Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA includes spacewalks and lunar or planetary surface exploration. In a stand-up EVA (SEVA), an astronaut stands through an open hatch but does not fully leave the spacecraft. EVAs have been conducted by the Soviet Union/Russia, the United States, Canada, the European Space Agency and China.
A space suit is an environmental suit used for protection from the harsh environment of outer space, mainly from its vacuum as a highly specialized pressure suit, but also its temperature extremes, as well as radiation and micrometeoroids. Basic space suits are worn as a safety precaution inside spacecrafts in case of loss of cabin pressure. For extravehicular activity (EVA) more complex space suits are worn, featuring a portable life support system.
Buzz Aldrin is an American former astronaut, engineer and fighter pilot. He made three spacewalks as pilot of the 1966 Gemini 12 mission, and was the Lunar Module Eagle pilot on the 1969 Apollo 11 mission. He was the second person to walk on the Moon after mission commander Neil Armstrong. Following the death of Michael Collins in 2021, he is the last surviving Apollo 11 crew member.
The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight in Houston, Texas, where human spaceflight training, research, and flight control are conducted. It was renamed in honor of the late U.S. president and Texas native, Lyndon B. Johnson, by an act of the United States Senate on February 19, 1973.
Gemini 9A was a 1966 crewed spaceflight in NASA's Gemini program. It was the seventh crewed Gemini flight, the 15th crewed American flight and the 23rd spaceflight of all time. The original crew for Gemini 9, command pilot Elliot See and pilot Charles Bassett, were killed in a crash on February 28, 1966, while flying a T-38 jet trainer to the McDonnell Aircraft plant in St. Louis, Missouri to inspect their spacecraft. Their deaths promoted the backup crew, Thomas P. Stafford and Eugene Cernan, to the prime crew. The mission was renamed Gemini 9A after the original May 17 launch was scrubbed when the mission's Agena Target Vehicle was destroyed after a launch failure. The mission was flown June 3–6, 1966, after launch of the backup Augmented Target Docking Adaptor (ATDA). Stafford and Cernan rendezvoused with the ATDA, but were unable to dock with it because the nose fairing had failed to eject from the docking target due to a launch preparation error. Cernan performed a two-hour extravehicular activity, during which it was planned for him to demonstrate free flight in a self-contained rocket pack, the USAF Astronaut Maneuvering Unit. He was unable to accomplish this due to stress, fatigue, and overheating.
Gemini 12 was a 1966 crewed spaceflight in NASA's Project Gemini. It was the 10th and final crewed Gemini flight, the 18th crewed American spaceflight, and the 26th spaceflight of all time, including X-15 flights over 100 kilometers (54 nmi). Commanded by Gemini VII veteran James A. Lovell, the flight featured three periods of extravehicular activity (EVA) by rookie Edwin "Buzz" Aldrin, lasting a total of 5 hours and 30 minutes. It also achieved the fifth rendezvous and fourth docking with an Agena target vehicle.
A reduced-gravity aircraft is a type of fixed-wing aircraft that provides brief near-weightless environments for training astronauts, conducting research, and making gravity-free movie shots.
Project Gemini was the second United States human spaceflight program to fly. Conducted after the first American crewed space program, Project Mercury, while the Apollo program was still in early development, Gemini was conceived in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966.
Zero Gravity Corporation is an American company based in Exploration Park, Florida, formerly of Fort Lauderdale, Florida, which operates weightless flights from United States airports. Zero-G is governed under Part 121 of FAA regulations enabling the company to cater to both tourists and researchers alike. Zero-G is operated by Everts Air Cargo who holds the 121 certificate.
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of reference, as opposed to the force experienced in linear acceleration, which by the equivalence principle is indistinguishable from gravity. In a more general sense, "artificial gravity" may also refer to the effect of linear acceleration, e.g. by means of a rocket engine.
Neutral buoyancy occurs when an object's average density is equal to the density of the fluid in which it is immersed, resulting in the buoyant force balancing the force of gravity that would otherwise cause the object to sink or rise. An object that has neutral buoyancy will neither sink nor rise.
The Space Systems Laboratory (SSL) is part of the Aerospace Engineering Department and A. James Clark School of Engineering at the University of Maryland in College Park, Maryland. The Space Systems Laboratory is centered on the Neutral Buoyancy Research Facility, a 50-foot-diameter (15 m), 25-foot-deep (7.6 m) neutral buoyancy pool used to simulate the microgravity environment of space. The only such facility housed at a university, Maryland's neutral buoyancy tank is used for undergraduate and graduate research at the Space Systems Lab. Research in Space Systems emphasizes space robotics, human factors, applications of artificial intelligence and the underlying fundamentals of space simulation. There are currently five robots being tested, including Ranger, a four-armed satellite servicing robot, and SCAMP, a six-degree of freedom free-flying underwater camera platform. Ranger was funded by NASA starting in 1992, and was to be a technological demonstration of orbital satellite servicing. NASA was never able to manifest it for launch and the program was defunded circa 2006. For example, Ranger development work at the SSL continues, albeit at a slower pace; Ranger was used to demonstrate robotic servicing techniques for NASA's proposed robotic Hubble Servicing Mission.
The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility, near the Johnson Space Center in Houston, Texas. The NBL's main feature is a large indoor pool of water, in which astronauts may perform simulated EVA tasks in preparation for upcoming missions. Trainees wear suits designed to provide neutral buoyancy to simulate the microgravity that astronauts experience during spaceflight.
The Experimental Assembly of Structures in EVA and the Assembly Concept for Construction of Erectable Space Structures, or EASE/ACCESS, were a pair of space shuttle flight experiments that were performed on STS-61-B, on November 29 and December 1, 1985. The purpose of the experiments was to study how quickly astronauts would become proficient at assembling space structures during extravehicular activity, and how quickly they would become fatigued, and to explore various construction and maintenance techniques. In particular, researchers studied the applied moments of inertia arising in the manual assembly of a large space structure.
The Neutral Buoyancy Simulator was a neutral buoyancy pool located at NASA's George C. Marshall Space Flight Center (MSFC). Engineers and astronauts developed hardware and practiced procedures in this tank from its completion in 1968 through its decommissioning in 1997. Marshall recognized the need for underwater simulations of extra-vehicular activities (EVAs) and developed three successively larger tanks for the purpose. The Neutral Buoyancy Simulator contributed significantly to the American crewed space program. Skylab, the Space Shuttle, Hubble Space Telescope, and the International Space Station have all benefited from the Neutral Buoyancy Simulator. Until Johnson Space Center constructed the Weightless Environment Test Facility in the mid-1970s, MSFC had the only NASA-owned test facility that allowed engineers and astronauts to become familiar with the dynamics of body motion under weightless conditions.
Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g or, incorrectly, zero gravity.
Astronaut training describes the complex process of preparing astronauts in regions around the world for their space missions before, during and after the flight, which includes medical tests, physical training, extra-vehicular activity (EVA) training, wilderness survival training, water survival training, robotics training, procedure training, rehabilitation process, as well as training on experiments they will accomplish during their stay in space.
Terrestrial analogue sites are places on Earth with assumed past or present geological, environmental or biological conditions of a celestial body such as the Moon or Mars. Analogue sites are used in the frame of space exploration to either study geological or biological processes observed on other planets, or to prepare astronauts for surface extra-vehicular activity.
Hervé Stevenin is a European aquanaut leading ESA Neutral Buoyancy Facility Operations and the EVA Training Unit at the European Astronaut Centre (EAC) in Cologne, Germany. He served as an aquanaut on the NASA Extreme Environment Mission Operations 19 crew.
A neutral buoyancy pool or neutral buoyancy tank is a pool of water in which neutral buoyancy is used to train astronauts for extravehicular activity and the development of procedures. These pools began to be used in the 1960s and were initially just recreational swimming pools; dedicated facilities would later be built.
