The phrase "space marines" first appears in Robert A. Heinlein's "Misfit"<ref>"The parade ground voice of a First Sergeant of Space Marines cut through the fog and drizzle..."</ref> (1939) and is again used in "The Long Watch"<ref>"Space marines, arms reversed and heads bowed, stood guard around [the coffin]..."</ref> (1941). Heinlein's Starship Troopers (1959) is considered the defining work for the concept; for example, the actors playing the Colonial Marines in Aliens (1986) were required to read Starship Troopers as part of their training prior to filming.<ref>Template:Cite web</ref> Heinlein intended for the capsule troopers of the Mobile Infantry to be an amalgam of the shipborne aspect of the US Marine Corps relocated to space and coupled with the battlefield delivery and mission profile of US Armyparatroopers.
As a gaming concept, space marines play a major role in the Warhammer 40,000 miniatures wargame, in which they are genetically altered super-soldiers and the most powerful fighting forces available to the Imperium of Mankind. In computer games, playing a space marine in action games was popularized by id Software's Doom series, first published in 1993. It is a convenient game back-story as it excuses the presence of the character on a hostile alien world with little support and heavy weaponry. Some critics have suggested it has been overused to the point of being an action game cliché.<ref>Template:Cite journal</ref>
==Characteristics== Template:Original research In film and television space marines often appear in squads, while in action games the protagonist marine is often alone (although this is more due to game limitations) or transferred between different units as the game progresses. In their amphibious role, marines are usually transported by "drop ships" and/or "drop pods", and are supported on the ground by infantry fighting vehicles or lighter vehicles.
==Non-fiction aspects== The United States Marine Corps's Project Hot Eagle considers the use of spacecraft to deliver marines to a target on the ground. "Within minutes of bursting into the atmosphere beyond the speed of sound – and dispatching that ominous sonic boom – a small squad of Marines could be on the ground and ready to take care of business within 2 hours."<ref>Template:Cite web</ref>
==Appearances in fiction== <!-- Please, include both the names of fictional works and the space marine corps names, regardless whether there is such article or not. The list is sorted by the years when works have been first published. -->