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Space Station Extravehicular Activity

Preparing for Hands-On Construction in Outer Space

IMAGE: STS-88 astronauts performs EVA
STS-88 Mission Specialists Jerry Ross and James Newman work together during the first International Space Station assembly mission. The Zarya module solar array is in the background.

Recognizing the challenge and complexity of building the International Space Station, NASA has made a concerted effort for more than a decade to develop and flight test the spacewalk equipment needed; refine spacewalk training procedures; and build spacewalk, or extravehicular activity, experience among astronauts, engineers and flight controllers. Since 1991, more than a dozen "practice" spacewalks have been conducted during space shuttle flights as part of NASA's preparations. In addition, three servicing missions for the Hubble Space Telescope have helped prepare for the intricate work needed to build the station. Many of the astronauts who gained experience during these "practice" spacewalks are bringing that knowledge to bear during spacewalks in the station's orbital assembly.

The flight-testing of EVA equipment designed for use aboard the International Space Station began on the first spacewalk NASA conducted after the space shuttle's return to flight following the Challenger accident. On shuttle mission STS-37 in April 1991, Astronauts Jerry Ross and Jay Apt performed a spacewalk to test a Crew and Equipment Translation Aid cart designed for use in assisting astronauts to move about the football field-long truss of the completed station. Two such carts are now planned for launch to the station during its assembly.

IMAGE: STS-96 Astronaut Daniel Barry
Astronaut Daniel Barry performs external tasks on the U.S.-built Unity Node of the International Space Station during the STS-96 mission.

Since 1991, other spacewalks have evaluated new tethers, tools, foot restraints, handling large masses, a jet pack "life jacket," spacesuit enhancements and even the planned station lettering and toolboxes.

To prepare for International Space Station assembly in earnest, NASA announced the first International Space Station EVA assembly crew, Ross and Jim Newman on STS-88, in August 1996. In June 1997, five more crews of station assembly spacewalkers were named to complete the first six shuttle assembly missions, some of them more than two years ahead of their scheduled mission, much earlier than is traditional. The early naming of crewmembers has allowed the astronauts additional time to train for their complex and crucial missions.

EVA Details
Spacewalk History
IMAGE: Skylab 3 spacewalk
Astronaut James Lousma works outside the United States space station during the third crewed Skylab mission on August 6, 1973.
Related Links
ISS: The NASA Research Plan, an Overview
(Also available as a pdf file - 979k)
International Space Station Utilization Conference

Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 03/04/2004
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