voyage vs space travel

voyage and space travel both are nouns.

Word	Noun	Adjective	Verb	Adverb
voyage	Yes	No	Yes	No
space travel	Yes	No	No	No

As nouns, space travel is a hyponym of voyage; that is, space travel is a word with a more specific, narrower meaning than voyage:

Other hyponyms of voyage include crossing, spacefaring, spaceflight.

voyage (noun)	space travel (noun)
a journey to some distant place	a voyage outside the Earth's atmosphere
an act of traveling by water

voyage (verb)	space travel (verb)
travel on water propelled by wind or by other means