Related topics: international space station , astronauts , nasa , hubble space telescope , space station
Extra-vehicular activity
hideExtra-vehicular activity (EVA) 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 (a spacewalk), but also applies to an EVA made on the surface of the Moon (a moonwalk). In the later lunar landing missions (Apollo 15, 16, and 17) the command module pilot (CMP) did an EVA to retrieve film canisters on the return trip; he was assisted by the lunar module pilot (LMP) who remained at the open CM hatch. These trans-Earth EVAs were the only spacewalks ever conducted in deep space.
Due to the different designs of the early spacecraft, the American and Soviet space programs also define an EVA differently. Russians define an EVA as occurring when a cosmonaut is in a vacuum. An American EVA begins when the astronaut switches the Extravehicular Mobility Unit (EMU) to battery power. A "Stand-up" EVA (SEVA) is where the astronaut does not fully exit a spacecraft, but is completely reliant on the spacesuit for environmental support. Its name derives from the astronaut "standing up" in the open hatch, usually to film or assist a spacewalking astronaut.
EVAs may be either tethered (the astronaut is connected to the spacecraft, oxygen can be supplied through a tube, no propulsion is needed to return to the spacecraft) or untethered. When the tether performs life support functions such as providing oxygen, it is called an umbilical. Untethered spacewalks were only performed on three missions in 1984 using the Manned Maneuvering Unit (MMU), and on a flight test in 1994 of the Simplified Aid for EVA Rescue (SAFER). A SAFER is a safety device worn on tethered U.S. EVAs, since the capability of returning to the spacecraft is essential.
As of 2009[update], Russia, the United States, and China are the only countries with a demonstrated capability to conduct an EVA.
For more information about Extra-vehicular activity, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with spacewalk
Stuck bolt, dead battery bedevil Hubble repairs
Space & Earth / Space Exploration
May 17, 2009 |
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(AP) -- Spacewalkers' specially designed tools couldn't dislodge a balky bolt interfering with repairs Sunday at the Hubble Space Telescope, so they took an approach more familiar to people puttering around ...
Let there be light: Camera hooked up for Hubble
Space & Earth / Space Exploration
May 14, 2009 |
5 / 5 (9) |
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(AP) -- A pair of spacewalking astronauts overpowered a stubborn bolt and successfully installed a new piano-sized camera in the Hubble Space Telescope on Thursday, the first step to making the observatory ...
Servicing Mission 4 -- the fifth and final visit to Hubble
Space & Earth / Space Exploration
May 01, 2009 |
4.8 / 5 (8) |
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(PhysOrg.com) -- The combination of Hubble's powerful suite of instruments and its position far above the effects of Earth's atmosphere has consistently produced outstanding scientific results for nineteen ...
Space station's new solar wings open easily (Update 2)
Space & Earth / Space Exploration
Mar 20, 2009 |
4.7 / 5 (3) |
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(AP) -- Astronauts successfully unfurled the newly installed solar wings at the international space station Friday, a nerve-racking procedure that went exceedingly well and brought the orbiting outpost to ...
Baby can wait as expectant dad finishes spacewalk
Space & Earth / Space Exploration
Nov 21, 2009 |
3.7 / 5 (3) |
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(AP) -- A spacewalking astronaut put aside the impending birth of his daughter and blazed through his first-ever venture outside the International Space Station on Saturday.
Astronauts get extra work done in 1st spacewalk (Update)
Space & Earth / Space Exploration
Nov 19, 2009 |
not rated yet |
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(AP) -- A pair of spacewalking astronauts, one of them a surgeon, hustled through antenna and cable work outside the International Space Station on Thursday and even whipped off an extra chore.
Astronauts take mission's 3rd and final spacewalk
Space & Earth / Space Exploration
Sep 06, 2009 |
3 / 5 (1) |
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(AP) -- Two spacewalking astronauts took on cable and antenna work at the international space station Saturday in their final trek outside, but encountered last-minute difficulty with a connector and had ...
Spacewalk performed despite approaching space junk
Space & Earth / Space Exploration
Sep 03, 2009 |
4.5 / 5 (2) |
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(AP) -- Two astronauts stepped out on a spacewalk to install a new tank of space station coolant Thursday as a large piece of orbiting junk headed their way.
NASA analyzing junk that could threaten astronauts
Space & Earth / Space Exploration
Sep 02, 2009 |
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(AP) -- A piece of space junk was drifting toward the shuttle-station complex and its 13 astronauts Wednesday, though NASA officials said the threat would not delay an upcoming spacewalk.
Spacewalkers tackle hefty tank removal in orbit
Space & Earth / Space Exploration
Sep 01, 2009 |
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(AP) -- A pair of spacewalkers successfully tackled a hefty tank removal job at the international space station Tuesday as their crewmates unloaded comedian Stephen Colbert's namesake treadmill for all "those ...
NASA delays shuttle Discovery launch
Space & Earth / Space Exploration
Aug 27, 2009 |
5 / 5 (1) |
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NASA on Thursday delayed the launch of the space shuttle Discovery until 0359 GMT Saturday so mission specialists could review tests on a faulty valve, the US space agency said.
Astronauts speed through 5th and final spacewalk
Space & Earth / Space Exploration
Jul 27, 2009 |
5 / 5 (2) |
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(AP) -- Astronauts completed the last spacewalk of their shared shuttle and station mission Monday, breezing through some rewiring, camera setups and other outdoor chores.
NASA patches air-purifying system on space station
Space & Earth / Space Exploration
Jul 26, 2009 |
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(AP) -- A space station air purifier was working again Sunday after it shut down at the worst possible time, when company was still visiting and had swollen the on-board crowd to a record 13.
Astronauts install fresh batteries on spacewalk 4
Space & Earth / Space Exploration
Jul 24, 2009 |
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(AP) -- Astronauts outfitted the international space station with fresh batteries in an extra-long spacewalk Friday, moving slowly to avoid a repeat of the suit trouble that cut short the previous outing.
Astronauts cut spacewalk short due to suit trouble (Update)
Space & Earth / Space Exploration
Jul 22, 2009 |
3 / 5 (1) |
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(AP) -- Two astronauts cut short their spacewalk and hurried back to the safety of the international space station on Wednesday after a suit problem resulted in rising carbon dioxide levels for one of the ...
