Technically, the troopers in "Starship Troopers" were known as 'The Mobile Infantry,' storm troopers, shock troops, marines, and army special forces all rolled into one.

The military personal featured in "Aliens" and "Space: Above and Beyond" were 'space marines.'

'Space Marines' were also featured in the Japanimation show "Space Battleship Yamato/Star Blazers." In the original Japanese show they were called 'The Space Calvary."

In the James Bond movie "Moonraker," Drax's space station is attacked by U.S. Astronaut Marines--different beast entirely.

Faction in Warhammer 40K. Imperium of Man's best soldiers. An outcome of lots of genetic engineering, rigorious training and awsomly looking armour. have guns that shoot "bolts" - somethinh between a bullet and a rocket. Has access to lots of powrefull weapons and venchiles. main drawback - old gear, because in W40K humans are affraid of new technologies. although pretty awesome, powerfull adn fearless they rarely win in real life because of stupid people playing with them

the space marine could be compared to the cowboys of the old west, or pirates of the high seas. they are tough, smart, and always have the biggest guns or are just insanely strong. the idea of the space marine has been around for a while, but only in recent years have they been popular in books, movies, and videogames. you might not realise it, but you can look in almost any sci fi movie and find a space marine. pretty soon you wont be able to find any children playing "cowboys and injuns" but youll find many playing "spartans and covenants" the only difference is that theyre playing it online via xbox live.

oh yeah, and dont forget the novel/movie starship troopers

Originating from the Warhammer 40,000 Space Marine race/faction, the term has became popular for any heavily armoured and armed soldier in a futuristic (near or far) setting.

The Term is normally used for the elite as described before, but can be used to describe any trooper in power armour, for example the Starcraft marines are often nicknamed (or accused of being) Space Marines and they're not elite at all (mainly being physchologically adjusted inmates). Similar story can be said of C&C3 Zone Troopers, Mobile Infantry in Starship Troopers etc, although the term is very rarely used for Fallout Brotherhood of Steel paladins as they have nothing to do with space (but their attitude and appearance almost mirrors the Space Marines word for word)

The Terms is often only used for humans.