Remote Manipulator System
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The Remote Manipulator System (RMS) or Canadarm (Canadarm 1) on the Space Shuttle, is a mechanical arm that maneuvers a payload from the payload bay of the space shuttle orbiter to its deployment position and then releases 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 RMS 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 RMS will play this role in all future shuttle missions.
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[edit] Specifications
The RMS arm is 15 metres (50 ft 3 in) long and 38 centimetres (15 inches) in diameter and has six degrees of freedom. It weighs 410 kg (905 pounds), and the total system weighs 450 kg (994 lb). The RMS has six joints that correspond roughly to the joints of the human arm, with shoulder yaw and pitch joints; an elbow pitch joint; and wrist pitch, yaw, and roll joints. The end effector is the unit at the end of the wrist that actually grabs, or grapples, the payload. The two lightweight boom segments are called the upper and lower arms. The upper boom connects the shoulder and elbow joints, and the lower boom connects the elbow and wrist joints. The RMS arm attaches to the orbiter payload bay longeron at the shoulder manipulator positioning mechanism. Power and data connections are located at the shoulder MPM.
[edit] Capabilities
The RMS is capable of deploying or retrieving payloads weighing up to 29 metric tonnes (65,000 pounds) in space, though the arm motors are unable to move the arm's own weight when on the ground. The RMS can also retrieve, repair and deploy satellites; provide a mobile extension ladder for extravehicular activity crew members for work stations or foot restraints; and be used as an inspection aid to allow the flight crew members to view the orbiter's or payload's surfaces through a television camera on the RMS.
The basic RMS configuration consists of a manipulator arm; an RMS display and control panel, including rotational and translational hand controllers at the orbiter aft flight deck flight crew station; and a manipulator controller interface unit that interfaces with the orbiter computer. Most of the time the arm operators see what they are doing by looking at the Advanced Space Vision System screen next to the controllers.
One flight crew member operates the RMS from the aft flight deck control station, and a second flight crew member usually assists with television camera operations. This allows the RMS operator to view RMS operations through the aft flight deck payload and overhead windows and through the closed-circuit television monitors at the aft flight deck station.
[edit] Development
Spar Aerospace Ltd., a Canadian company, designed, developed, tested and built the RMS. (Spar was later acquired by Richmond-based MacDonald Dettwiler & Associates.) The main controls algorithms were subcontracted to Dynacon Inc. of Toronto. CAE Electronics Ltd. in Montreal provides electronic interfaces, servoamplifiers and power conditioners. Dilworth, Secord, Meagher and Associates Ltd. in Toronto is responsible for the RMS end effector. Rockwell International's Space Transportation Systems Division designed, developed, tested and built the systems used to attach the RMS to the payload bay of the orbiter.
[edit] Usage
Since its first usage during STS-2 in 1981 on Columbia, the RMS has been used on over 50 shuttle missions. It was first flown on Challenger during STS-7 in 1983. Then in 1985 it was first used aboard Discovery during STS-51-C. The RMS onboard Challenger was lost during the Challenger disaster in 1986. It was used on Atlantis first during STS-27, and on Endeavour during STS-49 (her first flight).
Since the installation of the Canadarm2 on the International Space Station, the two arms have been used to hand over segments of the station for assembly from the RMS to the Canadarm2; the use of both elements in tandem has earned the nickname of 'Canadian Handshake' in the media.
Following the Columbia disaster, the RMS has been used on every space shuttle flight to inspect the heat shield for damage that may have been caused during launch. It is likely that the arm will be a part of all future shuttle missions.
[edit] See also
- Canadarm2, a robotic arm that is part of the International Space Station's Mobile Servicing System
- European Robotic Arm, a second robotic arm to be installed on the ISS
- Space Shuttle program
