Skylab in the context of "NASA"

A space station (or orbital station) is a spacecraft which remains in orbit and hosts humans for extended periods of time. It is therefore an artificial satellite featuring habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served military or commercial uses, such as hosting space tourists.

Space stations have been hosting the only continuous presence of humans in space. The first space station was Salyut 1 (1971), hosting the first crew, of the ill-fated Soyuz 11. Consecutively space stations have been operated since Skylab (1973) and occupied since 1987 with the Salyut successor Mir. Uninterrupted human presence in orbital space through space stations has been sustained since the operational transition from the Mir to the International Space Station (ISS), with the latter's first occupation in 2000.

The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight in Houston, Texas (originally named the Manned Spacecraft Center), 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.

JSC consists of a complex of 100 buildings constructed on 1,620 acres (660 ha) in Clear Lake. The center is home to NASA's astronaut corps, and is responsible for training astronauts from both the U.S. and its international partners. It also houses the Christopher C. Kraft Jr. Mission Control Center, which has provided the flight control function for every NASA human spaceflight since Gemini 4 (including Apollo, Skylab, Apollo–Soyuz, and Space Shuttle). It is popularly known by its radio call signs "Mission Control" and "Houston".

The Apollo/Skylab space suit (sometimes called the Apollo 11 Spacesuit because it was most known for being used in the Apollo 11 Mission) is a class of space suits used in Apollo and Skylab missions. The names for both the Apollo and Skylab space suits were Extravehicular Mobility Unit (EMU). The Apollo EMUs consisted of a Pressure Suit Assembly (PSA) aka "suit" and a Portable Life Support System (PLSS) that was more commonly called the "backpack". The A7L was the PSA model used on the Apollo 7 through 14 missions.

The subsequent Apollo 15-17 lunar missions, Skylab, and Apollo–Soyuz used A7LB pressure suits. Additionally, these pressure suits varied by program usage. For the Skylab EMU, NASA elected to use an umbilical life support system named the Astronaut Life Support Assembly.

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 (commonly known from 1969 to 1972 as moonwalks). 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, and China; astronauts from Canada, Japan, the United Arab Emirates, and the European Space Agency have also participated in EVAs conducted by those nations.

On March 18, 1965, Alexei Leonov became the first human to perform a spacewalk, exiting the Voskhod 2 capsule for 12 minutes and 9 seconds. On July 20, 1969, Neil Armstrong became the first human to perform a moonwalk, outside his lunar lander on Apollo 11 for 2 hours and 31 minutes. In 1984, Svetlana Savitskaya became the first woman to perform a spacewalk, conducting EVA outside the Salyut 7 space station for 3 hours and 35 minutes. On the last three Moon missions, astronauts also performed deep-space EVAs on the return to Earth, to retrieve film canisters from the outside of the spacecraft. American Astronauts Pete Conrad, Joseph Kerwin, and Paul Weitz also used EVA in 1973 to repair launch damage to Skylab, the United States' first space station.

A coronal hole is a region of the Sun's corona that appears dark in extreme-ultraviolet (EUV) and soft-X-ray images because its plasma is cooler and more rarefied than the surrounding corona. Despite its name, a coronal hole is not an actual physical hole or void in the Sun's corona. The darkness reveals open magnetic field lines that guide plasma directly into interplanetary space, producing the fast component of the solar wind. They are composed of relatively cool and tenuous plasma permeated by magnetic fields that are open to interplanetary space. This results in decreased temperature and density of the plasma at the site of a coronal hole, as well as an increased speed in the average solar wind measured in interplanetary space.

Coronal holes were first identified unambiguously in soft-X-ray images from the 1973 Skylab mission, although eclipse photographs had hinted at polar dark regions earlier in the twentieth century. Routine mapping now combines full-disk EUV imagers with ground-based synoptic magnetographs to track hole evolution and feed space-weather forecasts.

As part of the Apollo program by NASA, 24 astronauts flew nine missions to the Moon between December 1968 and December 1972. During six successful two-man landing missions, twelve men walked on the lunar surface, six of whom drove Lunar Roving Vehicles as part of the last three missions. Three men have been to the Moon twice, one orbited once and took a circumlunar trajectory the second time, while the other two landed once apiece. Apart from these 24 men, no human being has gone beyond low Earth orbit. As of December 2025, five of the 24 remain alive. A number of non-human animals have circled or orbited it, including two tortoises, several turtles, and five mice.

Apollo missions 8 and 10–17 were the nine crewed missions to the Moon. Apollo 4–6 and AS-201 and AS-202 were uncrewed, while AS-203 is considered a test flight. The Apollo program included three other crewed missions: Apollo 1 (AS-204) did not launch and its crew died in a ground-based capsule fire, while Apollo 7 and Apollo 9 were low Earth orbit missions that tested spacecraft components and docking maneuvers. Apollo missions 18, 19, and 20 were canceled. Twelve astronauts later flew unused Apollo command modules in the Apollo Applications Program's Skylab and Apollo–Soyuz Test Project. Of the 24 astronauts who flew to the Moon, two went on to command a Skylab mission, one commanded Apollo–Soyuz, one flew as commander for Approach and Landing Tests of the Space Shuttle, and two commanded orbital Space Shuttle missions.

Jack Robert Lousma (born February 29, 1936) is an American astronaut, aeronautical engineer, retired United States Marine Corps officer, former naval aviator, NASA astronaut, and politician. He was a member of the second crew, Skylab-3, on the Skylab space station in 1973. In 1982, he commanded STS-3, the third Space Shuttle mission. Lousma was inducted into the United States Astronaut Hall of Fame in 1997. He is the last living crew member of both of his spaceflights.

Lousma later was the Republican Party nominee for a seat in the United States Senate from Michigan in 1984, losing to incumbent Carl Levin, who won his second of six terms.