The Space Station Remote Manipulator System (SSRMS), known as Canadarm2, is the first component of the Mobile Servicing System. Although similar to the Shuttle Canadarm, this 17 metre manipulator is somewhat larger and incorporates many advanced features, including the ability to self relocate.
The arm has the capacity to handle large ISS modules and structural elements. It will initially be used to assemble the Station. In the future, it will capture and dock unmanned resupply spacecraft to the ISS and perform routine maintenance tasks.
Canadarm2 will normally move along the Space Station on the Mobile Base System, but it also has the ability to "walk" from place to place by moving from one grapple fixture on the exterior of the structure to the next, like an inchworm.
Canadarm2 is built with Orbital Replaceable Units (ORUs) which are components that can be removed and then replaced by either an astronaut or the Special Purpose Dexterous Manipulator. It is equipped with four television cameras, two mounted on the booms and one near each tip. These cameras feed images to the astronauts operating the arm from the Robotic Workstation inside the Station. An advanced version of the Canadian Space Vision System improves the ability of Canadarm2 operators to keep track of the position, orientation and movement of payloads being grappled.