Special Purpose Dexterous Manipulator
Encyclopedia
Dextre, also known as the Special Purpose Dexterous Manipulator (SPDM), is a two armed robot, or telemanipulator, which is part of the Mobile Servicing System
Mobile Servicing System
The Mobile Servicing System , better known by its primary component Canadarm2, is a robotic system and associated equipment on the International Space Station...
on the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
(ISS), and extends the function of this system to replace some activities otherwise requiring spacewalks
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
. It was launched March 11, 2008 on mission STS-123
STS-123
-Mission parameters:* Mass:* Orbiter liftoff: * Orbiter landing: * Perigee: 336 kilometers * Apogee: 346 kilometers * Inclination: 51.6 degrees* Period: 91.6min-Mission payloads:...
.
Dextre is part of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
's contribution to the ISS and is named to represent its dexterous nature. It is sometimes also referred to as the Canada Hand, by analogy with the Canadarm and Canadarm2. Dextre was designed and manufactured by MacDonald Dettwiler
MacDonald Dettwiler
MacDonald, Dettwiler and Associates Ltd. is a Richmond, British Columbia-based Canadian aerospace, information services and products company, employing over 3000 people throughout Canada, the United States and the United Kingdom, under the MDA brand name....
.
In the early morning of February 4, 2011, Dextre completed its first official assignment which consisted in unpacking two pieces for Kounotori 2 while the on-board crew was sleeping.
Structure
Dextre resembles a headless torso fitted with two extremely agile, 3.35 metres (11 ft) arms. The 3.5 meter long body pivots at the "waist". The body has a grapple fixture at one end that can be grasped by the larger Space Station Arm, Canadarm2 so that the SPDM can be positioned at the various Orbital Replacement Unit (ORU) worksites around the Space Station. The other end of the body has an end effector virtually identical to that of Canadarm2, so that the SPDM can be stored on Space Station grapple fixtures Unit/Tool Changeout Mechanism (OTCM). It has built-in grasping jaws, a retractable socket drive, a monochrome TV camera, lights, and an umbilical connector that can provide power, data, and video to/from a payload.The lower body of Dextre has a pair of orientable colour TV cameras with lights, a platform for stowing ORUs, and a tool holster. The tool holster is equipped with three different tools used to perform various tasks.
Design and delivery
Dextre was designed and manufactured by MDA Space MissionsMDA Space Missions
MDA Space Missions is an operating unit of MacDonald Dettwiler and Associates, comprising the following wholly owned subsidiaries:* Alliance Spacesystems, a space robotics company based in Pasadena, California, Boulder, Colorado and Signal Hill, California....
as contracted by the Canadian Space Agency, which will oversee its future operations and the necessary training of station crews.
It completed all necessary testing and was delivered to the Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
(KSC) in Florida, in mid-June 2007. Once at KSC, it underwent flight verification testing followed by shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
integration.
Installation
Dextre was launched to the ISS on March 11, 2008 aboard EndeavourSpace Shuttle Endeavour
Space Shuttle Endeavour is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States. Endeavour was the fifth and final spaceworthy NASA space shuttle to be built, constructed as a replacement for Challenger...
on mission STS-123
STS-123
-Mission parameters:* Mass:* Orbiter liftoff: * Orbiter landing: * Perigee: 336 kilometers * Apogee: 346 kilometers * Inclination: 51.6 degrees* Period: 91.6min-Mission payloads:...
. It "woke up" and activated heaters needed for keeping its joints and electronics warm after receiving power from the space station's Canadarm2 on March 14. During the mission's second spacewalk on March 16, spacewalking astronauts attached the two 3.35 metres (11 ft) arms to the robot's main body and further prepared the machine for its handyman job on the station. After the spacewalk, crew members hooked Dextre back up to the station robotic arm to keep it warm and to allow NASA to perform tests to ensure all of Dextre's electronics were working properly. Later that day, the crew tested all of its joints and brakes. Astronauts finished outfitting the robot during a third spacewalk on March 17, 2008.
Additional usage
In early August 2004 NASANASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
declared its intention to use Dextre (or a close copy of it) as the robotic component for the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
rescue mission. Months after awarding a contract to MDA Space Missions
MDA Space Missions
MDA Space Missions is an operating unit of MacDonald Dettwiler and Associates, comprising the following wholly owned subsidiaries:* Alliance Spacesystems, a space robotics company based in Pasadena, California, Boulder, Colorado and Signal Hill, California....
to provide an SPDM copy for the Hubble repair mission, NASA then canceled the mission in favour of flying a Shuttle mission to perform the repairs/upgrades. NASA cited excessive risks and new-found confidence in the Space Shuttle external tank
Space Shuttle external tank
A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...
as reasons for the cancellation.
Dextre was the subject of an April Fool's Day joke article on April 1, 2008 on NASA's APOD website.
External links
- Canadian Space Agency page on Dextre
- Dextre: STS Mission 123 CTV NewsCTV NewsCTV News is the news division of the CTV Television Network in Canada. The name CTV News is also applied as the title of local and regional newscasts on the network's owned-and-operated stations , which are closely tied to the national news division...
animation series showing Dextre in operation