Space Crusade (there is no link because it’s basically only one track).
This is actually the Atari ST version of the music; I’m posting the Spectrum version because 1) it is completely identical thanks to the Spectrum using audio cassettes as its storage format and being able to do whatever the hell it wanted with respect to music and 2) it’s the only version on youtube that isn’t the shitty Amiga/PC Adlib arrangments.