Human spaceflight is
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.
The
Soviet
Union
/Russia
, United States
and China
are the only
three countries to have independent human spaceflight
capability. As of 2009, 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
First human spaceflights
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.
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.
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 to have launched 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 and
Buzz Aldrin became the first people to set foot
on the Moon. Six missions landed in total, numbered Apollo
11–
17, excluding
Apollo 13. Altogether twelve men walked on the
Moon, 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. , citizens from 33 nations
(including
space tourists) have flown
in space aboard Soviet, American, Russian, and Chinese
spacecraft.
Space programs
As of
2009, human spaceflight missions have been conducted by the former
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.
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
- Successfully executed manned programs are in
bold.
- Suborbital spaceflights
are in italics.
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
Without proper shielding the crews of missions beyond low Earth
orbit (LEO) might be at risk from high-energy protons emitted by
solar flares.
Lawrence Townsend of the University of
Tennessee and others have studied the most powerful solar flare
ever recorded. That flare was seen by the British astronomer
Richard Carrington in September
1859. Radiation doses astronauts would receive from a
Carrington-type flare could cause acute radiation sickness and
possibly even death.
Another type of radiation,
galactic
cosmic rays, present further challenges to human spaceflight
beyond LEO.
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 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
During long missions, astronauts are
isolated and confined into small
spaces.
Depression,
cabin fever and other psychological problems may
result that impact crew safety and mission success.
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.
Launch safety
Reentry safety
Reliability
Fatality risk
, 18 crew members have died during actual spaceflight missions (see table). Over 100 others have died in accidents during activity directly related to spaceflight missions or testing.
References
- Peter Bond, Obituary: Lt-Gen Kerim Kerimov,
The
Independent, 7 April 2003.
- According to a press-release of Iraqi News Agency of December
5, 1989 about the first (and last) test of the Tammouz space launcher,
Iraq intended to develop
manned 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.
- http://news.bbc.co.uk/2/hi/science/nature/8139347.stm
-
http://www.flightglobal.com/articles/2008/05/22/223941/apollo-like-capsule-chosen-for-crew-space-transportation.html
-
http://esamultimedia.esa.int/docs/ATV/infokit/english/Complete_Infokit_ATVreentry.pdf
- http://news.bbc.co.uk/1/hi/sci/tech/7749761.stm
- in 2006 Malaysia proposed the joint space program of islamic
world with development of independent manned space facilities
See also
- Lists
External links