The station suffered from two major problems, the first of which required extensive repair work to be performed on a number of EVAs.

After the Space Shuttle Challenger disaster, the MMU was judged too risky for further use and it was found many activities planned for the MMU could be done effectively with manipulator arms or traditional tethered EVAs.

In future Gemini EVAs, the work loads of the astronauts were reduced, but it was clear that during lunar exploration workloads could be significant and changes were made to ensure that the Apollo EVA suit would be water cooled.

Destinations for EVAs can be chosen from an established waypoint database and traveled to either on foot or by ATV.

During this mission, the crew conducted the initial test flight of Endeavour, performed a record four EVAs ( space walks ) to retrieve, repair and re-deploy the International Telecommunications Satellite ( INTELSAT ) and to demonstrate and evaluate numerous EVA tasks to be used for the assembly of the Space Station ' Freedom '.

Rick Sturckow, who would be choreographing the EVAs from inside the shuttle, joined Ross and Newman to check out the SAFER units to be worn during the spacewalks in case Ross or Newman were to become separated from Endeavour during one of the spacewalks.

Because the J-series CSMs incorporated the Scientific Instrument Module ( SIM ) Bay, which used special film cameras similar to those used on Air Force spy satellites, and required a " deep space " EVA for retrieval, the CMP for each of the three J-series missions wore a five-connector A7LB based H-series A7L suits, with the liquid cooling connections eliminated as the CMP would be attached to a life-support umbilical ( like that used on Gemini EVAs ) and only an " oxygen purge system " ( OPS ) would be used, along with a " red apple " lanyard, for emergency backup in the case of the failure of the umbilical.

During one of the EVAs, a small rod from within the spacesuit punctured the seal of one of the astronauts ' gloves ( the name is undisclosed, but it was either Ross or Apt ).

A SAFER is a safety device worn on tethered U. S. EVAs, since the capability of returning to the spacecraft is essential.

The capture required three EVAs: a planned one by astronaut Thuot and Hieb who were unable to attach a capture bar to the satellite from a position on the RMS ; a second unscheduled but identical attempt the following day ; and finally an unscheduled but successful hand capture by Thuot, Hieb and Akers as commander Brandenstein delicately maneuvered the orbiter to within a few feet of the 4215 kg communications satellite.

He was a co-investigator on the M-509 astronaut maneuvering unit experiment which was flown in the Skylab Program, and collaborated on the development of the Manned Maneuvering Unit ( MMU ) used during Shuttle EVAs.

For EVAs on board the ISS, the astronaut must pre-breathe for about four hours.

The new suit would have been designed, depending upon the configration, to protect the astronaut during launch, in-flight emergencies, reentry and landing, and both microgravity and lunar EVAs.

During his 179 days aboard Mir, he carried out two EVAs and became the first German astronaut to perform a spacewalk.

* Robert Curbeam became the first astronaut to make four EVAs during the same mission.

He is known for having performed ten EVAs so far in his career, presently holding the second longest all-time EVA duration record and having the longest spaceflight of any American at the length of 215 days ; this time was spent on board the ISS from September 18, 2006 to April 21, 2007.

On each of the last three of these missions, astronauts also performed deep-space EVAs on the return to Earth, to retrieve film canisters from the outside of the spacecraft.

Astronauts on the next three Gemini flights ( Eugene Cernan, Michael Collins and Richard Gordon ), performed several EVAs, but none was able to successfully work for long periods outside the spacecraft without tiring and overheating.

Aldrin worked outside the spacecraft for 2 hours and 6 minutes, in addition to two stand-up EVAs in the spacecraft hatch for an additional 3 hours and 24 minutes.

When the United States resumed EVAs on April 7, 1983, astronauts started using an Extravehicular Mobility Unit ( EMU ) for self-contained life support independent of the spacecraft.

His first spaceflight was Gemini 10, in which he and command pilot John Young performed two rendezvous with different spacecraft and Collins undertook two EVAs.

These EVAs represented man's first untethered operations from a spacecraft in flight.

Because of the short duration of those EVAs, and as a need to protect the delicate instruments, the Apollo lunar EVA backpack was replaced with a Gemini-style umbilical assembly, except that it was modified to incorporate both breathing air ( Skylab's atmosphere was 80 % oxygen and 20 % nitrogen at 5 psi ) and liquid water for cooling.

Two crewmembers performed a series of three space walks to connect electrical umbilicals and to attach hardware to the exterior structure for use during future EVAs.

The crew of STS-109 successfully upgraded the Hubble Space Telescope ’ s systems over the course of five consecutive EVAs, leaving it with a new power control unit, improved solar arrays, the new Advanced Camera for Surveys ( ACS ), and an experimental refrigeration unit for cooling the dormant Near Infrared Camera and Multi-Object Spectrometer ( NICMOS ).

After Skylab, no more EVAs were made by the United States until the advent of the Space Shuttle program in the early 1980s.

The damage was eventually repaired by Leonid Kizim and Vladimir Solovyov, who after four EVAs managed to fix two leaks but needed a special tool to fix the third.

The STS 41-B mission marked the first checkout of the Manned Maneuvering Unit ( MMU ), and Manipulator Foot Restraint ( MFR ), with Bruce McCandless II and Bob Stewart performing two spectacular EVAs ( space walks ).

The mission also included flight testing of Manned Maneuvering Units ( MMUs ) in two extravehicular activities ( EVAs ), and operation of the Cinema 360 and IMAX Camera Systems.

The mission goals were to conduct experiments using the United States Microgravity Payload ( USMP-4 ), to conduct 2 EVAs, and to deploy the SPARTAN-201 experiment.

Other EVAs followed on the Shuttle, notably those on STS-41-B ( the first Manned Maneuvering Unit flight ), STS-41-C ( the Solar Max repair mission ), and STS-51-A ( where two stranded satellites were retrieved and returned to Earth ), but the majority of EMU uses occurred on the servicing missions of the Hubble Space Telescope.

Before these four extravehicular activities ( EVAs ), 52 spacewalks had been performed at the ISS, with 27 based out of the Station.

During this mission, Scott became the last American to fly solo in Earth orbit ( not counting subsequent untethered EVAs ).

No EVAs were planned on the next three Gemini flights.

The Skylab 2 crew made three EVAs, and a total of ten EVAs were made by the three Skylab crews.

In this period, the Soviets resumed EVAs, making four from the Salyut 6 and Salyut 7 space stations between December 20, 1977, and July 30, 1982.

USOS modules were brought to the station by the Space Shuttle and manually attached to the ISS by crews during EVAs.

Their three-day mission called for them to rendezvous with two different Agena Target Vehicles, undertake two EVAs, and perform fifteen different experiments.

In an EVA to reinforce a torn solar panel during STS-120, a pair of pliers was lost and during STS-126, Heidemarie Stefanyshyn-Piper lost a briefcase-sized tool bag in one of the mission's EVAs.

While on the Moon during Apollo 17, he and his crewmate Harrison Schmitt performed three EVAs for a total of about 22 hours of exploration.

Since this was a J-Mission, it meant that they would spend more time on the moon than previous missions, to allow for three EVAs.

Duke served as Lunar Module pilot of Apollo 16 in 1972 where he and John W. Young landed at the Descartes Highlands and conducted three EVAs, making Duke the tenth person to walk upon the surface of the Moon.