Use of Robotics for Space Work
How Candarm Robotic Arms Provide Assistance for Application in Space
The Canadarm robotic arm has proved invaluable to Space Shuttle astronauts, and the Canadarm 2 is doing the same for the International Space Station.
The success of the Space Shuttle and International Space Station (ISS) owes a great debt to the robotic arms that are used for everything from moving cargo to delicate operations. There are three different robotic systems used in NASA space operations today: Canadarm on the Space Shuttle, and Canadarm2 and Dextre on the ISS.
Canadarm - The First Shuttle Remote Manipulator System
The Remote Manipulator System, nicknamed Canadarm after its country of origin, was first tested on the Shuttle Columbia during the mission STS-2 in November 1981. The arm is controlled by a joystick system, and complicated software algorithms translate the motion of the joysticks to the joints in the arm. Canadarm has six degrees of freedom, and has limited rotation of 160 degrees in the elbow only.
The original purpose of the arm was to do the heavy lifting that astronauts could not do during regular spacewalks. However, Canadarm's capabilities grew as the crews discovered how well the arm functioned. Canadarm has been used to tap ice off of shuttle surfaces, flip switches on satellites, capture satellites, and with a new extension designed after the Columbia disaster, inspect the shuttle surfaces for damage.
Mobile Servicing System for the International Space Station
The Mobile Servicing System on the ISS consists of 2 main parts. The first part is the robotic arm Canadarm2, which is an advanced version of the arm installed on the Space Shuttle. Canadarm2 was installed on the ISS in 2001. Canadarm2 is 57.7 feet long and has 7 motorized joints. This arm can pick up large payloads and can assist with docking the space shuttle. Canadarm2 has a Latching End Effector, so it can be moved around the ISS and attached to various ports on the station's exterior surfaces. Canadarm2 has 7 degrees of freedom, and unlike the original Canadarm, each of its joints can fully rotate up to 540 degrees.
The second part of Canadarm2 is the Mobile Base System (MBS), a platform that moves along rails covering the length of the space station, The MBS provides lateral mobility for the Canadarm2 as it traverses the ISS trusses. It was added to the station in June 2002.
Dextre - Special Purpose Dexterous Manipulator
The latest addition to Canadarm2 on the ISS is the Special Purpose Dexterous Manipulator, known as Dextre. This unit was delivered to the ISS in March 2008. Dextre is a small 2-armed robot that can be attached to Canadarm2 to perform some tasks that were previously relegated to astronauts on spacewalks. Using Dextre would reduce the amount of time that astronauts would have to spend on spacewalks.
Robotic arm systems such as Canadarm, Canadarm2, and Dextre provide important functionality to the Space Shuttle and ISS. These systems reduce the amount of time astronauts need to be outside of the vehicles and allow the astronauts to work more efficiently and safely.
Sources
NASA website (mission pages, equipment pages)
CNN website, "Space station's new robot on blink", March 14, 2008.
