The space marine, an archetype of military science fiction, is a kind of soldier who operates in outer space or on alien worlds. Historical marines fulfill multiple roles: ship defence, boarding actions, landing parties, and general-purpose high-mobility land deployments that operate within a fixed distance of shore or ship. By analogy, hypothetical space marines would defend allied spaceships, board enemy ships, land on planets and moons, and satisfy rapid-deployment needs throughout space.
