Dextre

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This article is about the space robot. For Dexter, see Dexter (disambiguation).
Dextre, many of the ISS's Robotic arms and experiments, can be operated from Earth, performing tasks while the crew sleeps.
Dextre on the end of Canadarm2
Dextre, as photographed by an Expedition 26 crew member
Dextre, as photographed by an Expedition 27 crew member

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 on the International Space Station (ISS), and extends the function of this system to replace some activities otherwise requiring spacewalks. It was launched March 11, 2008 on mission STS-123.

Dextre is part of Canada's contribution to the ISS and is named to represent its dexterous nature. It is sometimes also referred to as the Canada Hand,[1] by analogy with the Canadarm and Canadarm2.[1] Dextre was designed and manufactured by MacDonald Dettwiler (MDA).[1]

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.[2]

Structure[edit]

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 Dextre 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 Dextre can be stored on Space Station grapple fixtures. At the end of Dextre's arms are ORU/Tool Changeout Mechanisms (OTCM). The OTCM 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. SARAH (Self-Adaptive Robotic Auxiliary Hand) is a three fingered hand that is designed to attach to the end of Dextre's arm.[3]

Design and delivery[edit]

Dextre was designed and manufactured by MDA Space Missions 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 (KSC) in Florida, in mid-June 2007. Once at KSC, it underwent flight verification testing followed by shuttle integration.

Installation[edit]

Dextre was launched to the ISS on March 11, 2008 aboard Endeavour on mission STS-123. 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.[4] Astronauts finished outfitting the robot during a third spacewalk on March 17, 2008.[5]

Additional usage[edit]

In early August 2004 NASA declared its intention to use Dextre (or a close copy of it) as the robotic component for the Hubble Space Telescope rescue mission. Months after awarding a contract to MDA Space Missions to provide an SPDM copy for the Hubble repair mission,[6] 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 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.[7]

Dextre was also featured in the new $5 Canadian Polymer bank note together with CanadaArm2, which Commander Chris Hadfield helped reveal aboard the International Space Station.[8]

See also[edit]

References[edit]

External links[edit]