Power armor is a type of body armor used in some science fiction settings. Power armor differs from a mecha in that it fits the wearer's body and reinforces the wearer's movements, while mecha are piloted from a cockpit and can vastly differ from the pilot in size and shape.
The primary purpose of power armor is to provide wearers with far more protection than they could normally carry. A typical suit of power armor is so heavy that if it did not have power assistance, the wearer would be completely unable to move. Power armor compensates for this weight by detecting the wearer's movements and mechanically replicating them, allowing the wearer to move normally despite wearing hundreds of kilograms of body armor.
Power armor may also enhance the wearer's combat ability in various ways. The mechanical strength of the armor often allows the wearer to exert far more force than an unassisted soldier, for instance, enabling the wearer to carry heavy loads and strike with superhuman strength in close combat. Power armor may have alternate propulsion systems that allow the wearer to jump great distances or even fly. Power armor frequently has an independent life support system, protecting the wearer from harsh environments. Power armor may also have built-in weapons, communications gear, sensors, computers, and other features to aid the wearer in various situations.
- The Imperial Space Marines of Warhammer 40,000 wear power armor, as well as the sisters of the Adepta Sororitas and Elite Tau Firewarriors.
- Starcraft Marines wear a type of powered armor.
- Ripley used a powered cargo loader as an improvised suit of power armor in Aliens.
- The Mobile Infantry from Robert Heinlein's novel Starship Troopers wear power armor.
- Iron Man, from Marvel Comics, relies on a suit of power armor.
- Batman has used powered armor when fighting super-powered enemies on more then one occasion.
- Samus Aran, from the Metroid games, uses an advanced power suit designed by the Chozo.
- Master Chief and the other Spartan supersoldiers in Halo use MJOLNIR power armor.
- Body armor in Mass Effect can be outfitted with powered exoskeletons.
- In the Fallout universe, power armor was developed for the United States Army and later finds use among the Brotherhood of Steel and the Enclave.
- XCOM uses powered armor as well as flying powered armor in the first game.