Human spaceflight

Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft. Spacecraft carrying people may be operated directly, by human crew, or it may be either remotely operated from ground stations on Earth or be autonomous, able to carry out a specific mission with no human involvement.

"Space traveler" redirects here. For other uses, see Space traveler (disambiguation).

Apollo 11 astronaut Buzz Aldrin on the Moon, 1969

Voskhod 2 astronaut 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

The first human in space was Yuri Gagarin, who flew the Vostok 1 spacecraft, launched by the Soviet Union on 12 April 1961 as part of the Vostok program. Humans have flown to the Moon nine times from 1968 to 1972 in the United States Apollo program, and have been continuously present in space for 19 years and 288 days on the International Space Station.[1]

Russia and China have human spaceflight capability with the Soyuz program and Shenzhou program. In the United States, SpaceShipTwo reached the edge of space in 2018; this was the first crewed spaceflight from the US since the Space Shuttle retired in 2011. From 2011 to May 2020 expeditions to the International Space Station used Soyuz vehicles, which remain attached to the station to allow quick return if needed. The United States developed commercial crew transportation to facilitate domestic access to the ISS, low Earth orbit and beyond such as the Orion vehicle and the private SpaceX Starship. The first successful commercial launch from the United States was conducted in May 2020 aboard the SpaceX Crew Dragon spacecraft carrying NASA astronauts Robert Behnken and Douglas Hurley on their way to the International Space Station.[2]

While spaceflight has typically been a government-directed activity, commercial spaceflight has gradually been taking on a greater role. The first private human spaceflight took place on 21 June 2004, when SpaceShipOne conducted a suborbital flight, and a number of non-governmental companies have been working to develop a space tourism industry. NASA has also played a role to stimulate private spaceflight through programs such as Commercial Orbital Transportation Services (COTS) and Commercial Crew Development (CCDev). With its 2011 budget proposals released in 2010,[3] the Obama administration moved towards a model where commercial companies would supply NASA with transportation services of both people and cargo transport to low Earth orbit. The vehicles used for these services could then serve both NASA and potential commercial customers. Commercial resupply of ISS began two years after the retirement of the Shuttle,[4] and commercial crew launches have operated since May 2020.[5]

History

Main article: History of spaceflight

Cold War era

Main article: Space Race

Replica of the Vostok space capsule, which carried the first human into orbit

Mercury space capsule, which carried the first Americans into orbit

North American X-15, hypersonic rocket-powered aircraft, which reached the edge of space

Neil Armstrong, the first human to land and walk on the Moon, July 1969.

Human spaceflight capability was first developed during the Cold War between the United States and the Soviet Union (USSR), which developed the first intercontinental ballistic missile rockets to deliver nuclear weapons. These rockets were large enough to be adapted to carry the first artificial satellites into low Earth orbit. After the first satellites were launched in 1957 and 1958, the US worked on Project Mercury to launch men singly into orbit, while the USSR secretly pursued the Vostok program to accomplish the same thing. The USSR launched the first human in space, Yuri Gagarin, into a single orbit in Vostok 1 on a Vostok 3KA rocket, on 12 April 1961. The US launched its first astronaut, Alan Shepard, on a suborbital flight aboard Freedom 7 on a Mercury-Redstone rocket, on 5 May 1961. Unlike Gagarin, Shepard manually controlled his spacecraft's attitude, and landed inside it. The first American in orbit was John Glenn aboard Friendship 7, launched 20 February 1962 on a Mercury-Atlas rocket. The USSR launched five more cosmonauts in Vostok capsules, including the first woman in space, Valentina Tereshkova aboard Vostok 6 on 16 June 1963. The US launched a total of two astronauts in suborbital flight and four into orbit through 1963. The US also made two flights in the North American X-15 (90 and 91) piloted by Joseph A. Walker that exceeded the Kármán line, the internationally recognized 100 km altitude used by the FAI to denote the edge of space.

US President John F. Kennedy raised the stakes of the Space Race by setting the goal of landing a man on the Moon and returning him safely by the end of the 1960s.[6] The US started the three-man Apollo program in 1961 to accomplish this, launched by the Saturn family of launch vehicles, and the interim two-man Project Gemini in 1962, which flew 10 missions launched by Titan II rockets in 1965 and 1966. Gemini's objective was to support Apollo by developing American orbital spaceflight experience and techniques to be used in the Moon mission.[7]

Meanwhile, the USSR remained silent about their intentions to send humans to the Moon, and proceeded to stretch the limits of their single-pilot Vostok capsule into a two- or three-person Voskhod capsule to compete with Gemini. They were able to launch two orbital flights in 1964 and 1965 and achieved the first spacewalk, made by Alexei Leonov on Voskhod 2 on 8 March 1965. But Voskhod did not have Gemini's capability to maneuver in orbit, and the program was terminated. The US Gemini flights did not accomplish the first spacewalk but overcame the early Soviet lead by performing several spacewalks and solving the problem of astronaut fatigue caused by overcoming the lack of gravity, demonstrating up to two weeks endurance in a human spaceflight, and the first space rendezvous and dockings of spacecraft.

The US succeeded in developing the Saturn V rocket necessary to send the Apollo spacecraft to the Moon, and sent Frank Borman, James Lovell, and William Anders into 10 orbits around the Moon in Apollo 8 in December 1968. In July 1969, Apollo 11 accomplished Kennedy's goal by landing Neil Armstrong and Buzz Aldrin on the Moon 21 July and returning them safely on 24 July along with Command Module pilot Michael Collins. A total of six Apollo missions landed 12 men to walk on the Moon through 1972, half of which drove electric powered vehicles on the surface. The crew of Apollo 13, Lovell, Jack Swigert, and Fred Haise, survived a catastrophic in-flight spacecraft failure and returned to Earth safely without landing on the Moon.

Soyuz, most serial spacecraft

Salyut 1, first manned space station, with docked Soyuz spacecraft

Meanwhile, the USSR secretly pursued crewed lunar orbiting and landing programs. They successfully developed the three-person Soyuz spacecraft for use in the lunar programs, but failed to develop the N1 rocket necessary for a human landing, and discontinued the lunar programs in 1974.[8] On losing the Moon race, they concentrated on the development of space stations, using the Soyuz as a ferry to take cosmonauts to and from the stations. They started with a series of Salyut sortie stations from 1971 to 1986.

Post-Apollo era

Artist's rendering of an Apollo CSM is about to dock with a Soyuz spacecraft.

After the Apollo program, the US launched the Skylab sortie space station in 1973, inhabiting it for 171 days with three crews aboard Apollo spacecraft. President Richard Nixon and Soviet Premier Leonid Brezhnev negotiated an easing of relations known as détente, an easing of Cold War tensions. As part of this, they negotiated the Apollo-Soyuz program, in which an Apollo spacecraft carrying a special docking adapter module rendezvoused and docked with Soyuz 19 in 1975. The American and Russian crews shook hands in space, but the purpose of the flight was purely diplomatic and symbolic.

Nixon appointed his Vice President Spiro Agnew to head a Space Task Group in 1969 to recommend follow-on human spaceflight programs after Apollo. The group proposed an ambitious Space Transportation System based on a reusable Space Shuttle which consisted of a winged, internally fueled orbiter stage burning liquid hydrogen, launched by a similar, but larger kerosene-fueled booster stage, each equipped with airbreathing jet engines for powered return to a runway at the Kennedy Space Center launch site. Other components of the system included a permanent modular space station, reusable space tug and nuclear interplanetary ferry, leading to a human expedition to Mars as early as 1986, or as late as 2000, depending on the level of funding allocated. However, Nixon knew the American political climate would not support Congressional funding for such an ambition, and killed proposals for all but the Shuttle, possibly to be followed by the space station. Plans for the Shuttle were scaled back to reduce development risk, cost, and time, replacing the piloted flyback booster with two reusable solid rocket boosters, and the smaller orbiter would use an expendable external propellant tank to feed its hydrogen-fueled main engines. The orbiter would have to make unpowered landings.

Space Shuttle orbiter, first crewed orbital spaceplane

The two nations continued to compete rather than cooperate in space, as the US turned to developing the Space Shuttle and planning the space station, dubbed Freedom. The USSR launched three Almaz military sortie stations from 1973 to 1977, disguised as Salyuts. They followed Salyut with the development of Mir, the first modular, semi-permanent space station, the construction of which took place from 1986 to 1996. Mir orbited at an altitude of 354 kilometers (191 nautical miles), at a 51.6° inclination. It was occupied for 4,592 days, and made a controlled reentry in 2001.

The Space Shuttle started flying in 1981, but the US Congress failed to approve sufficient funds to make Freedom a reality. A fleet of four shuttles was built: Columbia, Challenger, Discovery, and Atlantis. A fifth shuttle, Endeavour, was built to replace Challenger, which was destroyed in an accident during launch that killed 7 astronauts on 28 January 1986. Twenty-two Shuttle flights carried a European Space Agency sortie space station called Spacelab in the payload bay from 1983 to 1998.[9]

Buran-class orbiter, copy of the Space Shuttle orbiter

The USSR copied the reusable Space Shuttle orbiter, which they called Buran-class orbiter or simply Buran. It was designed to be launched into orbit by the expendable Energia rocket, and capable of robotic orbital flight and landing. Unlike the Space Shuttle, Buran had no main rocket engines, but like the Space Shuttle orbiter it used engines to perform its final orbital insertion. A single uncrewed orbital test flight was successfully made in November 1988. A second test flight was planned by 1993, but the program was canceled due to lack of funding and the dissolution of the Soviet Union in 1991. Two more orbiters were never completed, and the one that performed an uncrewed flight was destroyed in a hangar roof collapse in May 2002.

US / Russian cooperation

International Space Station, assembled in orbit by US and Russia

The dissolution of the Soviet Union in 1991 brought an end to the Cold War and opened the door to true cooperation between the US and Russia. The Soviet Soyuz and Mir programs were taken over by the Russian Federal Space Agency, now known as the Roscosmos State Corporation. The Shuttle-Mir Program included American Space Shuttles visiting the Mir space station, Russian cosmonauts flying on the Shuttle, and an American astronaut flying aboard a Soyuz spacecraft for long-duration expeditions aboard Mir.

In 1993, President Bill Clinton secured Russia's cooperation in converting the planned Space Station Freedom into the International Space Station (ISS). Construction of the station began in 1998. The station orbits at an altitude of 409 kilometers (221 nmi) and an inclination of 51.65°.

The Space Shuttle was retired in 2011 after 135 orbital flights, several of which helped assemble, supply, and crew the ISS. Columbia was destroyed in another accident during reentry, which killed 7 astronauts on 1 February 2003.

Russia has continued cooperation though half of the International Space Station is its sole singular half.

China

Shenzhou, first non-USSR and non-USA spacecraft

After Russia's launch of Sputnik 1 in 1957, Chairman Mao Zedong intended to place a Chinese satellite in orbit by 1959 to celebrate the 10th anniversary of the founding of the People's Republic of China (PRC),[10] However, China did not successfully launch its first satellite until 24 April 1970. Mao and Premier Zhou Enlai decided on 14 July 1967, that the PRC should not be left behind, and started China's own human spaceflight program.[11] The first attempt, the Shuguang spacecraft copied from the US Gemini, was cancelled on 13 May 1972.

China later designed the Shenzhou spacecraft resembling the Russian Soyuz, and became the third nation to achieve independent human spaceflight capability by launching Yang Liwei on a 21-hour flight aboard Shenzhou 5 on 15 October 2003. China launched the Tiangong-1 space station on 29 September 2011, and two sortie missions to it: Shenzhou 9 16–29 June 2012, with China's first female astronaut Liu Yang; and Shenzhou 10, 13–26 June 2013. The station was retired on 21 March 2016 and reentered on 2 April 2018, burning up with smaller fragments impacting the ocean. Tiangong-1's successor Tiangong-2 was launched in September 2016 to then be derorbited in July 2019. Tiangong-2 hosted a crew of two (Jing Haipeng and Chen Dong) for 26 days. The Tianzhou 1 cargo spacecraft docked to the station on 22 April 2017.

Abandoned programs of other nations

The European Space Agency began development in 1987 of the Hermes shuttle spaceplane, to be launched on the Ariane 5 expendable launch vehicle and to be docks with European Columbus space station. The projects were cancelled in 1992, when it became clear that neither cost nor performance goals could be achieved. No Hermes shuttles were ever built. Columbus space station reconfigured to same name European module in International Space Station.

Japan (NASDA) began development in the 1980s of the HOPE-X experimental shuttle spaceplane, to be launched on its H-IIA expendable launch vehicle. A string of failures in 1998 led to funding reduction, and the project's cancellation in 2003 in favour of participation in International Space Station by Kibō Japanese Experiment Module and H-II Transfer Vehicle cargo spacecraft.

As alternative to HOPE-X NASDA in 2001 proposed Fuji manned capsuled spacecraft for independent or ISS flights but project was no adopted.

Earlier in 1993-1997 Japanese Rocket Society, Kawasaki Heavy Industries and Mitsubishi Heavy Industries proposed Kankoh-maru proposed vertical takeoff and landing single-stage manned of cargo reusable launch system. Later in 2005 this system was proposed for space tourism.

According to a press-release of Iraqi News Agency of 5 December 1989 about the first (and last) test of the Tammouz space launcher, Iraq intended to develop crewed space facilities by the end of the century. These plans were put to an end by the Gulf War of 1991 and the economic hard times that followed.

United States "Shuttle gap"

STS-135 (July 2011), the final human spaceflight of the United States until 2020

Crew Dragon Demo-2 (May–August 2020), the first human spaceflight of the United States since STS-135

Under the Bush administration, the Constellation program included plans for retiring the Space Shuttle program and replacing it with the capability for spaceflight beyond low Earth orbit. In the 2011 United States federal budget, the Obama administration cancelled Constellation for being over budget and behind schedule while not innovating and investing in critical new technologies.[12] As part of the Artemis program, NASA is developing the Orion spacecraft to be launched by the Space Launch System. Under the Commercial Crew Development plan, NASA will rely on transportation services provided by the private sector to reach low Earth orbit, such as SpaceX Dragon 2, Sierra Nevada Corporation's Dream Chaser, or Boeing Starliner. The period between the retirement of the Space Shuttle in 2011 and the first launch to space of SpaceShipTwo Flight VP-03 on 13 December 2018 is similar to the gap between the end of Apollo in 1975 and the first Space Shuttle flight in 1981, is referred to by a presidential Blue Ribbon Committee as the U.S. human spaceflight gap.

SpaceX Dragon 2 launched on May 30, 2020 with a crew of 2 US astronauts, making it the first human spaceflight of the United States since STS-135.[13]

Commercial private spaceflight

SpaceShipOne, first private sub-orbital spaceplane

Crew Dragon, first private orbital spacecraft

Since the early 2000s, a variety of private spaceflight ventures have been undertaken. Several of the companies, including Blue Origin, SpaceX, Virgin Galactic, and Sierra Nevada have explicit plans to advance human spaceflight. As of 2016, all four of those companies have development programs underway to fly commercial passengers.

A commercial suborbital spacecraft aimed at the space tourism market is being developed by Virgin Galactic called SpaceshipTwo which reached space in December 2018.[14][15] Blue Origin has begun a multi-year test program of their New Shepard vehicle and carried out 11 successful uncrewed test flights in 2015–2019. Blue Origin planned to fly with humans in 2019.

SpaceX and Boeing are both developing passenger-capable orbital space capsules as of 2020, with SpaceX carrying NASA astronauts to the International Space Station onboard a Crew Dragon spacecraft launched on a Falcon 9 Block 5 launch vehicle. Boeing will be doing it with their CST-100 launched on a United Launch Alliance Atlas V launch vehicle.[16] Development funding for these orbital-capable technologies has been provided by a mix of government and private funds, with SpaceX providing a greater portion of total development funding for this human-carrying capability from private investment.[17][18] There have been no public announcements of commercial offerings for orbital flights from either company, although both companies are planning some flights with their own private, not NASA, astronauts on board.

Milestones

By achievement

12 April 1961

Yuri Gagarin was the first human in space and the first in Earth orbit, on Vostok 1 on 12 April 1961.

17 July 1962 or 19 July 1963

Either Robert M. White or Joseph A. Walker (depending on the definition of the space border) were first to pilot a spaceplane, the North American X-15, on 17 July 1962 (White) or 19 July 1963 (Walker).

18 March 1965

Alexei Leonov was first to walk in space, on 18 March 1965.

15 December 1965

Walter M. Schirra and Tom Stafford were first to perform a space rendezvous, piloting their Gemini 6A spacecraft and station-keeping one foot (30 cm) from Gemini 7 for over 5 hours.

16 March 1966

Neil Armstrong and David Scott were first to rendezvous and dock, piloting their Gemini 8 spacecraft to dock with an uncrewed Agena Target Vehicle.

December 1968

Frank Borman, Jim Lovell, and William Anders were first to travel beyond low Earth orbit (LEO) and first to orbit the Moon, on the Apollo 8 mission which orbited the Moon ten times before returning to Earth, from 21-27 Dec 1968.

20 July 1969

Neil Armstrong and Buzz Aldrin were first to land on the Moon, on 20 July 1969 during Apollo 11.

Longest time in space

Valeri Polyakov performed the longest single spaceflight, from 8 January 1994 to 22 March 1995 (437 days, 17 hours, 58 minutes, and 16 seconds). Gennady Padalka has spent the most total time in space on multiple missions, 879 days.

Longest crewed space station

The International Space Station has the longest period of continuous human presence in space, 2 November 2000 to present (19 years and 288 days). This record was previously held by Mir, from Soyuz TM-8 on 5 September 1989 to the Soyuz TM-29 on 28 August 1999, a span of 3,634 days (almost 10 years).

By nationality or sex

12 April 1961

Yuri Gagarin became the first Soviet as well as the first human to reach space on Vostok 1 on 12 April 1961.

5 May 1961

Alan Shepard became the first American to reach space on Freedom 7 on 5 May 1961.

20 February 1962

John Glenn became the first American to orbit the Earth on 20 February 1962.

16 June 1963

Valentina Tereshkova became the first woman to go into space and to orbit the Earth on 16 June 1963.

2 March 1978

Vladimír Remek, a Czechoslovakian, became the first non-American and non-Soviet in space on 2 March 1978.

2 April 1984

Rakesh Sharma, became the first Indian citizen to reach Earth's orbit on 2 April 1984.

25 July 1984

Svetlana Savitskaya became the first woman to walk in space on 25 July 1984.

15 October 2003

Yang Liwei became the first Chinese in space and the Earth's orbit on Shenzhou 5 on 15 October 2003.

18 October 2019

Christina Koch and Jessica Meir conduct the first woman-only walk in space.[19]

Sally Ride became the first American woman in space in 1983. Eileen Collins was the first female Shuttle pilot, and with Shuttle mission STS-93 in 1999 she became the first woman to command a U.S. spacecraft.

For many years, only the USSR (later Russia) and the United States had their own astronauts. Citizens of other nations flew in space, beginning with the flight of Vladimir Remek, a Czech, on a Soviet spacecraft on 2 March 1978, in the Interkosmos programme. As of 2010, citizens from 38 nations (including space tourists) have flown in space aboard Soviet, American, Russian, and Chinese spacecraft.

Space programs

"Astronaut corps" redirects here. For subdivision of NASA, see NASA Astronaut Corps.

Human spaceflight programs have been conducted by the former Soviet Union and currently Russia, the United States, Mainland China, and by the American private spaceflight companies.

  Currently have human spaceflight programs.

  Confirmed and dated plans for human spaceflight programs.

  Confirmed plans for human spaceflight programs.

  Plans for human spaceflight on the simplest form (suborbital spaceflight, etc.).

  Plans for human spaceflight on the extreme form (space stations, etc.).

  Once had official plans for human spaceflight programs, but have since been abandoned.

Current programs

Space vehicles are spacecraft used for transportation between the Earth's surface and outer space, or between locations in outer space. The following space vehicles and spaceports are currently used for launching human spaceflights:

• Soyuz program (USSR/Russia): spacecraft on Soyuz launch vehicle, from Baikonur Cosmodrome; 140 crewed orbital flights since 1967, including two in-flight aborts which failed to reach orbit, as of March 2019
• Shenzhou program (China): spacecraft on Long March launch vehicle, from Jiuquan Satellite Launch Center; 5 flights since 2003, as of July 2016
• Spaceshiptwo (US): Air launched from White knight two carrier aircraft. 2 suborbital spaceflights since 2018, as of February 2019
• Crew Dragon (US): Part of the Commercial Crew Program, launched from Kennedy Space Center on a Falcon 9 rocket. One successful launch with more in the planning stages.[20]

The following space stations are currently maintained in Earth orbit for human occupation:

• International Space Station (US and Russia) assembled in orbit: altitude 409 kilometers (221 nautical miles), 51.65° inclination; crews transported by Soyuz spacecraft

Numerous private companies attempted human spaceflight programs in an effort to win the $10 million Ansari X Prize. The first private human spaceflight took place on 21 June 2004, when SpaceShipOne conducted a suborbital flight. SpaceShipOne captured the prize on 4 October 2004, when it accomplished two consecutive flights within one week.

Most of the time, the only humans in space are those aboard the ISS, whose crew of six spends up to six months at a time in low Earth orbit.

NASA and ESA use the term "human spaceflight" to refer to their programs of launching people into space. These endeavors have also been referred to as "manned space missions," though because of gender specificity this is no longer official parlance according to NASA style guides.[21]

Planned future programs

Under the Indian Human Spaceflight Programme, India is planning to send humans into space on its orbital vehicle Gaganyaan before August 2022. The Indian Space Research Organisation (ISRO) began work on this project in 2006.[22][23] The initial objective is to carry a crew of two or three to low Earth orbit (LEO) for a 3 to 7 day flight in a spacecraft on a GSLV Mk III rocket and return them safely for a water landing at a predefined landing zone. On 15 August 2018, Indian Prime Minister Narendra Modi, from the rampart of the Red Fort in New Delhi, formally declared that India will independently send humans into space before the 75th anniversary of independence in 2022.[24] In 2019, ISRO further revealed plans for a space station by 2030, followed by a crewed lunar mission. Activities are currently progressing with a focus on the development of critical technologies, infrastructure and subsystems such as the crew module (CM), environmental control and life support system (ECLSS), crew escape system, etc. The department has initiated activities to study technical and managerial issues related to crewed missions. The program envisages the development of a fully autonomous orbital vehicle capable of carrying 2 or 3 crew members to an about 300 km (190 mi) low Earth orbit and bringing them safely back home. Development of space food and astronaut training is underway as of 2020, although the impact of the COVID-19 pandemic could delay the first mission by many months.[25]

NASA is developing a plan to land humans on Mars by the 2030s. The first step will begin with Artemis 1 in 2021, sending an uncrewed Orion spacecraft to a distant retrograde orbit around the Moon and return it to Earth after a 25-day mission.

Several other countries and space agencies have announced and begun human spaceflight programs utilizing natively developed equipment and technology, including Japan (JAXA), Iran (ISA) and North Korea (NADA).

Since 2008 Japan Aerospace Exploration Agency developes H-II Transfer Vehicle cargo spacecraft based manned spacecraft and Kibō Japanese Experiment Module based small space laboratory.

Iranian manned spaceship project suggests small spacecraft and space laboratory. North Korea's space program has manned spacecraft and small shuttle system even as final aims.

Passenger travel via spacecraft

A number of spacecraft have been proposed over the decades that might facilitate spaceliner passenger travel. Somewhat analogous to travel by airliner after the middle of the 20th century, these vehicles are proposed to transport a large number of passengers to destinations in space, or to destinations on Earth which travel through space. To date, none of these concepts have been built, although a few vehicles that carry fewer than 10 persons are currently in the flight testing phase of their development process.

One large spaceliner concept currently in early development is the SpaceX Starship which, in addition to replacing the Falcon 9 and Falcon Heavy launch vehicles in the legacy Earth-orbit market after 2020, has been proposed by SpaceX for long-distance commercial travel on Earth. This is to transport people on point-to-point suborbital flights between two points on Earth in under one hour, also known as "Earth-to-Earth," and carrying 100+ passengers.[26][27][28]

Small spaceplane or small capsule suborbital spacecraft have been under development for the past decade or so and, as of 2017, at least one of each type are under development. Both Virgin Galactic and Blue Origin are in active development, with the SpaceShipTwo spaceplane and the New Shepard capsule, respectively. Both would carry approximately a half-dozen passengers up to space for a brief time of zero gravity before returning to the same location from where the trip began. XCOR Aerospace had been developing the Lynx single-passenger spaceplane since the 2000s[29][30][31] but development was halted in 2017.[32]

National spacefaring attempts

This section lists all nations which have attempted human spaceflight programs. This should not to be confused with nations with citizens who have traveled into space including space tourists, flown or intended to fly by foreign country's or non-domestic private space systems – these are not counted as national spacefaring attempts in this list.

Nation/Organization	Space agency	Term(s) for space traveler	First launched astronaut	Date	Spacecraft	Launcher	Type
Union of Soviet Socialist Republics (1922–1991)	Soviet space program (OKB-1 Design Bureau)	космонавт (same word in:) (in Russian and Ukrainian) kosmonavt cosmonaut Ғарышкер(in Kazakh)	Yuri Gagarin	12 April 1961	Vostok spacecraft	Vostok	Orbital
United States	National Aeronautics and Space Administration (NASA)	astronaut spaceflight participant	Alan Shepard (suborbital)	5 May 1961	Mercury spacecraft	Redstone	Suborbital
United States	National Aeronautics and Space Administration (NASA)	astronaut spaceflight participant	John Glenn (orbital)	20 February 1962	Mercury spacecraft	Atlas LV-3B	Orbital
People's Republic of China	Space program of the People's Republic of China	宇航员  (Chinese) yǔhángyuán 航天员  (Chinese) hángtiānyuán	...	1973 (abandoned)	Shuguang	Long March 2A	Orbital
People's Republic of China	Space program of the People's Republic of China	宇航员  (Chinese) yǔhángyuán 航天员  (Chinese) hángtiānyuán	...	1981 (abandoned)	Piloted FSW	Long March 2	Orbital
European Space Agency	CNES / European Space Agency (ESA)	spationaute (in French) astronaut	...	1992 (abandoned)	Hermes	Ariane V	Orbital
Russia	Russian Federal Space Agency (Roscosmos)	космонавт (in Russian) kosmonavt cosmonaut	Alexander Viktorenko, Alexander Kaleri	17 March 1992	Soyuz TM-14 to MIR	Soyuz-U2	Orbital
Ba'athist Iraq (1968–2003)[note 1]	...	رجل فضاء  (Arabic) rajul faḍāʼ رائد فضاء  (Arabic) rāʼid faḍāʼ ملاح فضائي  (Arabic) mallāḥ faḍāʼiy	...	2001 (abandoned)	...	Tammouz 2 or 3	N/A
Japan	National Space Development Agency of Japan (NASDA)	宇宙飛行士  (Japanese) uchūhikōshi or アストロノート asutoronoto	...	2003 (abandoned)	HOPE	H-II	Orbital
People's Republic of China	China National Space Administration (CNSA)	宇航员  (Chinese) yǔhángyuán 航天员  (Chinese) hángtiānyuán taikonaut (太空人; tàikōng rén)	Yang Liwei	15 October 2003	Shenzhou spacecraft	Long March 2F	Orbital
Japan	Japanese Rocket Society, Kawasaki Heavy Industries and Mitsubishi Heavy Industries	宇宙飛行士  (Japanese) uchūhikōshi or アストロノート asutoronoto	...	2000s (abandoned)	Kankoh-maru	Kankoh-maru	Orbital
Japan	National Space Development Agency of Japan (JAXA)	宇宙飛行士  (Japanese) uchūhikōshi or アストロノート asutoronoto	...	2003 (abandoned)	Fuji	H-II	Orbital
India	Indian Space Research Organisation (ISRO)	Vyomanaut  (in Sanskrit)	...	2022[33]	Gaganyaan	GSLV Mk III	Orbital [34][35]
European Space Agency	European Space Agency (ESA)	astronaut	...	2020 (concept approved in 2009; but full development not begun)[36][37][38][39]	CSTS, ARV phase-2	Ariane V	Orbital
Japan	Japan Aerospace Exploration Agency (JAXA)	宇宙飛行士  (Japanese) uchūhikōshi or アストロノート asutoronoto	...	TBD	HTV-based spacecraft	H3	Orbital
Iran	Iranian Space Agency (ISA)	...	...	2019 (on hold)	ISA spacecraft	TBD	Orbital
North Korea	National Aerospace Development Administration (NADA)	...	...	2020s	NADA spacecraft	Unha 9	Orbital
Denmark	Copenhagen Suborbitals	astronaut	...	2020s	Tycho Brahe	SPICA	Suborbital
Romania	ARCAspace	astronaut	...	2020s	IAR 111	-	Suborbital

Safety concerns

There are two main sources of hazard in space flight: those due to the environment of space which make it hostile to the human body, and the potential for mechanical malfunctions of the equipment required to accomplish space flight.

Environmental hazards

See also: Bioastronautics, Space habitat, Effect of spaceflight on the human body, and Locomotion in Space

Planners of human spaceflight missions face a number of safety concerns.

Life support

The basic needs for breathable air and drinkable water are addressed by the life support system of the spacecraft.

See also: Astronautical hygiene

Medical issues

See also: Effect of spaceflight on the human body, Sleep in space, and Space medicine

Medical consequences such as possible blindness and bone loss have been associated with human space flight.[40][41]

On 31 December 2012, a NASA-supported study reported that spaceflight may harm the brain of astronauts and accelerate the onset of Alzheimer's disease.[42][43][44]

In October 2015, the NASA Office of Inspector General issued a health hazards report related to space exploration, including a human mission to Mars.[45][46]

On 2 November 2017, scientists reported that significant changes in the position and structure of the brain have been found in astronauts who have taken trips in space, based on MRI studies. Astronauts who took longer space trips were associated with greater brain changes.[47][48]

Researchers in 2018 reported, after detecting the presence on the International Space Station (ISS) of five Enterobacter bugandensis bacterial strains, none pathogenic to humans, that microorganisms on ISS should be carefully monitored to continue assuring a medically healthy environment for astronauts.[49][50]

In March 2019, NASA reported that latent viruses in humans may be activated during space missions, adding possibly more risk to astronauts in future deep-space missions.[51]

Microgravity

See also: Weightlessness

The effects of microgravity on fluid distribution around the body (greatly exaggerated).

Medical data from astronauts in low Earth orbits for long periods, dating back to the 1970s, show several adverse effects of a microgravity environment: loss of bone density, decreased muscle strength and endurance, postural instability, and reductions in aerobic capacity. Over time these deconditioning effects can impair astronauts' performance or increase their risk of injury.[52]

In a weightless environment, astronauts put almost no weight on the back muscles or leg muscles used for standing up, which causes them to weaken and get smaller. Astronauts can lose up to twenty per cent of their muscle mass on spaceflights lasting five to eleven days. The consequent loss of strength could be a serious problem in case of a landing emergency.[53] Upon return to Earth from long-duration flights, astronauts are considerably weakened, and are not allowed to drive a car for twenty-one days.[54]

Astronauts experiencing weightlessness will often lose their orientation, get motion sickness, and lose their sense of direction as their bodies try to get used to a weightless environment. When they get back to Earth, or any other mass with gravity, they have to readjust to the gravity and may have problems standing up, focusing their gaze, walking and turning. Importantly, those body motor disturbances after changing from different gravities only get worse the longer the exposure to little gravity.[55] These changes will affect operational activities including approach and landing, docking, remote manipulation, and emergencies that may happen while landing. This can be a major roadblock to mission success.

In addition, after long space flight missions, male astronauts may experience severe eyesight problems.[56][57][58][59][60] Such eyesight problems may be a major concern for future deep space flight missions, including a crewed mission to the planet Mars.[56][57][58][59][61] Long space flights can also alter a space traveler's eye movements.[62]

Radiation

See also: Health threat from cosmic rays

Comparison of Radiation Doses – includes the amount detected on the trip from Earth to Mars by the RAD on the MSL (2011–2013).[63]

Without proper shielding, the crews of missions beyond low Earth orbit (LEO) might be at risk from high-energy protons emitted by solar flares and associated solar particle events (SPEs). Lawrence Townsend of the University of Tennessee and others have studied the overall most powerful solar storm ever recorded. The flare was seen by the British astronomer Richard Carrington in September 1859. Radiation doses astronauts would receive from a Carrington-type storm could cause acute radiation sickness and possibly even death.[64] Another storm that could have incurred a lethal radiation dose if astronauts were outside the Earth's protective magnetosphere occurred during the Space Age, in fact, shortly after Apollo 16 landed and before Apollo 17 launched.[65] This solar storm of August 1972 would likely at least have caused acute illness.[66]

Another type of radiation, galactic cosmic rays, presents further challenges to human spaceflight beyond low Earth orbit.[67]

There is also some scientific concern that extended spaceflight might slow down the body's ability to protect itself against diseases.[68] Some of the problems are a weakened immune system and the activation of dormant viruses in the body. Radiation can cause both short and long term consequences to the bone marrow stem cells which create the blood and immune systems. Because the interior of a spacecraft is so small, a weakened immune system and more active viruses in the body can lead to a fast spread of infection.

Isolation

Further information: Effect of spaceflight on the human body § Psychological effects, and Psychological and sociological effects of spaceflight

During long missions, astronauts are isolated and confined into small spaces. Depression, cabin fever and other psychological problems may impact the crew's safety and mission success.[69]

Astronauts may not be able to quickly return to Earth or receive medical supplies, equipment or personnel if a medical emergency occurs. The astronauts may have to rely for long periods on their limited existing resources and medical advice from the ground.

During astronauts' stay in space, they may experience mental disorders (such as post-trauma, depression, anxiety, etc.), more than for an average person. NASA spends millions of dollars on psychological treatments for astronauts and former astronauts.[70] To date, there is no way to prevent or reduce mental problems caused by extended periods of stay in space.

Due to these mental disorders, the efficiency of their work is impaired and sometimes they are forced to send the astronauts back to Earth, which is very expensive.[71] A Russian expedition to space in 1976 was returned to Earth after the cosmonauts reported a strong odor that caused a fear of fluid leakage, but after a thorough investigation it became clear that there was no leakage or technical malfunction.  It was concluded by NASA that the cosmonauts most likely had hallucinations of the smell, which brought many unnecessary wasted expenses.

It is possible that the mental health of astronauts can be affected by the changes in the sensory systems while in prolonged space travel.

Sensory systems

During astronauts' spaceflight, they are in a very extreme state where there is no gravity. This given state and the fact that no change is taking place in the environment will result in the weakening of sensory input to the astronauts in all seven senses.

• Hearing - In the space station and spacecraft there are only mechanical noises. There can be no environmental noise; there is no medium that can transmit the sound waves. Although there are other team members who can talk to each other, their voices stop stimulating the sense of hearing, since they get used to it quickly.
• Sight - Because of the zero gravity, the body's liquids equalize in pressure throughout the body, a situation which is different from that on the Earth, where the pressures are not equal. Because of this reason, the astronauts' face swells and presses on the eyes, and therefore their vision is impaired. In addition, the landscape surrounding the astronauts is constant, which damages the visual stimulations. In addition, due to cosmic rays, astronauts may see flashes.
• Smell - The space station has a permanent odor described as the smell of gunpowder. Due to the zero gravity, the bodily fluids rise to the face and prevent the sinuses from drying up, which dulls the sense of smell.
• Taste - The sense of taste is directly affected by the sense of smell and therefore when the sense of smell is damaged, the sense of taste is also damaged. The astronauts' food is bland, and there are only certain foods that can be eaten. The food comes only once every few months when supplies arrive, and there is little to no variety.
• Touch – There are almost no physical contact changes. There is almost no human physical contact during the journey.
• The vestibular system (motion and equilibrium system) - Due to the lack of gravity, all the movement of the astronauts changes, and the vestibular system is damaged by the extreme change.
• The proprioception system (the sense of the relative position of one's own parts of the body and strength of effort being employed in movement) - As a result of the zero gravity, few forces are exerted on the astronauts' muscles and there is no input to this system.

Mechanical hazards

Space flight requires much higher velocities than ground or air transportation, which in turn requires the use of high energy density propellants for launch, and the dissipation of large amounts of energy, usually as heat, for safe reentry through the Earth's atmosphere.

Launch

See also: Launch escape system

There was no practical way for the Space Shuttle Challenger's crew to safely abort before the vehicle's violent disintegration.

Since rockets carry the potential for fire or explosive destruction, space capsules generally employ some sort of launch escape system, consisting either of a tower-mounted solid-fuel rocket to quickly carry the capsule away from the launch vehicle (employed on Mercury, Apollo, and Soyuz), or else ejection seats (employed on Vostok and Gemini) to carry astronauts out of the capsule and away for individual parachute landing. The escape tower is discarded at some point before the launch is complete, at a point where an abort can be performed using the spacecraft's engines.

Such a system is not always practical for multiple crew member vehicles (particularly spaceplanes), depending on location of egress hatch(es). When the single-hatch Vostok capsule was modified to become the 2 or 3-person Voskhod, the single-cosmonaut ejection seat could not be used, and no escape tower system was added. The two Voskhod flights in 1964 and 1965 avoided launch mishaps. The Space Shuttle carried ejection seats and escape hatches for its pilot and copilot in early flights, but these could not be used for passengers who sat below the flight deck on later flights, and so were discontinued.

There have only been two in-flight launch aborts of a crewed flight. The first occurred on Soyuz 18a on 5 April 1975. The abort occurred after the launch escape system had been jettisoned when the launch vehicle's spent second stage failed to separate before the third stage ignited. The vehicle strayed off course, and the crew separated the spacecraft and fired its engines to pull it away from the errant rocket. Both cosmonauts landed safely. The second occurred on 11 October 2018 with the launch of Soyuz MS-10. Again, both crew members survived.

In the first use of a launch escape system on a crewed flight, the planned Soyuz T-10a launch on 26 September 1983 was aborted by a launch vehicle fire 90 seconds before liftoff. Both cosmonauts aboard landed safely.

The only crew fatality during launch occurred on 28 January 1986, when the Space Shuttle Challenger broke apart 73 seconds after liftoff, due to failure of a solid rocket booster seal which caused separation of the booster and failure of the external fuel tank, resulting in explosion of the fuel. All seven crew members were killed.

Extravehicular activity

Despite the ever-present risks related to mechanical failures while working in open space, no spacewalking astronaut has ever been lost. There is a requirement for spacewalking astronauts to use tethers and sometimes supplementary anchors. If those fail, a spacewalking astronaut would most probably float away according to relevant forces that were acting on him when breaking loose. Astronaut would possibly be spinning as kicking and flailing is of no use. At the right angle and velocity, he might even re-enter the Earth's atmosphere and burn away completely. NASA has protocols for such situations: astronauts would be wearing an emergency jetpack, which would automatically counter any tumbling to stabilize them. Then NASA's plan states that astronauts should take manual control and fly back to safety.

However, if the pack's 3 pounds (1.4 kg) of fuel runs out, and if there is no other astronaut in close proximity to help, or if the air lock is irreparably damaged, the outcome would certainly be fatal. At the moment, there is no spacecraft to save an astronaut floating in space as the only one with a rescue-ready air-locked compartment — the Space Shuttle — retired 9 years ago. There's approximately a litre of water available via straw in astronaut's helmet. They would wait roughly for 7.5 hours for breathable air to run out before dying of suffocation.[72]

Reentry and landing

The single pilot of Soyuz 1, Vladimir Komarov was killed when his capsule's parachutes failed during an emergency landing on 24 April 1967, causing the capsule to crash.

The crew of seven aboard the Space Shuttle Columbia were killed on reentry after completing a successful mission in space on 1 February 2003. A wing leading edge reinforced carbon-carbon heat shield had been damaged by a piece of frozen external tank foam insulation which broke off and struck the wing during launch. Hot reentry gasses entered and destroyed the wing structure, leading to the breakup of the orbiter vehicle.

Artificial atmosphere

There are two basic choices for an artificial atmosphere: either an Earth-like mixture of oxygen in an inert gas such as nitrogen or helium, or pure oxygen, which can be used at lower than standard atmospheric pressure. A nitrogen-oxygen mixture is used in the International Space Station and Soyuz spacecraft, while low-pressure pure oxygen is commonly used in space suits for extravehicular activity.

The use of a gas mixture carries the risk of decompression sickness (commonly known as "the bends") when transitioning to or from the pure oxygen space suit environment. There have also been instances of injury and fatalities caused by suffocation in the presence of too much nitrogen and not enough oxygen.

• In 1960, McDonnell Aircraft test pilot G.B. North passed out and was seriously injured when testing a Mercury cabin/spacesuit atmosphere system in a vacuum chamber, due to nitrogen-rich air leaking from the cabin into his spacesuit feed.[73] This incident led NASA to decide on a pure oxygen atmosphere for the Mercury, Gemini, and Apollo spacecraft.
• In 1981, three pad workers were killed by a nitrogen-rich atmosphere in the aft engine compartment of the Space Shuttle Columbia at the Kennedy Space Center Launch Complex 39.[74]
• In 1995, two pad workers were similarly killed by a nitrogen leak in a confined area of the Ariane 5 launch pad at Guiana Space Centre.[75]

A pure oxygen atmosphere carries the risk of fire. The original design of the Apollo spacecraft used pure oxygen at greater than atmospheric pressure prior to launch. An electrical fire started in the cabin of Apollo 1 during a ground test at Cape Kennedy Air Force Station Launch Complex 34 on 27 January 1967, and spread rapidly. The high pressure (increased even higher by the fire) prevented removal of the plug door hatch cover in time to rescue the crew. All three, Gus Grissom, Ed White, and Roger Chaffee, were killed.[76] This led NASA to use a nitrogen/oxygen atmosphere before launch, and low pressure pure oxygen only in space.

Reliability

See also: Reliability engineering

The March 1966 Gemini 8 mission was aborted in orbit when an attitude control system thruster stuck in the on position, sending the craft into a dangerous spin which threatened the lives of Neil Armstrong and David Scott. Armstrong had to shut the control system off and use the reentry control system to stop the spin. The craft made an emergency reentry and the astronauts landed safely. The most probable cause was determined to be an electrical short due to a static electricity discharge, which caused the thruster to remain powered even when switched off. The control system was modified to put each thruster on its own isolated circuit.

The third lunar landing expedition Apollo 13 in April 1970, was aborted and the lives of the crew, James Lovell, Jack Swigert and Fred Haise, were threatened by failure of a cryogenic liquid oxygen tank en route to the Moon. The tank burst when electrical power was applied to internal stirring fans in the tank, causing the immediate loss of all of its contents, and also damaging the second tank, causing the loss of its remaining oxygen in a span of 130 minutes. This in turn caused loss of electrical power provided by fuel cells to the command spacecraft. The crew managed to return to Earth safely by using the lunar landing craft as a "life boat". The tank failure was determined to be caused by two mistakes. The tank's drain fitting had been damaged when it was dropped during factory testing. This necessitated use of its internal heaters to boil out the oxygen after a pre-launch test, which in turn damaged the fan wiring's electrical insulation because the thermostats on the heaters did not meet the required voltage rating due to a vendor miscommunication.

The crew of Soyuz 11 were killed on 30 June 1971 by a combination of mechanical malfunctions: they were asphyxiated due to cabin decompression following separation of their descent capsule from the service module. A cabin ventilation valve had been jolted open at an altitude of 168 kilometres (551,000 ft) by the stronger than expected shock of explosive separation bolts which were designed to fire sequentially, but in fact, had fired simultaneously. The loss of pressure became fatal within about 30 seconds.[77]

Fatality risk

Further information: List of spaceflight-related accidents and incidents § Non-astronaut fatalities

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

Date	Mission	Accident cause	Deaths	Cause of death
27 January 1967	Apollo 1	Electrical fire in cabin, spread quickly by 16.7 psi (1.15 bar) pure oxygen atmosphere and flammable nylon materials in cabin and space suits, during pre-launch test; inability to remove plug door hatch cover due to internal pressure; rupture of cabin wall allowed outside air to enter, causing heavy smoke and soot	3	Cardiac arrest from carbon monoxide poisoning
15 November 1967	X-15 Flight 3-65-97	The accident board found that the cockpit instrumentation had been functioning properly, and concluded that Adams had lost control of the X-15 as a result of a combination of distraction, misinterpretation of his instrumentation display, and possible vertigo. The electrical disturbance early in the flight degraded the overall effectiveness of the aircraft's control system and further added to pilot workload.	1	Vehicle breakup
24 April 1967	Soyuz 1	Malfunction of primary landing parachute, and entanglement of reserve parachute; loss of 50% electrical power and spacecraft control problems necessitated emergency abort	1	Trauma from crash landing
30 June 1971	Soyuz 11	Loss of cabin pressurization due to valve opening upon Orbital Module separation before re-entry	3	Asphyxia
28 January 1986	STS-51L Space Shuttle Challenger	Failure of o-ring inter-segment seal in one Solid Rocket Booster in extreme cold launch temperature, allowing hot gases to penetrate casing and burn through a strut connecting booster to the External Tank; tank failure; rapid combustion of fuel; orbiter breakup from abnormal aerodynamic forces	7	Asphyxia from cabin breach, or trauma from water impact[78]
1 February 2003	STS-107 Space Shuttle Columbia	Damaged reinforced carbon-carbon heat shield panel on wing's leading edge, caused by piece of External Tank foam insulation broken off during launch; penetration of hot atmospheric gases during re-entry, leading to structural failure of wing, loss of control and disintegration of orbiter	7	Asphyxia from cabin breach, trauma from dynamic load environment as orbiter broke up[79]
31 October 2014	SpaceShipTwo VSS Enterprise powered drop-test	Copilot error: premature deployment of "feathering" descent air-braking system caused disintegration of vehicle in flight; pilot survived, copilot died	1	Trauma from crash

Human representation and participation

See also: Space law, Space colonization, and Human outpost

Women

Main article: Women in space

The first woman to ever enter space was Valentina Tereshkova. She flew in 1963 but it was not until the 1980s that another woman entered space again. All astronauts were required to be military test pilots at the time and women were not able to enter this career, this is one reason for the delay in allowing women to join space crews. After the rule changed, Svetlana Savitskaya became the second woman to enter space, she was also from the Soviet Union. Sally Ride became the next woman to enter space and the first woman to enter space through the United States program.

Since then, eleven other countries have allowed women astronauts. Due to some slow changes in the space programs to allow women. The first all female space walk occurred in 2018, including Christina Koch and Jessica Meir. These two women have both participated in separate space walks with NASA. The first woman to go to the moon is planned for 2024.

Despite these developments women are still underrepresented among astronauts and especially cosmonauts. Issues that block potential applicants from the programs and limit the space missions they are able to go on, are for example:

• agencies limiting women to half as much time in space than men, argueing with unresearched potential risks for cancer.[80]
• a lack of space suits sized appropriately for female astronauts.[81]

Additionally women have been treated in discriminatory ways, for example as with Sally Ride by being scrutinized more than her male counterparts and asked sexist questions by the press.

See also

• List of human spaceflight programs
• List of human spaceflights
• List of spaceflight records
• List of crewed spacecraft
• Animals in space
• Monkeys and apes in space
• Crewed Mars rover
• Mars to Stay
• NewSpace
• Space medicine
• Tourism on the Moon
• Women in space

Notes

1. According to a press-release of Iraqi News Agency of 5 December 1989 about the first (and last) test of the Tammouz space launcher, Iraq intended to develop crewed space facilities by the end of the century. These plans were put to an end by the Gulf War of 1991 and the economic hard times that followed.

References

1. "Counting the Many Ways the International Space Station Benefits Humanity". Retrieved 4 May 2019.
2. "Crew Dragon Docks to Space Station". Retrieved 6 June 2020.
3. "FY 2011 Budget". NASA. Archived from the original on 21 December 2010.
4. "NASA Hails Success of Commercial Space Program". nasa.gov. Retrieved 24 July 2014.
5. "SpaceX Astronauts Reach Space Station After Milestone Voyage". www.bloomberg.com. Retrieved 16 June 2020.
6. Kennedy, John F. (25 May 1961). Special Message to Congress on Urgent National Needs (Motion picture (excerpt)). Boston, MA: John F. Kennedy Presidential Library and Museum. Accession Number: TNC:200; Digital Identifier: TNC-200-2. Retrieved 1 August 2013.
7. Loff, Sarah (21 October 2013). "Gemini: Stepping Stone to the Moon". Gemini: Bridge to the Moon. Washington, DC: National Aeronautics and Space Administration. Archived from the original on 21 December 2014. Retrieved 4 January 2015.CS1 maint: ref=harv (link)
8. Siddiqi, Asif. Challenge To Apollo The Soviet Union and The Space Race, 1945–1974. NASA. p. 832.
9. David Michael Harland (2004). The Story of the Space Shuttle. Springer Praxis. p. 444. ISBN 978-1-85233-793-3.
10. 九章与中国卫星. Chinese Academy of Sciences. 16 October 2007. Archived from the original on 14 March 2008. Retrieved 3 July 2008.
11. 首批航天员19人胜出 为后来积累了宝贵的经验. 雷霆万钧. 16 September 2005. Archived from the original on 22 December 2005. Retrieved 24 July 2008.
12. Congressional watchdog finds NASA's new rocket is in trouble Archived 29 November 2011 at the Wayback Machine. Orlando Sentinel blog summary of official reports. 3 November 2008
13. Klamper, Amy (8 September 2009) White House Panel Spells Out Human Spaceflight Options for NASA. Space News
14. https://www.space.com/42725-virgin-galactic-spaceshiptwo-unity-4th-powered-flight-twitter-updates.html
15. David, Leonard. (11 January 2014) Will Commercial Space Travel Blast Off in 2014?. Space.com. Retrieved on 22 November 2016.
16. Bolden, Charlie. "American Companies Selected to Return Astronaut Launches to American Soil". NASA.gov. Retrieved 16 September 2014.
17. Foust, Jeff (19 September 2014). "NASA Commercial Crew Awards Leave Unanswered Questions". Space News. Retrieved 21 September 2014. "We basically awarded based on the proposals that we were given", Kathy Lueders, NASA commercial crew program manager, said in a teleconference with reporters after the announcement. "Both contracts have the same requirements. The companies proposed the value within which they were able to do the work, and the government accepted that".
18. "RELEASE 14-256 NASA Chooses American Companies to Transport U.S. Astronauts to International Space Station". www.nasa.gov. NASA. Retrieved 29 October 2014.
19. Garcia, Mark (18 October 2019). "NASA Astronauts Wrap Up Historic All-Woman Spacewalk". NASA. Retrieved 23 January 2020.
20. Potter, Sean (30 May 2020). "NASA Astronauts Launch from America in Test of SpaceX Crew Dragon". NASA. Retrieved 31 May 2020.
21. "Style Guide". NASA. Retrieved 6 January 2016.
22. "Scientists Discuss Indian Manned Space Mission". Indian Space Research Organisation. 7 November 2006.
23. Rao, Mukund Kadursrinivas; Murthi, Sridhara, K. R.; Prasad M. Y. S. "THE DECISION FOR INDIAN HUMAN SPACEFLIGHT PROGRAMME - POLITICAL PERSPECTIVES, NATIONAL RELEVANCE AND TECHNOLOGICAL CHALLENGES" (PDF). International Astronautical Federation.
24. "Independence Day 2018 Live Updates: 'We will put an Indian on space before 2022,' says Narendra Modi at Red Fort". Firstpost.com. Retrieved 21 June 2020.
25. "ISRO Stalls Launch of Uncrewed Gaganyaan Mission and Chandrayaan-3 Due to COVID-19". The Weather Channel. 11 June 2020. Retrieved 13 June 2020.
26. Strauss, Neil (15 November 2017). "Elon Musk: The Architect of Tomorrow". Rolling Stone. Retrieved 15 November 2017.
27. Starship Earth to Earth, SpaceX, 28 September 2017, accessed 23 December 2017.
28. Foust, Jeff (15 October 2017). "Musk offers more technical details on BFR system". SpaceNews. Retrieved 15 October 2017. [the] spaceship portion of the BFR, which would transport people on point-to-point suborbital flights or on missions to the moon or Mars, will be tested on Earth first in a series of short hops. ... a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance ... fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines.
29. (2012) SXC - Buying your tickets into space! Archived 6 March 2013 at the Wayback Machine SXC web page, Retrieved 5 April 2013
30. Staff writers (6 October 2010). "Space Expedition Corporation Announces Wet Lease of XCOR Lynx Suborbital". Space Media Network Promotions. Space-Travel.com. Retrieved 6 October 2010.
31. "Space Experience Curacao". Home. Space Experience Curacao. 2009–2010. Retrieved 6 October 2010.
32. http://spacenews.com/xcor-aerospace-files-for-bankruptcy/
33. Gaganyaan mission to take Indian astronaut to space by 2022: PM Modi. The Hindu. 15 August 2018.
34. ETtech.com. "Four years is tight, but can achieve the human spaceflight: ISRO's K Sivan - ETtech". ETtech.com. Retrieved 15 August 2018.
35. IANS (15 August 2018). "India will put man in space for seven days: ISRO Chairman". Business Standard India. Retrieved 15 August 2018.
36. Amos, Jonathan (7 July 2009). "Europe targets manned spaceship". BBC News. Retrieved 27 March 2010.
37. Apollo-like capsule chosen for Crew Space Transportation System, 22 May 2008
38. "Jules Verne" Automated Transfer Vehicle (ATV) Re-entry. Information Kit (PDF). Updated September 2008. European Space Agency. Retrieved on 7 August 2011.
39. Amos, Jonathan (26 November 2008). "Europe's 10bn-euro space vision". BBC News. Retrieved 27 March 2010.
40. Chang, Kenneth (27 January 2014). "Beings Not Made for Space". The New York Times. Retrieved 27 January 2014.
41. Mann, Adam (23 July 2012). "Blindness, Bone Loss, and Space Farts: Astronaut Medical Oddities". Wired. Retrieved 23 July 2012.
42. Cherry, Jonathan D.; Frost, Jeffrey L.; Lemere, Cynthia A.; Williams, Jacqueline P.; Olschowka, John A.; O'Banion, M. Kerry (2012). "Galactic Cosmic Radiation Leads to Cognitive Impairment and Increased Aβ Plaque Accumulation in a Mouse Model of Alzheimer's Disease". PLoS ONE. 7 (12): e53275. Bibcode:2012PLoSO...753275C. doi:10.1371/journal.pone.0053275. PMC 3534034. PMID 23300905.
43. "Study Shows that Space Travel is Harmful to the Brain and Could Accelerate Onset of Alzheimer's". SpaceRef. 1 January 2013. Retrieved 7 January 2013.
44. Cowing, Keith (3 January 2013). "Important Research Results NASA Is Not Talking About (Update)". NASA Watch. Retrieved 7 January 2013.
45. Dunn, Marcia (29 October 2015). "Report: NASA needs better handle on health hazards for Mars". Associated Press. Retrieved 30 October 2015.
46. Staff (29 October 2015). "NASA's Efforts to Manage Health and Human Performance Risks for Space Exploration (IG-16-003)" (PDF). NASA. Retrieved 29 October 2015.
47. Roberts, Donna R.; et al. (2 November 2017). "Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI". New England Journal of Medicine. 377 (18): 1746–1753. doi:10.1056/NEJMoa1705129. PMID 29091569.
48. Foley, Katherine Ellen (3 November 2017). "Astronauts who take long trips to space return with brains that have floated to the top of their skulls". Quartz. Retrieved 3 November 2017.
49. BioMed Central (22 November 2018). "ISS microbes should be monitored to avoid threat to astronaut health". EurekAlert!. Retrieved 25 November 2018.
50. Singh, Nitin K.; et al. (23 November 2018). "Multi-drug resistant Enterobacter bugandensis species isolated from the International Space Station and comparative genomic analyses with human pathogenic strains". BMC Microbiology. 18 (1): 175. doi:10.1186/s12866-018-1325-2. PMC 6251167. PMID 30466389.
51. Staff (15 March 2019). "Dormant viruses activate during spaceflight -- NASA investigates - The stress of spaceflight gives viruses a holiday from immune surveillance, putting future deep-space missions in jeopardy". EurekAlert!. Retrieved 16 March 2019.
52. "Exploration Systems Human Research Program – Exercise Countermeasures". NASA. Archived from the original on 11 October 2008.
53. "NASA Information: Muscle Atrophy" (PDF). NASA. Retrieved 20 November 2015.
54. "Earth Living Is Tough for Astronaut Used to Space". Space.com. Retrieved 21 November 2015.
55. Watson, Traci (11 November 2007). "Readjusting to gravity anti-fun for astronauts". ABC News. Retrieved 14 February 2020.
56. Mader, T. H.; et al. (2011). "Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts after Long-duration Space Flight". Ophthalmology. 118 (10): 2058–2069. doi:10.1016/j.ophtha.2011.06.021. PMID 21849212.
57. Puiu, Tibi (9 November 2011). "Astronauts' vision severely affected during long space missions". zmescience.com. Retrieved 9 February 2012.
58. News (CNN-TV, 02/09/2012) – Video (02:14) – Male Astronauts Return With Eye Problems. Cnn.com (9 February 2012). Retrieved on 22 November 2016.
59. "Spaceflight Bad for Astronauts' Vision, Study Suggests". Space.com. 13 March 2012. Retrieved 14 March 2012.
60. Kramer, Larry A.; et al. (13 March 2012). "Orbital and Intracranial Effects of Microgravity: Findings at 3-T MR Imaging". Radiology. 263 (3): 819–27. doi:10.1148/radiol.12111986. PMID 22416248.
61. Fong, MD, Kevin (12 February 2014). "The Strange, Deadly Effects Mars Would Have on Your Body". Wired. Retrieved 12 February 2014.
62. Alexander, Robert; Macknik, Stephen; Martinez-Conde, Susana (2020). "Microsaccades in applied environments: Real-world applications of fixational eye movement measurements". Journal of Eye Movement Research. 12 (6). doi:10.16910/jemr.12.6.15.
63. Kerr, Richard (31 May 2013). "Radiation Will Make Astronauts' Trip to Mars Even Riskier". Science. 340 (6136): 1031. Bibcode:2013Sci...340.1031K. doi:10.1126/science.340.6136.1031. PMID 23723213.
64. Battersby, Stephen (21 March 2005). "Superflares could kill unprotected astronauts". New Scientist.
65. Lockwood, Mike; M. Hapgood (2007). "The Rough Guide to the Moon and Mars". Astron. Geophys. 48 (6): 11–17. doi:10.1111/j.1468-4004.2007.48611.x.
66. Parsons, Jennifer L.; L. W. Townsend (2000). "Interplanetary Crew Dose Rates for the August 1972 Solar Particle Event". Radiat. Res. 153 (6): 729–733. doi:10.1667/0033-7587(2000)153[0729:ICDRFT]2.0.CO;2.
67. Space Radiation Hazards and the Vision for Space Exploration. NAP. 2006. ISBN 978-0-309-10264-3.
68. Gueguinou, N.; Huin-Schohn, C.; Bascove, M.; Bueb, J.-L.; Tschirhart, E.; Legrand-Frossi, C.; Frippiat, J.-P. (2009). "Could spaceflight-associated immune system weakening preclude the expansion of human presence beyond Earth's orbit". Journal of Leukocyte Biology. 86 (5): 1027–1038. doi:10.1189/jlb.0309167. PMID 19690292.
69. Flynn, Christopher F. (1 June 2005). "An Operational Approach to Long-Duration Mission Behavioral Health and Performance Factors". Aviation, Space, and Environmental Medicine. 76 (6): B42–B51.
70. Kanas, Nick; Manzey, Dietrich (2008). Space psychology and psychiatry (2nd ed.). Dordrecht: Springer. ISBN 9781402067709. OCLC 233972618.
71. Bell, Vaughan (5 October 2014). "Isolation and hallucinations: the mental health challenges faced by astronauts". The Observer. ISSN 0029-7712. Retrieved 1 February 2019.
72. Sofge, Eric. "What Happens If An Astronaut Floats Off In Space?". Popular Science.
73. Giblin, Kelly A. (Spring 1998). "Fire in the Cockpit!". American Heritage of Invention & Technology. American Heritage Publishing. 13 (4). Archived from the original on 20 November 2008. Retrieved 23 March 2011.
74. 1981 KSC Chronology Part 1 – pages 84, 85, 100; Part 2 – pages 181, 194, 195, NASA
75. "Fatal accident at the Guiana Space Centre", ESA Portal, 5 May 1993
76. Orloff, Richard W. (September 2004) [First published 2000]. "Apollo 1 – The Fire: 27 January 1967". Apollo by the Numbers: A Statistical Reference. NASA History Division, Office of Policy and Plans. NASA History Series. Washington, D.C.: NASA. ISBN 978-0-16-050631-4. LCCN 00061677. NASA SP-2000-4029. Retrieved 12 July 2013.
77. NASA (1974). "The Partnership: A History of the Apollo-Soyuz Test Project". NASA. Archived from the original on 23 August 2007. Retrieved 20 October 2007.
78. "Report from Joseph P. Kerwin, biomedical specialist from the Johnson Space Center in Houston, Texas, relating to the deaths of the astronauts in the Challenger accident". NASA. Archived from the original on 3 January 2013.
79. "COLUMBIA CREW SURVIVAL INVESTIGATION REPORT" (PDF). NASA.gov. NASA.
80. Kramer, Miriam (27 August 2013). "Female Astronauts Face Discrimination from Space Radiation Concerns, Astronauts Say". Space.com. Purch. Retrieved 7 January 2017.
81. Sokolowski, Susan L. (5 April 2019). "Female astronauts: How performance products like space suits and bras are designed to pave the way for women's accomplishments". The Conversation. Retrieved 10 May 2020.

Bibliography

• David Darling: The complete book of spaceflight. From Apollo 1 to Zero gravity. Wiley, Hoboken NJ 2003, ISBN 0-471-05649-9.
• Wiley J. Larson (Hrsg.): Human spaceflight – mission analysis and design. McGraw-Hill, New York NY 2003, ISBN 0-07-236811-X.
• Donald Rapp: Human missions to Mars – enabling technologies for exploring the red planet. Springer u. a., Berlin u. a. 2008, ISBN 978-3-540-72938-9.
• Haeuplik-Meusburger: Architecture for Astronauts – An Activity based Approach. Springer Praxis Books, 2011, ISBN 978-3-7091-0666-2.

External links

• NASA Human Space Flight (United States of America)
• Human Spaceflight Profile by NASA's Solar System Exploration
• Transitioning to the NASA Constellation Program
• U.S. Spaceflight History