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Human spaceflight

By Wikipedia,
the free encyclopedia,

http://en.wikipedia.org/wiki/Human_spaceflight


Edward White on a spacewalk during the Gemini 4 mission.
Edward White on a spacewalk during the Gemini 4 mission.

A human spaceflight is a spaceflight with a human crew, and possibly passengers. This makes it unlike robotic space probes or remotely-controlled satellites. Human spaceflight is sometimes called manned spaceflight, a term now deprecated by major space agencies in favor of its gender-neutral alternative.

As of 2008 human spaceflights are being actively launched by the Soyuz programme conducted by the Russian Federal Space Agency, the Space Shuttle program conducted by NASA and the Shenzhou program conducted by the China National Space Administration.

A number of non-governmental startup companies have sprung up in recent years, hoping to create a space tourism industry. For a list of such companies, and the spacecraft they are currently building, see list of space tourism companies.

History

Prehistory


Arabic manuscript of the One Thousand and One Nights
Arabic manuscript of the One Thousand and One Nights

The ancient Indian epics, Mahabharata and Ramayana, feature mythical Vimana flying machines that were able to fly within the Earth's atmosphere, and able to travel into space and travel submerged under water. At around 125 AD, a Syrian satirist named Lucian wrote a book on space flight called True Histories. The book was full of tall, unbelievable tales and travelogues on visits to the sun and the moon. Today, the book could easily be discarded as the fantasy of a people of a bygone era. But it was significant in the sense that it kindled the curiosities of the people of the day and stimulated interest in outer space and space travel.


Kaguya-hime returning to the Moon in The Tale of the Bamboo Cutter
Kaguya-hime returning to the Moon in The Tale of the Bamboo Cutter

During the Middle Ages, several stories within the One Thousand and One Nights (Arabian Nights) feature fantastic tales of human spaceflight. For example, "The Adventures of Bulukiya" features the protagonist Bulukiya journeying to the Garden of Eden and to Jahannam, and travelling across the cosmos to different worlds much larger than his own world, anticipating elements of galactic science fiction. "The Ebony Horse" features a robot in the form of a flying mechanical horse controlled using keys that could fly into outer space and towards the Sun. "The Ebony Horse" can be considered an early example of proto-science fiction.


Illustration courtesy of Civil Air Patrol depicting the legend of Wan Hu, wearing a Song Dynasty official suit
Illustration courtesy of Civil Air Patrol depicting the legend of Wan Hu, wearing a Song Dynasty official suit

The 10th century Japanese narrative, The Tale of the Bamboo Cutter, may also be considered proto-science fiction. The protagonist of the story, Kaguya-hime, is a princess from the Moon who is sent to Earth for safety during a celestial war, and is found and raised by a bamboo cutter in Japan. She is later taken back to the Moon by her real extraterrestrial family. A manuscript illustration depicts a round flying machine similar to a flying saucer.

American author Herbert S. Zim claimed in 1945 that there is a Chinese legend where a scientist named Wan Hu (d. 1500) in the early Ming Dynasty attempted to travel through space with the help of rockets. However, the account is unsourced, and no known Chinese account exists. In the story, Wan tied 47 rockets filled with explosives to the chair in which he was sitting and ignited them. There was a large explosion, but when the smoke cleared Wan Hu was gone and never seen again.

First human spaceflights


Yuri Gagarin, the first man in space, in his space suit during the Vostok 1 mission
Yuri Gagarin, the first man in space, in his space suit during the Vostok 1 mission

The first human spaceflight was undertaken on April 12, 1961, when cosmonaut Yuri Gagarin made one orbit around the Earth aboard the Vostok 1 spacecraft, launched by the Soviet space program and designed by the rocket scientists Sergey Korolyov and Kerim Kerimov. Valentina Tereshkova became the first woman in space on board Vostok 6 on June 16, 1963. Both spacecraft were launched by Vostok 3KA launch vehicles. Alexei Leonov made the first spacewalk when he left the Voskhod 2 on March 8, 1965. Svetlana Savitskaya became the first woman to do so on July 25, 1984.


Sergey Korolyov, one of the lead architects behind the Vostok 1 mission
Sergey Korolyov, one of the lead architects behind the Vostok 1 mission

The United States became the second nation (and for four decades, one of only two) to achieve manned spaceflight, with the suborbital flight of astronaut Alan Shepard aboard Freedom 7, carried out as part of Project Mercury. The spacecraft was launched on May 5, 1961 on a Redstone rocket. The first U.S. orbital flight was that of John Glenn aboard Friendship 7, which was launched February 20, 1962 on an Atlas rocket. Since April 12, 1981 the U.S. has conducted all its human spaceflight missions with reusable Space Shuttles. 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 July 1999 she became the first woman to command a U.S. spacecraft.


Kerim Kerimov, one of the lead architects behind the Vostok 1 mission
Kerim Kerimov, one of the lead architects behind the Vostok 1 mission

The People's Republic of China became the third nation to achieve human spaceflight when Yang Liwei launched into space on a Chinese-made vehicle, the Shenzhou 5, on October 15, 2003. The flight made China the third nation capable of launching its own manned spacecraft using its own launcher. Previous European (Hermes) and Japanese (HOPE-X) domestic manned programs were abandoned after years of development, as was the first Chinese attempt, the Shuguang spacecraft.

The furthest destination for a human spaceflight mission has been the Moon, and as of 2008 the only missions to the Moon have been those conducted by NASA as part of the Apollo program. The first such mission, Apollo 8, orbited the Moon but did not land. The first Moon landing mission was Apollo 11, during which—on July 20, 1969 -- Neil Armstrong became the first person to set foot on the Moon. Six missions landed in total, numbered Apollo 11–17, excluding Apollo 13. Altogether twelve men reached the Moon's surface, the only humans to have been on an extraterrestrial body. The Soviet Union discontinued its program for lunar orbiting and landing of human spaceflight missions on June 24, 1974 when Valentin Glushko became General Designer of NPO Energiya.

The longest single human spaceflight is that of Valeriy Polyakov, who left earth on January 8, 1994, and didn't return until March 22, 1995 (a total of 437 days 17 hr. 58 min. 16 sec. aboard). Sergei Krikalyov has spent the most time of anyone in space, 803 days, 9 hours, and 39 seconds altogether. The longest period of continuous human presence in space lasted as long as 3,644 days, eight days short of 10 years, spanning the launch of Soyuz TM-8 on September 5, 1989 to the landing of Soyuz TM-29 on August 28, 1999.

For many years beginning in 1961, only two countries, the USSR (later Russia) and United States, had their own astronauts. Later, cosmonauts and astronauts from other nations flew in space, beginning with the flight of Vladimir Remek, a Czech, on a Soviet spacecraft on March 2, 1978. As of 2007, citizens from 33 nations (including space tourists) have flown in space aboard Soviet, American, Russian, and Chinese spacecraft.

Space programs

As of 2007, human spaceflight missions have been conducted by the Soviet Union (/Russia), the United States, the People's Republic of China and by the private spaceflight company Scaled Composites.

Several other countries and space agencies have announced and begun human spaceflight programs by their own technology, including India (ISRO), Ecuador (EXA), Japan (JAXA), Iran (ISA), Malaysia (MNSA) and Turkey.


Countries which have human spaceflight agendas.
Countries which have human spaceflight agendas.

Currently the following spacecraft and spaceports are used for launching human spaceflights:

Historically, the following spacecraft and spaceports have also been used for human spaceflight launches:

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 June 21, 2004, when SpaceShipOne conducted a suborbital flight. SpaceShipOne captured the prize on October 4, 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 now use the term "human spaceflight" to refer to their programs of launching people into space. Traditionally, these endeavors have been referred to as "manned space missions".

National spacefaring attempts

Successful manned programs are in bold.


Safety concerns

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

Life support

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

Medical issues

Effects of microgravity

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.

In a weightless environment, astronauts put almost no weight on the back muscles or leg muscles used for standing up. Those muscles then start to weaken and eventually get smaller. If there is an emergency at landing, the loss of muscles, and consequently the loss of strength can be a serious problem. Sometimes, astronauts can lose up to 25% of their muscle mass on long term flights. When they get back to ground, they will be considerably weakened and will be out of action for a while.

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. These changes will affect operational activities including approach and landing, docking, remote manipulation, and emergencies that happen by landing. This is a big problem for mission success.

Radiation damage to the immune system

Another factor is that extended space flight might slow down the body’s ability to protect itself against diseases. 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 blood 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

During long missions, astronauts have to go through the isolation and confinement of a space environment. People isolated for a long period of time can go into depression. This can negatively influence the mission’s success. Not only are astronauts subjected to near total isolation from the rest of the world, but they have very limited space to move around. These factors can lead to cabin fever and several other psychological problems.

When on long missions, astronauts will not be able to quickly return to Earth if a medical emergency occurs. For example, a scientist working in the south pole found a lump in her breast and had to wait two months before a helicopter could come in. In space, even that is not an option. When a medical emergency happens, the astronauts have to rely on the crew and the computers to solve the problem.

Launch safety

Reentry safety

Reliability

Future of US program

On May 7, 2009 the Obama Administration announced the launch of an independent review of planned U.S. human space flight activities with the goal of ensuring that the nation is on a vigorous and sustainable path to achieving its boldest aspirations in space. The review committee will be conducted by a blue-ribbon panel of experts led by Norman Augustine, the former CEO of Lockheed Martin, who served on the President’s Council of Advisors on Science and Technology under Democratic and Republican presidents.

The "Review of United States Human Space Flight Plans Committee" is to examine ongoing and planned National Aeronautics and Space Administration (NASA) development activities, as well as potential alternatives, and present options for advancing a safe, innovative, affordable, and sustainable human space flight program in the years following Space Shuttle retirement. The panel will work closely with NASA and will seek input from the United States Congress, the White House, the public, industry, and international partners as it develops its options. It is to present its results in time to support an Administration decision on the way forward by August 2009.

Read the full press release: OSTP Press Release Announcing Review (pdf, 50k)

See also

Lists

External links




Text from Wikipedia is available under the Creative Commons Attribution/Share-Alike License; additional terms may apply.


Published - July 2009














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