Extravehicular activity

Extravehicular activity

Extravehicular activity, often called a spacewalk, is any work an astronaut does in outer space outside of a spacecraft. This can include walking on the lunar surface or a planet, standing up in the open door of a spacecraft, or moving around in space while connected to the spacecraft. Many countries have done spacewalks, including the Soviet Union/Russia, the United States, and China. Astronauts from Canada, Japan, the United Arab Emirates, and the European Space Agency have also joined in.

The very first spacewalk was done by Alexei Leonov on March 18, 1965, during the Voskhod 2 mission. It lasted about 12 minutes. Later, on July 20, 1969, Neil Armstrong became the first person to walk on the Moon during the Apollo 11 mission. In 1984, Svetlana Savitskaya was the first woman to do a spacewalk. Spacewalks can be done in different ways. Sometimes astronauts stay connected to their spacecraft with a special cord for air and power. Other times, they move around without being tied down, using special tools to stay safe.

Development history

NASA planners created the term extravehicular activity (EVA) in the early 1960s for the Apollo program to land humans on the Moon. Astronauts would leave the spacecraft to collect lunar material samples and set up scientific tools. To help with this, the Gemini program was started to let astronauts work outside a small spacecraft orbiting Earth. Meanwhile, the Soviet Union wanted to stay ahead in space travel, so they changed their Vostok capsule into a bigger craft called Voskhod.

The Voskhod needed air to cool its tools, so an airlock was used for astronauts to go out and come back in safely. The Gemini spacecraft did not need this cooling. Because of these differences, the American and Soviet space programs had different ways of measuring how long an EVA lasted. The Soviet way started when the outer airlock door opened. An American EVA started when the astronaut had at least their head outside the spacecraft. The U.S. later changed its definition.

The first EVA happened on March 18, 1965, when Soviet cosmonaut Alexei Leonov spent 12 minutes outside the Voskhod 2 spacecraft. He carried a backpack with oxygen but had no way to control his movement except pulling on a rope. After the walk, he said it was easy, but his suit puffed up in space, making it hard to move. When he tried to get back in, he got stuck and had to lower the pressure in his suit. It took almost four years before the Soviets tried another EVA.

The first American spacewalk was done by Ed White on June 3, 1965, from the Gemini IV spacecraft. He stayed outside for 21 minutes, tied to the spacecraft, and used a special tool to move around. However, there was a problem with the spacecraft's door that made it hard to open and close.

More EVAs were planned for later Gemini missions, but some had to be canceled because of problems with the spacecraft. Astronauts on several Gemini flights did manage to do EVAs, but they often got tired and too hot. On November 13, 1966, Edwin "Buzz" Aldrin became the first to work outside without getting tired during Gemini XII. He spent over two hours outside. Aldrin’s experience with scuba diving helped him think of ways to practice for spacewalks underwater, a method still used today.

On January 16, 1969, Soviet cosmonauts Aleksei Yeliseyev and Yevgeny Khrunov moved from one spacecraft to another that were connected together. This was the second Soviet EVA, and it would be almost nine years before they did another one.

American astronauts Neil Armstrong and Buzz Aldrin did the first EVA on the Moon's surface on July 21, 1969, after landing their Apollo 11 spacecraft. This first Moon walk lasted 2 hours and 36 minutes. Fifteen Moon walks were done by six Apollo crews. Eugene Cernan was the last Apollo astronaut to step on the Moon.

The first EVA repairs of a spacecraft were done by astronauts on the Skylab 2 mission in 1973. They fixed parts of the Skylab space station that were damaged when it launched. After Skylab, the United States did not do any EVAs until the Space Shuttle program began in the early 1980s. During this time, the Soviets continued with EVAs on their Salyut 6 and Salyut 7 space stations.

When the United States started doing EVAs again in 1983, astronauts began using a special suit called an Extravehicular Mobility Unit for life support. Many EVAs were done during the building of the ISS.

China became the third country to do an EVA on September 27, 2008, during the Shenzhou 7 mission. Chinese astronaut Zhai Zhigang did a 22-minute spacewalk, with help from Liu Boming. Since 2021, China has done several more EVAs to build the Tiangong space station.

American company SpaceX did the first private EVA on September 12, 2024. Entrepreneur Jared Isaacman and SpaceX engineer Sarah Gillis briefly went outside a spacecraft for testing tools. SpaceX plans to do more missions with EVAs in the future, including one with their Starship spacecraft.

Milestones

Capability milestones

The first time an astronaut walked in space without being tied to a spacecraft was done by American Bruce McCandless II on February 7, 1984, during the Space Shuttle Challenger mission STS-41-B. He used a special moving unit and was later joined by Robert L. Stewart for a spacewalk that lasted almost six hours.

Soviet cosmonauts Svetlana Savitskaya and Vladimir Dzhanibekov did the first metalwork in space on July 25, 1984, using special tools during a spacewalk outside the Salyut 7 space station.

On May 13, 1992, three astronauts—Pierre Thuot, Richard Hieb, and Thomas Akers—worked together outside the spacecraft to fix a broken satellite. This was the only time three people have done a spacewalk together.

American Steve Robinson did an important repair on August 3, 2005, during the mission STS-114. He removed some loose material from Discovery’s heat shield to keep it safe when it returned to Earth.

The longest spacewalk ever was done by Cai Xuzhe and Song Lingdong on December 17, 2024, lasting over nine hours. Before that, the record was held by U.S. astronauts James Voss and Susan Helms.

Personal cumulative duration records

Russian Anatoly Solovyev has spent the most time walking in space, with 16 spacewalks totaling over 82 hours.

Michael Lopez-Alegria holds the American record with 10 spacewalks totaling almost 68 hours.

Thomas Pesquet holds the record for astronauts from Europe or other countries, with 6 spacewalks totaling almost 40 hours.

Sunita Williams has spent the most time walking in space for a woman, with over 62 hours. Peggy Whitson has done the most spacewalks for a woman, with 10 spacewalks.

National, race and sex firsts

The first woman to walk in space was Soviet Svetlana Savitskaya on July 25, 1984, spending over three hours outside the Salyut 7 space station.

The first American woman to walk in space was Kathryn D. Sullivan on October 11, 1984.

The first time two women walked in space together was on October 18, 2019, when Christina Koch and Jessica Meir did a spacewalk during Expedition 61 on the International Space Station.

The first woman from Asia and China to walk in space was Wang Yaping on November 8, 2021, outside the Chinese Tiangong space station.

The first Native American woman to walk in space was Nicole Aunapu Mann on January 20, 2023, during Expedition 68 on the International Space Station.

The first spacewalk by someone not from the Soviet Union or the United States was done by Jean-Loup Chrétien of France on December 9, 1988.

The first spacewalk by a Black African-American was done by Bernard A. Harris Jr on February 9, 1995.

The first Japanese astronaut to walk in space was Takao Doi on November 25, 1997.

The first Swiss astronaut to walk in space was Claude Nicollier on December 23, 1999.

The first Australian-born person to walk in space was Andy Thomas on March 13, 2001.

The first Canadian astronaut to walk in space was Chris Hadfield on April 22, 2001, along with NASA astronaut Scott Parazynski.

The first Swedish astronaut to walk in space was Christer Fuglesang on December 12, 2006.

The first Chinese astronaut to walk in space was Zhai Zhigang on September 27, 2008, making China the third country to do so.

The first Italian astronaut to walk in space was Luca Parmitano on July 9, 2013, with NASA astronaut Chris Cassidy.

The first British astronaut to walk in space was Tim Peake on January 15, 2016.

The first Arab astronaut to walk in space was Sultan Al Neyadi on April 28, 2023.

Commemoration

The first spacewalk was done by Soviet cosmonaut Alexei Leonov in 1965. Some countries made stamps to honor this event. Because not many details were shared about the Voskhod spacecraft, the spaceship on the stamps was not real.

The U.S. Post Office made a stamp in 1967 to celebrate Ed White's first American spacewalk. The stamp shows the Gemini IV spacecraft and White's space suit.

Designations

During the Space Shuttle program, astronauts who went on spacewalks were given special names. These names were like EV-1, EV-2, EV-3, and EV-4. They helped to identify each astronaut on their mission.

Camp-out procedure

For spacewalks from the International Space Station, NASA used a special camp-out procedure to help astronauts stay safe. Astronauts sleep overnight in the airlock before going outside. The air pressure is lowered to help remove nitrogen from the body. Now, astronauts often use a different method.