Extravehicular Activity

Extravehicular Activity
Name	Extravehicular Activity

Extravehicular Activity is the performance of tasks by astronauts or cosmonauts outside a pressurized spacecraft, station, or habitat in space and in planetary environments. It encompasses spacewalks, lunar sorties, and surface excursions conducted by crews from programs such as NASA, Roscosmos, European Space Agency, JAXA, and CSA. EVAs support operations on platforms like International Space Station, Mir, Skylab, and lunar missions tied to Apollo program and future Artemis program endeavors.

Overview

EVAs enable maintenance, assembly, scientific research, and exploration on platforms including Hubble Space Telescope, ISS Destiny Laboratory, Zarya module, and Harmony (ISS module). Common participants originate from agencies such as NASA, Roscosmos, ESA, JAXA, and CSA, with crews from nations like United States, Russia, Japan, Canada, Italy, Germany, France and United Kingdom. Programs that specialize in EVAs include Apollo program, Space Shuttle program, Shenzhou program, Soyuz (spacecraft), and commercial ventures like SpaceX Crew Dragon and Boeing Starliner. Major technologies cross-linked with EVA practice include systems developed at organizations such as Jet Propulsion Laboratory, Johnson Space Center, Goddard Space Flight Center, and Marshall Space Flight Center.

History

Early conceptual work traces to pioneers tied to Konstantin Tsiolkovsky, Sergey Korolev, and the Soviet space program; practical achievement came with Alexei Leonov performing the first spacewalk during Voskhod 2 and Ed White executing a U.S. spacewalk on Gemini 4. Subsequent milestones include EVAs on Skylab by crews connected to Pete Conrad, Paul J. Weitz, and Jerry L. Carr and assembly EVAs during the Space Shuttle program by astronauts such as John Young, Robert L. Crippen, Bruce McCandless II, and Kathryn D. Sullivan on missions like STS-41-B and STS-31. Construction and maintenance on International Space Station involved long-duration EVAs by Yuri Gagarin Cosmonaut Training Center graduates and international crewmembers including Sergei Krikalev, Scott Kelly, Chris Hadfield, Samantha Cristoforetti, Tim Peake, Peggy Whitson, and Sunita Williams. Lunar EVAs on Apollo 11, Apollo 12, Apollo 14, Apollo 15, Apollo 16, and Apollo 17 featured astronauts like Neil Armstrong, Buzz Aldrin, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charlie Duke, Gene Cernan, and Harrison Schmitt. More recent EVAs have supported servicing of Hubble Space Telescope by teams led by Kathryn Thornton, Michael Lopez-Alegria, and John Grunsfeld, and assembly EVAs enabling modules like Zvezda (ISS module), Columbus (ISS module), and Kibo (ISS module).

Equipment and Suits

EVA suits and hardware evolved from garments such as the Extravehicular Mobility Unit used by NASA to the Orlan (spacesuit) series used by Roscosmos. Key suit components and subsystems were developed by contractors and labs including Hamilton Standard, ILC Dover, Energia, RKK Energia, European Astronaut Centre, and Mitsubishi Heavy Industries. Life-support backpacks like the Portable Life Support System connect to communications and telemetry managed via Mission Control Center facilities such as Johnson Space Center and TsUP (Mission Control Center). Airlock systems for EVA operations include designs for Apollo Lunar Module, Space Shuttle airlock, Quest Joint Airlock, Pirs (ISS module), Poisk (ISS module), and future concepts for Orion (spacecraft) and Gateway (spacecraft). Tools and restraints used during EVAs have included specialized hardware from suppliers collaborating with programs at Kennedy Space Center, Stennis Space Center, Marshall Space Flight Center, and European partners like Thales Alenia Space and Airbus Defence and Space.

Procedures and Safety

EVA procedures are governed by mission rules established by operational centers such as Mission Control Center, MCC-Houston, TsUP, ESA Mission Control Centre, and JAXA Tsukuba Space Center. Pre-breathing protocols, prebreathe cycles, and contingency plans reference standards developed after incidents investigated by entities like National Transportation Safety Board and internal boards led by officials from NASA and Roscosmos. Training occurs in facilities including Neutral Buoyancy Laboratory, Hydrolab, European Astronaut Centre, and at centrifuge and parabolic flight sites like Boeing Wichita contractors and Air Force Flight Test Center collaborators. Safety technologies incorporate tethers, Simplified Aid For EVA Rescue, redundant life-support, and emergency procedures coordinated with platforms such as Space Shuttle Atlantis (OV-104), Soyuz MS, Shenzhou variants, and commercial vehicles like Crew Dragon Endeavour.

Scientific and Operational Roles

EVAs enable scientific sampling and emplacement tasks for programs like Apollo program geology traverses led with scientists such as Harrison Schmitt and geologists affiliated with Smithsonian Institution and USGS. On International Space Station, EVAs support experiments in facilities like Columbus Laboratory, Kibo Experiment Logistics Module, and Microgravity Science Glovebox, and cooperations with investigators from Caltech, MIT, Stanford University, Imperial College London, and CNES. Operational roles include installation and repair of observatories such as Hubble Space Telescope, deployment of payloads from Space Shuttle Columbia (OV-102), and assembly tasks for modules flown on Atlantis (OV-104), Endeavour (OV-105), and Discovery (OV-103). EVAs also prepare infrastructure for exploration architectures involving Artemis program, Lunar Gateway, Constellation Program, and proposals by commercial firms including SpaceX, Blue Origin, and Sierra Nevada Corporation.

Records and Notable EVAs

Notable EVAs include the first by Alexei Leonov on Voskhod 2, the first American EVA by Ed White on Gemini 4, the historic lunar surface EVAs of Apollo 11 with Neil Armstrong and Buzz Aldrin, and extensive servicing missions to Hubble Space Telescope by crews such as John Grunsfeld and Michael Foale. Long-duration and cumulative EVA records involve astronauts like Anatoly Solovyev, Michael Lopez-Alegria, Peggy Whitson, Oleg Artemyev, Kjell Lindgren, and Sunita Williams. Landmark assembly EVAs for International Space Station included work by Sergei Krikalev, Michael Foale, William Shepherd, Shannon Lucid, and Scott Parazynski. Emergency and high-profile EVA rescues and repairs invoked responses coordinated across agencies including NASA, Roscosmos, ESA, and commercial partners during missions such as STS-49, STS-88, and ISS contingency operations.

Category:Human spaceflight