Space exploration

Space exploration is the physical exploration of outer space objects and generally anything that involves the technologies, science, and politics regarding space endeavors.

It was given a boost by the launch of Sputnik 1, the first man-made object to orbit the Earth, which set off the space race between the United States and the Soviet Union. Two other famous achievements in the early days were putting the first man in space, Yuri Gagarin aboard Vostok 1, and the first people on the Moon, Neil Armstrong and Buzz Aldrin aboard Apollo 11 with Michael Collins. After 30 years of competition focus has started shifting from competition to cooperation and from one-off flights to renewable hardware and most recently to the building of extra-terrestrial launch platforms, such as from a space station and possibly from the Moon.

Orbiting and reaching space

From a spaceflight perspective, the definition of space usually used is that space begins 100 km (62 miles) above Earth's surface. The United States sometimes uses a 50 mile definition. (See boundary to space.)

Achieving orbit is essential for going anywhere else, such as to the Moon or Mars. The first successful orbital launch was of the Soviet unmanned Sputnik I mission on October 4, 1957. This spectacular success led to an escalation of the American space program, and to an undeclared Space Race between the two superpowers. Soviet dog Laika became the first animal in orbit on November 3, 1957. The first orbital flight made by a human being was Vostok 1, carrying Yuri Gagarin on April 12, 1961.

One can distinguish the sub-orbital spaceflight and the orbital spaceflight (cf. Difference between sub-orbital and orbital spaceflights). As for sub-orbital flights, on October 3, 1942 an A4 rocket, a prototype for the German V2 rocket bomb, became the first successful launch of an object into space. The first organisms launched into space were fruit flies and corn seeds aboard a U.S.-launched V2 rocket in July, 1946. Another milestone was achieved on May 17, 2004 when Civilian Space eXploration Team launched the GoFast Rocket on a suborbital flight, the first amateur space flight. On June 21, 2004, SpaceShipOne became the first privately-funded manned spacecraft.

The key people in early space exploration

The dream of stepping into the outer reaches of the Earth's atmosphere was driven by rocket technology. The German V2 was the first rocket to travel into space, overcoming the problems of thrust and material failure. During the final days of World War II this technology was obtained by both the Americans and Soviets as were its designers. Whilst the initial driving force may well have been a weapons race for inter-continental ballistic missiles, this soon became the " Space Race".

• Konstantin Tsiolkovsky, Robert Goddard, Hermann Oberth and Reinhold Tilling laid the groundwork of rocketry in the early years of the 20th century.
• Wernher von Braun, was lead rocket engineer, first working in Germany during World War II before taking American citizenship and working on the first NASA programs. Von Braun was involved through to the Apollo mission landing a man on the Moon.
• The race for space was often led, by Sergei Korolev, whose legacy include both the R7 and Soyuz - which remain in service to this day. Korolev was the mastermind behind the first satellite, first mammal in orbit and first spacewalk. Until his death his identity was closely guarded state secret, not even his mother knew that he was responsible for creating the Russian space programme.

Other key people included:

• Valentin Glushko held role of Chief Engine Designer for USSR. Glushko designed the engines of the early Soviet rockets.
• Vasily Mishin, Chief Designer working under Sergei Korolev and one of first Soviets to inspect the captured German V2 design. Following the death of Sergei Korolev, Mishin was held responsible for the Soviet failure to be first country to place a man on the moon.
• Bob Gilruth, was NASA head of Space Task Force and director of 25 manned space flights. Gilruth was the person who suggested to John F. Kennedy that the Americans take the bold step of reaching the Moon in an attempt to reclaim space superiority from the Soviets.

Criticisms

It is more expensive to perform certain tasks in space with humans rather than by robots or machines. Humans need large spacecraft that contain provisions such as a hermetic and temperature controlled cabin, production of breathable air, food and drink storage, waste disposal, voice- and other communication systems, and safety features such as crew escape systems, medical facilities, etc. There is also the question of the security of the spacecraft as whole; losing a robot is nowhere near as dramatic as human loss, so overall safety of non-human missions isn't as much of an issue. All of these extra expenses have to be weighed against the value of having humans aboard. Some critics argue that those few instances where human intervention is essential do not justify the enormous extra costs of having humans aboard.

Other critics, such as the late physicist and Nobel-prize winner Richard Feynman, have contended that space travel has never achieved any major scientific breakthroughs. However, others counter-argued that there have been many indirect scientific achievements: development of the modern computer, lasers, etc.

Some critics contend that in light of the huge distances in space, human space travel will never be able to do more than achieve an earth orbit or at best visit our closest neighbours in the solar system, and even this will consume large amounts of money and will require complex spacecraft that will accommodate only a handful of people. Supporters of human space travel state that this is irrelevant, because its real value lies in providing a focal point for national prestige and patriotism. They suggest that this was the reason why the Clinton administration cooperated closely with Russia on the International Space Station: it gave Russia something to take pride in, and as such became a stabilizing factor in post-communist Russia. From this point of view, the ISS was a justifiable cash outlay.

Some people also have moral objections to the huge costs of space travel, and point out that even a fraction of the space travel budget would make a huge difference in fighting disease and hunger in the world. However, space exploration itself receives a very small percentage of total government spending (nearly always under 0.5%).

Overall, the public remains largely supportive of both manned and unmanned space exploration. According to an Associated Press Poll conducted in July 2003, 71% of US citizens agreed with the statement that the space program is "a good investment," compared to 21% who did not ( Pollingreport.com).

Timeline of space exploration

Timeline of planetary exploration, Timeline of solar system exploration, Timeline of artificial satellites and space probes

1942-1975

Date	First Success	Country	Mission Name
October 3, 1942	First rocket to reach space (over 100 km)	Germany	V2 rocket, military program
1946	Animal in space (fruit flies)	USA-ABMA	V2
August 21, 1957	Intercontinental ballistic missile (ICBM)	USSR	R-7 Semyorka/SS-6 Sapwood
October 4, 1957	Artificial satellite	USSR	Sputnik 1
November 3, 1957	Animal in orbit (dog)	USSR	Sputnik 2
January 31, 1958	Detection of Van Allen belts	USA-ABMA	Explorer I
December 18, 1958	Communications satellite	USA-ABMA	Project SCORE
September 14, 1959	Probe to Moon	USSR	Luna 2
February 17, 1959	Weather satellite	USA-NASA ( NRL)1	Vanguard 2
August 7, 1959	Photo of Earth from space	USA-NASA	Explorer 6
August 18, 1960	Reconnaissance satellite	USA-Air Force	KH-1 9009
April 12, 1961	Human in orbit	USSR	Vostok 1
March 18, 1965	Extra-vehicular activity	USSR	Voskhod 2
December 15, 1965	Orbital rendezvous2	USA-NASA	Gemini 6A/ Gemini 7
March 1, 1966	Probe to another planet	USSR	Venera 3
July 21, 1969	Human on the Moon	USA-NASA	Apollo 11
April 23, 1971	Space station	USSR	Salyut 1
July 15, 1975	First U.S.-USSR joint mission	USSR USA-NASA	Apollo-Soyuz Test Project

¹Project Vanguard was transferred from the NRL to NASA immediately before launch.
² The Soviet Union had attempted an earlier rendezvous on August 12, 1962; However, Vostok 3 and Vostok 4 were only within five kilometers of one another, and were in different orbital planes. Pravda, however, did not mention this information and indicated that rendezvous had been accomplished.

post-1975

Date	First Success	Country	Mission Name
October 2, 1978	Non-American and non-Soviet in space	USSR	Soyuz 28
April 12, 1981	Reusable manned spacecraft	USA-NASA	STS-1
June 13, 1983	Extra-solar system spacecraft	USA-NASA	Pioneer 10
September 11, 1985	Comet probe	USA-NASA	International Cometary Explorer
April 28, 2001	Space tourist	Russia USA	Soyuz TM-32
June 21, 2004	Privately developed manned spacecraft	USA-MAV	SpaceShipOne 15P

Reusable spacecraft

The first reusable spacecraft, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger when it was lost in January 1986. The Columbia broke up during reentry in February 2003.

The first (and so far only) automatic reusable spacecraft was the Buran (Snowstorm), launched by the USSR on November 15, 1988, although it made only one flight. This spaceplane was designed for a crew and strongly resembled the U.S. Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran.

Per the Vision for Space Exploration, the Space Shuttle is due to be retired in 2010. The orbiter Atlantis (Space Shuttle) may be retired as early as 2008. The Shuttle's human transport role is to be replaced by the partially reusable Crew Exploration Vehicle (CEV) no later than 2014. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a Shuttle Derived Launch Vehicle.

Scaled Composites SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company will build its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic should begin reusable private spaceflight carrying paying passengers in 2008.

Space agencies

While only the United States, Soviet Union/Russian and Chinese space programs have launched humans into orbit, a number of other countries have space agencies which design and launch satellites, conduct space research and coordinate national astronaut programs. In Europe, the European Space Agency serves several nations. Several nations have launched their own satellites including Japan and France.

See also List of space agencies