Here is a photo of the Shuttle Remote Manipulator System (SRMS), or Canadarm (Canadarm 1). Backdropped against Earth's horizon and the blackness of space, Endeavour's Canadian-built robot arm appears amidst elements of the International Space Station. Endeavour had been docked for almost two weeks during the STS-126 mission at the orbital outpost when this image was taken. Image Credit: NASA

The Canadarm (Canadarm 1), is a mechanical arm used on the Space Shuttle to maneuver a payload from the payload bay of the orbiter to its deployment position and then release it. It can also grapple a free-flying payload, maneuver it to the payload bay of the orbiter and berth it in the orbiter. It was first used on the second Space Shuttle mission STS-2, launched November 13, 1981. Since the destruction of Space Shuttle Columbia during STS-107, NASA has outfitted the SRMS with the Orbiter Boom Sensor System, a boom containing instruments to inspect the exterior of the shuttle for damage to the thermal protection system. It is expected the SRMS will play this role in all future shuttle missions.