now, Chancellor of Liverpool John Moores University and a doctor of astrophysics. How much more apropos can you get? :)
You can't do without "Rockin' In the Orbit" which uses Sputnik's "beep" as percussion (1958 Jimmie Haskell - Rockin' In The Orbit (Space Satellite)
Major Tom seems too obvious, but there it is.
Also sprach Zarathustra, of course.
There's something that makes me think of Talking to the Moon by Atomic Cat (Atomic Cat - Talking to the Moon [FULL-HD] HQ-Sound
) a French group. I'd always thought of the "I'm talking to the moon" lyric as being a metaphor, but in this case it could be literal.