Human spaceflight facts for kids

Human spaceflight is when people travel into space aboard a spacecraft. Sometimes, the people on board control the ship themselves. Other times, the spacecraft is controlled from Earth or flies on its own.

People who train for space travel are called astronauts (in America and other places), cosmonauts (in Russia), or taikonauts (in China). People who are not professional astronauts but go to space are called space travelers.

The first person in space was Yuri Gagarin from the Soviet Union. He launched on April 12, 1961. This was the start of the Space Race. On May 5, 1961, Alan Shepard became the first American in space. Between 1968 and 1972, humans traveled to the Moon nine times with the United States' Apollo program. Since November 2, 2000, people have lived continuously in space on the International Space Station (ISS).

On October 15, 2003, Yang Liwei became the first Chinese taikonaut in space. This was China's first human spaceflight. As of March 2025, humans have not traveled beyond low Earth orbit since the Apollo 17 mission in December 1972.

Today, the United States, Russia, and China are the only countries with programs that can send humans into space. Many private companies are also working on their own space programs. These might be for space tourism or for doing science in space. The first private human spaceflight was a short trip on SpaceShipOne on June 21, 2004. The first private company to send a crew to orbit was SpaceX in May 2020. They took NASA astronauts to the ISS.

Exploring Space with People

How We Got Here: A History of Spaceflight

The Space Race: USA vs. USSR

Human spaceflight began during the Cold War. This was a time of tension between the United States and the Soviet Union (USSR). Both nations built powerful rockets to carry nuclear weapons. These rockets were also big enough to launch the first artificial satellites into space.

After the Soviet Union launched the first satellites in 1957 and 1958, the US started Project Mercury. Their goal was to send people into orbit. The USSR was secretly working on the Vostok program for the same goal. They launched the first human into space, Yuri Gagarin, on April 12, 1961. Gagarin orbited Earth once aboard Vostok 1.

On May 5, 1961, the US launched its first astronaut, Alan Shepard. He made a short suborbital flight on Freedom 7. Unlike Gagarin, Shepard controlled his spacecraft himself. On February 20, 1962, John Glenn became the first American to orbit Earth. The USSR sent five more cosmonauts in Vostok capsules. This included the first woman in space, Valentina Tereshkova, on June 16, 1963.

In 1961, US President John F. Kennedy set a big goal. He wanted to land a person on the Moon and bring them back safely by the end of the 1960s. The US started the Apollo program to send three-person capsules to the Moon. In 1962, the US also started Project Gemini. This program flew 10 missions with two-person crews in 1965 and 1966. Gemini helped the US gain experience for the Moon mission.

The USSR tried to keep up by changing their Vostok capsule into a two or three-person Voskhod capsule. They launched two flights in 1964 and 1965. They also achieved the first spacewalk, done by Alexei Leonov on March 8, 1965. However, the Voskhod program ended because it could not move around in orbit like Gemini. The US Gemini flights did many spacewalks. They also showed that humans could stay in space for two weeks. They performed the first space rendezvous and docking of spacecraft.

The US built the powerful Saturn V rocket for the Apollo missions. In December 1968, Frank Borman, James Lovell, and William Anders orbited the Moon ten times on Apollo 8. In 1969, Apollo 11 achieved Kennedy's goal. Neil Armstrong and Buzz Aldrin landed on the Moon on July 21. They returned safely on July 24 with pilot Michael Collins. By 1972, six Apollo missions had landed 12 men on the Moon. Half of them drove electric vehicles on the surface. The crew of Apollo 13 survived a problem in space. They flew around the Moon without landing and returned safely.

During this time, the USSR secretly worked on their own Moon programs. They developed the three-person Soyuz spacecraft. But they failed to build the large N1 rocket needed for a human Moon landing. They stopped their Moon programs in 1974. After losing the Moon race, they focused on building space stations. They used the Soyuz to carry cosmonauts to and from these stations. They started with the Salyut stations from 1971 to 1986.

After the Moon Landings

After the Apollo program, the US planned new space missions. They wanted a Space Transportation System with a reusable Space Shuttle. This shuttle would have wings and fly back to a runway. They also planned a permanent space station and trips to Mars. However, the US President, Richard Nixon, knew Congress would not pay for all these big plans. So, only the Space Shuttle was approved. The Shuttle's design was changed to make it cheaper and faster to build. It would use two reusable solid rocket boosters and a large, disposable fuel tank. The Shuttle would land without power, like a glider.

In 1973, the US launched the Skylab space station. Three crews lived there for 171 days, traveling on an Apollo spacecraft. During this time, US President Richard Nixon and Soviet leader Leonid Brezhnev worked to reduce Cold War tensions. They agreed on the Apollo–Soyuz program. In 1975, an Apollo spacecraft connected with Soyuz 19 in space. The American and Soviet crews shook hands. This flight was a symbol of cooperation.

The two nations still competed in space. The US developed the Space Shuttle and planned a space station called Freedom. The USSR launched three Almaz military stations, disguised as Salyuts, from 1973 to 1977. Then they built Mir, the first modular, semi-permanent space station. Mir was built from 1986 to 1996. It orbited about 354 kilometers (220 miles) high. Mir was used for 4,592 days and was safely brought down in 2001.

The Space Shuttle started flying in 1981. A fleet of four shuttles was built: Columbia, Challenger, Discovery, and Atlantis. A fifth shuttle, Endeavour, was built after Challenger was destroyed in an accident during launch on January 28, 1986. All seven astronauts died. From 1983 to 1998, twenty-two Shuttle flights carried parts for a European space station called Spacelab.

The USSR also built a reusable space shuttle called Buran. It was designed to launch on the Energia rocket. Buran could fly and land on its own. Unlike the US Space Shuttle, Buran did not have main rocket engines. It used smaller engines to get into orbit. Only one uncrewed test flight happened in November 1988. The program was canceled because of a lack of money and the end of the Soviet Union in 1991. The Buran that flew was later destroyed when its hangar roof collapsed in 2002.

Working Together in Space

The end of the Soviet Union in 1991 led to real cooperation between the US and Russia. Russia took over the Soviet Soyuz and Mir programs. The Shuttle-Mir Program involved American Space Shuttles visiting the Mir space station. Russian cosmonauts flew on the Shuttle, and an American astronaut lived on Mir for a long time.

In 1993, US President Bill Clinton worked with Russia to change the planned Space Station Freedom into the International Space Station (ISS). Building the station began in 1998. The ISS orbits about 409 kilometers (254 miles) high. Many Space Shuttle flights helped build, supply, and crew the ISS. Russia has built half of the ISS and continues to work with the US.

China Joins the Space Race

China became the third nation to send humans into space, after the USSR and US. During the Space Race, Mao Zedong and Zhou Enlai decided in 1967 that China should also have a crewed space program. This secret plan, Project 714, aimed to put two people in space by 1973. Nineteen pilots were chosen. The Shuguang-1 spacecraft was designed to carry two crew members. But the program was canceled in 1972 due to money problems.

In 1992, China started a new, successful crewed spaceflight program called "Project 921". China developed the Shenzhou spacecraft and the Long March 2F rocket for human spaceflight. They also built a new launch site and flight control center. The first uncrewed spacecraft, Shenzhou 1, launched on November 20, 1999. It returned the next day. This was a big step for China's space program. Three more uncrewed missions tested key technologies. On October 15, 2003, Shenzhou 5 carried Yang Liwei into orbit for 21 hours. He returned safely to Inner Mongolia. This made China the third nation to send a human into orbit on its own.

The next goal for China was to master extravehicular activities (EVAs, or spacewalks) and docking in space. On September 25, 2008, during the Shenzhou 7 flight, Zhai Zhigang and Liu Boming completed China's first EVA. In 2011, China launched the Tiangong 1 target spacecraft and the Shenzhou 8 uncrewed spacecraft. They connected automatically on November 3, 2011. About nine months later, Tiangong 1 connected manually with Shenzhou 9, which carried China's first female astronaut, Liu Yang.

In September 2016, Tiangong 2 was launched. It was a space laboratory with more advanced features. A month later, Shenzhou 11 docked with Tiangong 2. Two astronauts stayed in Tiangong 2 for about 30 days. This showed that astronauts could live in space for a medium amount of time. In April 2017, China's first cargo spacecraft, Tianzhou 1, docked with Tiangong 2. It completed tests for refueling in orbit. This marked the end of the second phase of China's space program.

The third phase began in 2020. The goal is to build China's own space station, Tiangong. The first part of Tiangong, the Tianhe core module, launched on April 29, 2021. It was launched by China's most powerful rocket, Long March 5B. Many cargo and crewed spacecraft have visited it. This shows China can support astronauts living in space for a long time.

China plans to finish building the Tiangong Space Station by the end of 2022. After that, Tiangong will be used for science and development for at least 10 years.

Other Countries' Space Dreams

The European Space Agency started developing the Hermes shuttle in 1987. It was meant to dock with the European Columbus space station. Both projects were canceled in 1992 because they were too expensive and could not meet their goals. No Hermes shuttles were ever built. The Columbus space station was later changed to become the European module on the International Space Station.

Japan (NASDA) began developing the HOPE-X experimental shuttle in the 1980s. It was to be launched on its H-IIA rocket. But problems in 1998 led to less funding. The project was canceled in 2003. Japan decided to join the International Space Station program instead. They contributed the Kibō Japanese Experiment Module and H-II Transfer Vehicle cargo spacecraft.

The "Space Shuttle Gap"

The US government planned to stop the Space Shuttle program. They wanted to replace it with a way to fly beyond low Earth orbit. However, these plans were canceled in 2011 because they were too expensive and behind schedule. As part of the Artemis program, NASA is now developing the Orion spacecraft. It will be launched by the Space Launch System.

NASA also relies on private companies to send astronauts to low Earth orbit. Examples include SpaceX Dragon 2, the Boeing Starliner, or Sierra Nevada Corporation's Dream Chaser. The time between the Space Shuttle's retirement in 2011 and the first launch of SpaceShipTwo in December 2018 is called the U.S. human spaceflight gap.

Private Companies Go to Space

Since the early 2000s, many private spaceflight companies have started. As of November 2024, SpaceX and Boeing have sent humans to orbit. Blue Origin has launched 8 crewed flights, with six crossing the Kármán line (the edge of space). Virgin Galactic has also launched crews on short suborbital trips. These companies plan to fly regular people for space tourism.

SpaceX developed Crew Dragon, which flies on the Falcon 9 rocket. It first launched astronauts to the ISS in May 2020. This was part of NASA's Commercial Crew Development program. The capsule can also fly other customers. The first tourist mission, Inspiration4, launched in September 2021.

Boeing developed the Starliner capsule for NASA's Commercial Crew program. It launches on a United Launch Alliance Atlas V rocket. Starliner had an uncrewed flight in December 2019. A second uncrewed flight was in May 2022. A crewed flight to fully test Starliner launched in June 2024.

Virgin Galactic is developing SpaceshipTwo. This commercial spacecraft is for short suborbital trips for space tourism. It reached space in December 2018.

Blue Origin is testing its New Shepard vehicle. As of September 2021, it had 16 uncrewed test flights. Its first crewed flight was on July 20, 2021. It carried founder Jeff Bezos, his brother Mark Bezos, aviator Wally Funk, and 18-year-old Oliver Daemen.

Space Travel for Everyone?

Many ideas for spacecraft that carry many passengers have been suggested. These "spaceliners" would take many people to destinations in space. Or they could fly people quickly between two places on Earth, using suborbital spaceflights. So far, none of these large concepts have been built. But some vehicles that carry fewer than 10 people are being tested.

One large spaceliner idea is the SpaceX Starship. SpaceX suggests it could carry over 100 people on Earth-to-Earth trips in under an hour.

Smaller spaceplanes or capsules for short suborbital trips have been developed. Virgin Galactic has the SpaceShipTwo spaceplane. Blue Origin has the New Shepard capsule. Both would take about six passengers into space for a short time of zero gravity. Then they would return to the launch site.

Who Gets to Go to Space?

Who gets to go to space has been a question since space exploration began. International space law says space is the "province of all mankind." But some criticize that space is not truly shared by everyone. Also, women and people of color have not always been included. Groups like the Justspace Alliance and Inclusive Astronomy are working to make spaceflight more open to everyone.

Women in Space: Breaking Barriers

The first woman in space was Valentina Tereshkova in 1963. But it was not until the 1980s that another woman flew in space. For a long time, all astronauts had to be military test pilots. Women could not have this job, which is why there was a delay. After the rules changed, Svetlana Savitskaya became the second woman in space. She was also from the Soviet Union. Sally Ride became the first American woman in space. Since then, women astronauts from eleven other countries have flown. The first spacewalk with only women happened in 2018. It was done by Christina Koch and Jessica Meir. The first mission to the Moon with a woman on board is planned for 2024.

Even with these steps, women are still not as common among astronauts. More than 600 people have flown in space, but only 75 have been women. Some issues that limit women in space programs include:

• Agencies sometimes limit women to half as much time in space as men. This is because they think women might be at greater risk for cancer.
• There is a lack of space suits that are the right size for female astronauts.

Amazing Space Achievements

Firsts in Space

• Yuri Gagarin was the first human in space and the first to orbit Earth.
• Either Robert M. White or Joseph A. Walker was the first to pilot a spaceplane, the North American X-15.
• Alexei Leonov was the first to walk in space.
• Walter M. Schirra and Tom Stafford were the first to perform a space rendezvous. They flew their Gemini 6A spacecraft close to Gemini 7.
• Neil Armstrong and David Scott were the first to rendezvous and dock. They connected their Gemini 8 spacecraft with an uncrewed vehicle.
• Frank Borman, Jim Lovell, and William Anders were the first to travel beyond low Earth orbit. They were also the first to orbit the Moon on Apollo 8.
• Apollo 10 reached the fastest speed ever traveled by a human: 39,897 km/h (24,791 mph).
• Neil Armstrong and Buzz Aldrin were the first to land on the Moon during Apollo 11.
• The crew of Apollo 13 flew the farthest from Earth for a crewed spacecraft: 400,171 kilometers (248,655 miles).
• Valeri Polyakov completed the longest single spaceflight, lasting over 437 days. Oleg Kononenko has spent the most total time in space on many missions, over 1,110 days.
• The International Space Station has had people living in space continuously since November 2, 2000.

Space Heroes from Around the World

• Yuri Gagarin became the first Soviet and first human in space.
• Alan Shepard became the first American in space.
• John Glenn became the first American to orbit Earth.
• Valentina Tereshkova became the first woman in space and to orbit Earth.
• Vladimír Remek from Czechoslovakia became the first non-American and non-Soviet in space.
• Rakesh Sharma became the first Indian citizen to orbit Earth.
• Svetlana Savitskaya became the first woman to walk in space.
• Yang Liwei became the first Chinese person in space and to orbit Earth.
• Christina Koch and Jessica Meir did the first spacewalk with only women.

Sally Ride became the first American woman in space in 1983. Eileen Collins was the first female Space Shuttle pilot. In 1999, she became the first woman to command a US spacecraft.

For many years, only astronauts from the USSR (later Russia) and the United States flew in space. This changed with Vladimir Remek's flight in 1978. As of 2010, people from 38 nations have flown in space. This includes space tourists.

Countries and Companies in Space

Human spaceflight programs have been run by the Soviet Union–Russian Federation, the United States, Mainland China, and American private spaceflight companies.

Who is Flying Now?

Here are the space vehicles and launch sites currently used for human spaceflights:

• Soyuz program/spacecraft (Russia): Launched from Baikonur Cosmodrome. The first crewed flight was in 1967. As of March 2025, there have been 153 crewed flights.
• China Manned Space Program/Shenzhou spacecraft (China): Launched from Jiuquan Satellite Launch Center. The first crewed flight was in 2003. As of March 2025, there have been 14 crewed orbital flights.
• SpaceX Crew Dragon (US): Launched from Kennedy Space Center Launch Complex 39A or Cape Canaveral Space Launch Complex 40. The first crewed flight was in 2020. As of March 2025, there have been 16 crewed orbital flights.
• New Shepard (US): Launched from Corn Ranch spaceport. The first crewed flight was in 2021. As of March 2025, there have been ten crewed suborbital flights.
• Boeing Starliner (US): Launched from Cape Canaveral Space Launch Complex 41. The first crewed launch was in 2024. As of March 2025, there has been 1 crewed orbital launch.

The following space stations are currently in Earth orbit for people to live in:

• International Space Station (US, Russia, Europe, Japan, Canada): Built in orbit. It orbits about 409 kilometers (254 miles) high. Crews travel there by Soyuz or Crew Dragon spacecraft.
• Tiangong Space Station (China): Built in orbit. Crews travel there by Shenzhou spacecraft.

Most of the time, the only humans in space are those on the ISS (usually 7 people) and on Tiangong (usually 3 people).

NASA and ESA use the term "human spaceflight." They used to say "manned space missions," but now they use gender-neutral language.

Future Space Missions

India is planning to send humans into space with its Gaganyaan vehicle. It was planned for 2022 but is now delayed to 2024. The Indian Space Research Organisation (ISRO) started this project in 2006. The goal is to send two or three crew members to low Earth orbit for 3 to 7 days. They will return safely for a water landing. In 2019, ISRO announced plans for an Indian Space Station by 2030. After that, they plan a crewed mission to the Moon.

The Japan Aerospace Exploration Agency has been developing a crewed spacecraft based on its H-II Transfer Vehicle cargo ship.

NASA is planning to land humans on Mars by the 2030s. The first step was Artemis I in 2022. It sent an uncrewed Orion spacecraft around the Moon and back.

SpaceX is developing Starship. This is a fully reusable two-stage system. It can be used for missions near Earth and to the Moon. The final goal is to land on Mars. A special version of Starship is being developed for the Artemis program.

Other countries and space agencies have also announced human spaceflight programs. These include Japan (JAXA), Iran (ISA), and North Korea (NADA).

Nations That Tried to Reach Space

This table lists nations that have tried to create their own human spaceflight programs. It does not include countries whose citizens have flown in space on another country's or private company's spacecraft.

Nation/Organization	Space agency	Name for space traveler	First launched astronaut	Date	Spacecraft	Launcher	Type
Union of Soviet Socialist Republics (1922–1991)	Soviet space program	cosmonaut	Yuri Gagarin	April 12, 1961	Vostok spacecraft	Vostok	Orbital
United States	National Aeronautics and Space Administration (NASA)	astronaut	Alan Shepard (suborbital)	May 5, 1961	Mercury spacecraft	Redstone	Suborbital
United States	National Aeronautics and Space Administration (NASA)	astronaut	John Glenn (orbital)	February 20, 1962	Mercury spacecraft	Atlas LV-3B	Orbital
People's Republic of China	Space program of the People's Republic of China	taikonaut	—	1973 (abandoned)	Shuguang	Long March 2A	Orbital
People's Republic of China	Space program of the People's Republic of China	taikonaut	—	1981 (abandoned)	Piloted FSW	Long March 2	Orbital
European Space Agency	CNES / European Space Agency (ESA)	astronaut	—	1992 (abandoned)	Hermes	Ariane V	Orbital
Russia	Roscosmos	cosmonaut	Alexander Viktorenko, Alexander Kaleri	March 17, 1992	Soyuz TM-14 to MIR	Soyuz-U2	Orbital
People's Republic of China	China Manned Space Agency (CMSA)	taikonaut	Yang Liwei	October 15, 2003	Shenzhou spacecraft	Long March 2F	Orbital
India	Indian Space Research Organisation (ISRO)	Vyomanaut	—	2024 (planned)	Gaganyaan	LVM 3	Orbital

Staying Safe in Space

There are two main dangers in spaceflight. One is the harsh space environment. The other is if equipment breaks down. Space agencies like NASA work hard to solve these problems. This is very important for long missions to places like Mars.

Dangers from Space Itself

Keeping Astronauts Alive

Astronauts need breathable air and drinkable water. The spacecraft's life support system provides these basic needs.

Health in Space

If a medical emergency happens, astronauts cannot quickly return to Earth. They also cannot easily get medical supplies or doctors. They might have to rely on limited resources and advice from Earth for a long time.

Spaceflight can cause problems like blindness and bone loss. In 2012, a study said spaceflight might harm astronauts' brains. It could also speed up Alzheimer's disease. In 2015, a report listed health dangers for a human mission to Mars.

In 2017, scientists found that astronauts' brains changed after space trips. Longer trips caused bigger brain changes. In 2018, researchers found bacteria on the International Space Station. They said these germs should be watched to keep astronauts healthy. In 2019, NASA reported that hidden viruses in humans might become active during space missions. This could add more risk to future deep-space missions.

In September 2021, an alarm went off on the SpaceX Dragon 2 during the Inspiration4 mission. It was caused by a toilet problem.

Living in Zero Gravity

Astronauts in low Earth orbit for a long time face several health issues from zero gravity. These include losing bone density and muscle strength. They can also have trouble with balance and less fitness. Over time, these effects can make it harder for astronauts to do their jobs or increase their risk of injury.

In zero gravity, astronauts do not use their back or leg muscles much. This makes the muscles weaken and shrink. Astronauts can lose up to 20% of their muscle mass on flights lasting 5 to 11 days. This loss of strength could be a serious problem in an emergency landing. After long spaceflights, astronauts are much weaker. They are not allowed to drive a car for 21 days.

Astronauts in zero gravity often feel confused and get motion sickness. They lose their sense of direction as their bodies adjust. When they return to Earth, they have to readjust. They might have trouble standing, focusing their eyes, walking, and turning. These problems get worse the longer they are in zero gravity. This can affect their ability to do tasks for landing or emergencies.

Also, after long space missions, male astronauts might have serious eyesight problems. This is a big concern for future deep space missions, like a trip to Mars. Long space flights can also change how a space traveler's eyes move.

Space Radiation: A Hidden Danger

Without good shielding, crews on missions beyond low Earth orbit are at risk from high-energy particles. These come from solar particle events (SPEs) linked to solar flares. A solar storm like the powerful Carrington Event could cause acute radiation sickness or even death in a poorly shielded spacecraft. Another strong solar storm happened in August 1972, after Apollo 16 landed and before Apollo 17 launched. This storm could have caused severe radiation sickness or even death for astronauts outside Earth's protective magnetic field.

Another type of radiation, galactic cosmic rays, also poses challenges for human spaceflight beyond low Earth orbit.

There is also concern that long spaceflight might weaken the body's ability to fight diseases. This could lead to a weaker immune system and activate hidden viruses. Radiation can harm the stem cells in bone marrow that make blood and immune cells. Because spacecraft are small, a weak immune system and active viruses can quickly spread infection.

Being Alone in Space

During long missions, astronauts are isolated in small spaces. Depression, anxiety, and other mental problems can happen more often than for an average person. These issues could affect the crew's safety and mission success. NASA spends a lot of money on mental health support for astronauts. So far, there is no way to fully prevent or reduce mental problems from long stays in space.

These mental issues can make it harder for astronauts to work. Sometimes, they are brought back to Earth early, which costs a lot of money. In 1976, a Russian space expedition returned to Earth. The cosmonauts reported a strong smell and feared a fluid leak. But after checking, there was no leak. NASA concluded the cosmonauts likely imagined the smell.

Changes in sensory systems during long space travel might affect astronauts' mental health.

How Space Affects Your Senses

Astronauts are in an extreme environment during spaceflight. Little changes happen around them. This can weaken the sensory input to their seven senses.

• Hearing – In space, there are no outside noises because sound waves cannot travel. Astronauts can talk to each other, but their voices become very familiar. Mechanical noises also become familiar.
• Sight – In zero gravity, body fluids move differently. An astronaut's face swells and presses on their eyes, which can affect their vision. The view outside the spacecraft is constant, which gives less visual stimulation. Astronauts might see flashes from cosmic rays, even with their eyes closed.
• Smell – The space station has a constant smell, like gunpowder. In zero gravity, fluids rise to the face and prevent the sinuses from drying. This dulls the sense of smell.
• Taste – The sense of taste is linked to smell. So, when smell is dulled, taste is too. Astronauts' food is often bland, and there is little variety. New food only arrives every few months.
• Touch – There are almost no new physical sensations. There is also little human physical contact during the journey.
• The vestibular system (motion and balance) – In zero gravity, all movements change. This extreme change can harm the vestibular system.
• The proprioception system (sense of body position and movement effort) – Because of zero gravity, there is less force on muscles. This means less stimulation for this system.

Dangers from Spacecraft and Gear

Spaceflight needs much higher speeds than travel on Earth. This means using powerful fuels for launch. It also means getting rid of a lot of energy, usually as heat, for a safe return through Earth's atmosphere.

Blasting Off Safely

Rockets can catch fire or explode. So, space capsules usually have a way to escape during launch. This is often a rocket on top of the capsule that pulls it away quickly. This was used on Mercury, Apollo, and Soyuz capsules. Or, it can be ejection seats that shoot astronauts out of the capsule for parachute landings. This was used on Vostok and Gemini.

An escape system is not always practical for spacecraft with many crew members, especially spaceplanes. The Vostok capsule had one seat and an ejection seat. When it was changed to the 2 or 3-person Voskhod, the ejection seat could not be used. No other escape system was added. The two Voskhod flights in 1964 and 1965 had no launch problems. The Space Shuttle had ejection seats for its pilot and copilot on early flights. But these could not be used for passengers sitting below the cockpit, so they were removed.

There have been only two in-flight launch aborts with a crew. The first was on Soyuz 18a on April 5, 1975. The rocket went off course, but the crew managed to separate the spacecraft and landed safely. The second was on October 11, 2018, with Soyuz MS-10. Both crew members survived again.

The first time a launch escape system was used on the launchpad, before a crewed flight, was on September 26, 1983. This was for the planned Soyuz T-10a launch. A fire started in the rocket 90 seconds before liftoff. Both cosmonauts escaped safely.

The only crew deaths during launch happened on January 28, 1986. The Space Shuttle Challenger broke apart 73 seconds after liftoff. A seal on a solid rocket booster failed, causing the fuel tank to explode. All seven crew members died.

Spacewalk Safety

Tasks outside a spacecraft need a space suit. Even with the risk of problems while working in open space, no one has died during a spacewalk. Spacewalking astronauts are usually attached to the spacecraft with tethers.

Coming Home Safely

The pilot of Soyuz 1, Vladimir Komarov, died on April 24, 1967. His capsule's parachutes failed during an emergency landing, causing the capsule to crash.

On February 1, 2003, all seven crew members on the Space Shuttle Columbia died during reentry. A heat shield on the wing was damaged during launch by a piece of foam from the fuel tank. Hot gases entered and destroyed the wing, causing the shuttle to break apart.

The Air Inside the Spaceship

There are two main choices for the air inside a spacecraft. One is an Earth-like mix of oxygen and a gas like nitrogen. The other is pure oxygen, which can be used at lower pressure. The International Space Station and Soyuz spacecraft use a nitrogen–oxygen mix. Space suits for extravehicular activity often use low-pressure pure oxygen.

Using a gas mixture can cause decompression sickness (the bends) when changing to or from the pure oxygen space suit. There have been injuries and deaths from too much nitrogen and not enough oxygen.

• In 1960, a test pilot was seriously injured when nitrogen-rich air leaked into his space suit. This led NASA to use a pure oxygen atmosphere for Mercury, Gemini, and Apollo spacecraft.
• In 1981, three workers died from nitrogen-rich air in the Space Shuttle's engine area.
• In 1995, two workers died from a nitrogen leak at a rocket launch pad.

A pure oxygen atmosphere has a risk of fire. The original Apollo spacecraft used pure oxygen at high pressure before launch. An electrical fire started in the Apollo 1 cabin during a ground test on January 27, 1967. The fire spread quickly. The high pressure, made worse by the fire, prevented the hatch from opening in time. All three astronauts—Gus Grissom, Ed White, and Roger Chaffee—died. After this, NASA used a nitrogen–oxygen atmosphere before launch and only low-pressure pure oxygen in space.

When Things Go Wrong

The March 1966 Gemini 8 mission was stopped in orbit. A thruster got stuck on, causing the spacecraft to spin dangerously. This threatened the lives of Neil Armstrong and David Scott. Armstrong had to turn off the control system and use the reentry system to stop the spin. The spacecraft made an emergency landing, and the astronauts were safe. The problem was likely an electrical short. The control system was changed to put each thruster on its own separate circuit.

The third Moon landing mission, Apollo 13, in April 1970, was also stopped. The lives of the crew—James Lovell, Jack Swigert, and Fred Haise—were in danger. A cryogenic liquid oxygen tank failed on the way to the Moon. The tank burst, losing all its oxygen and damaging a second tank. This caused a loss of electrical power to the spacecraft. The crew managed to return to Earth safely by using the lunar landing craft as a "lifeboat." The tank failed because of two mistakes: the tank was damaged during factory testing, and the heaters inside had faulty wiring.

The crew of Soyuz 11 died on June 30, 1971. They suffocated because the cabin lost pressure. A valve opened when explosive bolts fired to separate parts of the spacecraft. The loss of pressure became deadly in about 30 seconds.

Sad Moments in Space History

As of December 2015, 23 crew members have died in accidents aboard spacecraft. Over 100 others have died in accidents related to spaceflight or testing.

Date	Mission	Accident cause	Deaths	Cause of death
January 27, 1967	Apollo 1	Electrical fire in the cabin during a test. The fire spread quickly due to pure oxygen and flammable materials. High pressure prevented the hatch from opening.	3	Cardiac arrest from carbon monoxide poisoning
April 24, 1967	Soyuz 1	Main parachute failed, and the reserve parachute got tangled. The spacecraft crashed.	1	Trauma from crash landing
November 15, 1967	X-15 Flight 3-65-97	Pilot lost control of the X-15 due to distraction and misreading instruments.	1	Vehicle broke apart
June 30, 1971	Soyuz 11	Cabin lost pressure when a valve opened too early during separation.	3	Suffocation
January 28, 1986	STS-51L Space Shuttle Challenger	A seal failed in a solid rocket booster in cold weather. Hot gases burned through the fuel tank, causing an explosion. The shuttle broke apart.	7	Suffocation or trauma from impact
February 1, 2003	STS-107 Space Shuttle Columbia	Heat shield on the wing was damaged during launch. Hot gases entered during reentry, destroying the wing and causing the shuttle to break apart.	7	Suffocation or trauma as the shuttle broke apart
October 31, 2014	SpaceShipTwo VSS Enterprise powered drop-test	Copilot made a mistake, deploying the air-braking system too early. The vehicle broke apart in flight.	1	Trauma from crash

Images for kids

• 

  Apollo 11 astronaut Buzz Aldrin on the Moon, 1969

• 

  Voskhod 2 cosmonaut Alexei Leonov, first in open space, 1965

• 

  Gemini 4 astronaut Ed White in open space, 1965

• 

  Japan Aerospace Exploration Agency astronaut Akihiko Hoshide taking a space selfie in 2012

• 

  International Space Station crewmember Tracy Caldwell Dyson views the Earth, 2010