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Space exploration explores space in spacecraft.
Space exploration is the physical exploration of outer space. Space exploration is carried out by both manned and unmanned spacecraft. The development of large liquid-fueled rocket engines during the early 20th century allowed space exploration to become a practical possibility. Space exploration is distinct from the earth-based observation of outer space, known as astronomy, which has occurred for millennia. Common rationales for the pursuit of space exploration include advancing scientific research and ensuring the future survival of humanity. Significant political and ethical questions surround space exploration, and it has often been used as a proxy competition for geopolitical rivalries such as the Cold War.
The early era of space exploration was driven by a space race between the Soviet Union and the United States; the launch of the first man-made object to orbit the Earth, the USSR's Sputnik 1, on October 5, 1957, and the first Moon landing by the American Apollo 11 craft on July 20, 1969 are often taken as the boundary for this initial period. The Soviet Union achieved many of the first milestones, including putting the first man in space, Yuri Gagarin aboard Vostok 1 in 1961, and completing the first spacewalk (by Alexei Leonov in 1965). In 1971, the Soviets launched the first space station, Salyut 1.
After the first 20 years of exploration, focus shifted from one-off flights to renewable hardware, such as the Space Shuttle program, and from competition to cooperation as with the International Space Station. From the 1990s onwards, private interests began promoting space tourism. Larger government programs have advocated manned missions to the Moon and possibly Mars sometime after 2010.
Space exploration's first orbital flights.
The first successful orbital launch was of the Soviet unmanned Sputnik I mission on October 4, 1957. The satellite weighed about 83 kg (184 pounds), and is believed to have orbited Earth at a height of about 250 km (150 miles). It had two radio transmitters (20 and 40 MHz), which emitted "beeps" that could be heard by any radio around the globe. Analysis of the radio signals was used to gather information about the electron density of the ionosphere, while temperature and pressure data was encoded in the duration of radio beeps. The results indicated that the satellite was not punctured by a meteoroid. Sputnik 1 was launched by an R-7 rocket. It incinerated upon re-entry on January 3, 1958.
This success led to an escalation of the American space program, which unsuccessfully attempted to launch Vanguard 1 into orbit 2 months later. On January 31, 1958, the US successfully orbited Explorer I on a Juno rocket. In the meantime, the Soviet dog Laika became the first animal in orbit on November 3, 1957.
First human in space.
The first manned spaceflight was Vostok 1, carrying 27 year old cosmonaut Yuri Gagarin on the historic date April 12, 1961. The spacecraft completed one orbit around the globe, which lasted about 1 h 48 min. Currently this milestone date is celebrated as Cosmonautics Day (Space Day).
Gagarin's flight resonated around the globe not only showing the then-superiority of the Soviet space program but opening an entirely new era in space exploration - manned space flights. The U.S. would launch its first man into space within a month of Gagarin's flight with the first Mercury flight, by Alan Shepard. However, orbital flight was not achieved until John Glenn's flight nearly a year later. China would launch its first taikonaut into space 42 years later, with the flight of Colonel Yang Liwei aboard the Shenzhou 5 spacecraft.
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. The initial driving force for further development of the technology was a weapons race for inter-continental ballistic missiles (ICBMs) to be used as long-range carriers for fast nuclear weapon delivery, but in 1961 when USSR launched the first man into space, the US declared itself to be in a "space race" with Russia.
Other key people included in space exploration:
Criticisms of space exploration.
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, compared to much more costly endeavors, like military actions, 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.
Some supporters of Space Explorations, such as Robert Zubrin, have criticized ideas about in orbit assemblies, and argues for a direct approach for human settlement of Mars called Mars Direct.
Timeline of space exploration. 1942-1975.
1Project Vanguard was transferred from the NRL to NASA immediately before launch.
Space exploration post-1975.
In addition, virtually all manned duration records have been set by the USSR, due largely to their Salyut/Mir series of space stations.
Reusable spacecraft in space exploration.
The first partially reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963. The first partially reusable orbital 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 due mainly to its old age and high cost of program reaching over a billion dollars per flight. 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 exploration and space colonization.
Space colonization, also called space settlement and space humanization, is the permanent autonomous (self-sufficient) human habitation of locations outside Earth, specially in natural satellites or planets (Moon, Mars...).
Space exploration 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 India, Japan and France.
Space exploration unmanned missions.
Animals in space.
Human space exploration.
Recent and future developments of space exploration.
Other space exploration.
More About Space Exploration And Missions.
Dec 23, 2005 - An Ariane 5 rocket blasted off from the Guiana Space Centre on December 21, carrying two satellites into orbit: ESA's MSG-2 satellite and India's INSAT-4A telecommunications satellite. Ground tracking stations received good telemetry information from both satellites, indicating they were put into their proper orbits. ESA's MSG-2 will provide high-resolution images of the Earth's weather activity, while INSAT-4A will provide broadcast television and high-speed data services above the Indian subcontinent.
Dec 22, 2005 - After years in space, and having successfully collected samples from a comet, NASA's Stardust spacecraft is almost home. If all goes well, the spacecraft will release its sample capsule on January 15, 2006. Four hours after it's released, the sample container will enter the Earth's atmosphere at a velocity of 46,440 kilometers per hour (28,860 miles per hour). The container will land at the US Air Force Utah Test and Training Range, southwest of Salt Lake City.
Nov 17, 2005 - An Ariane 5 rocket blasted off Thursday from Kourou, French Guiana carrying two satellites: Spaceway 2 broadcast satellite for DIRECTV, and the Telcom 2 communications satellite for PT Telekomunikasi Indonesia Tbk. The combined weight of the two satellites was more than 8,000 kg (17,500 pounds), making this the heaviest double payload ever launched.
Oct 11, 2005 - ESA officials have confirmed that the Cryosat mission smashed into the Arctic ocean minutes after launch on Saturday. It was launched on board a Rockot vehicle - a converted SS-19 intercontinental ballistic missile - from the Plesetsk Cosmodrome in northern Russia. The 135m euro satellite was designed to monitor ice thickness around the planet. Another version of the satellite may be constructed.
Oct 11, 2005 - After 17 months of productive data collection, NASA's Gravity Probe B satellite has gathered all the data it needs to pronounce Einstein right or wrong. The probe was launched in April 2004, with four spherical gyroscopes designed to test two of Einstein's predictions about General Relativity: how the Earth's gravity warps space, and how its rotation drags space around with it. Scientists will now spend about a year analyzing the data before presenting their conclusions.
Sep 8, 2005 - NASA and Sandia National Laboratories have been using a powerful solar tower to test new spacecraft materials. The tower reflects and focuses the Sun's radiation to blast spacecraft shields with the equivalent of 1,500 suns. This research effort is tied to a potential future mission to Saturn's moon Titan, which orbits in a very high-radiation environment. They have mimicked Titan's nitrogen-rich atmosphere for the tests, and the shield materials seem to have passed with flying colours.
Jul 28, 2005 - Sailing through space on nothing but photons from the Sun is a nice dream, but we're still years away from the reality. NASA took their next step in June, however, when they tested a 20-metre (66-foot) prototype solar sail at their Plum Brook research facility. They successfully deployed the sail using an inflatable boom designed to unfurl the sail from a box the size of a suitcase and then keep it rigid in space.
May 24, 2005 - NASA's Voyager 1 spacecraft has traveled so far in our solar system that it's reached the heliosheath. This is an area just past the termination shock region, where the solar wind crashes into the thin interstellar gas of the galaxy. It was difficult to detect exactly when Voyager 1 passed through the termination shock and into the heliosheath, because we have no data about interstellar space yet, just calculations.
Apr 21, 2005 - When NASA's Genesis smashed into the desert last year, mission controllers and scientists feared the worst for the spacecraft's fragile particle collectors. However, after having examined them carefully, it appears that plenty of useful science will be possible with the collected material. The four solar wind collectors, in an instrument called the concentrator are in excellent condition and should help scientists understand how the solar system formed.
Apr 18, 2005 - NASA's DART mission, which launched on Friday to test automated docking techniques, was prematurely shut down on Saturday when the spacecraft ran out of fuel. DART launched perfectly on board a Pegasus XL rocket and reached within 90 meters of its target, an inactive satellite already in orbit. It was supposed to make several close approaches to the satellite, but it didn't even have enough propellant for one pass. Mission controllers aborted the mission and fired its deorbit rockets to put it into a decaying orbit where it will burn up. An investigation team has been assigned to figure out what went wrong.
Apr 13, 2005 - When it comes to using advanced technology, NASA sometimes faces a self-defeating loop: they can't take the risk of flying new technology in space unless it's already flown successfully in space. The New Millennium Program circumvents that loop by testing and validating the performance of leading-edge technologies in space so that they can be used in future operational science missions. Examples of upcoming New Millennium missions include advanced solar arrays, fault-tolerant high speed computers, a Nanosat (microsatellite) constellation, and perhaps, a solar sail.
Apr 12, 2005 - Today NASA has 55 active mission control teams monitoring ongoing spacecraft and station missions - 13 associated with missions extended beyond original planning. Soon there may be seven less. By October of this year, we could be turning a deaf ear to data collected by one of the most successful NASA programs of all times. For even as Voyager 1 and 2 are poised to enter the interstellar realm, budget-minders in our nation's capital may have already sealed the fate on a pair of craft that could provide important information about our solar system - and beyond - for the next 15 years.
Apr 5, 2005 - When he developed his General Theory of Relativity, Einstein predicted that the motion of large masses should create ripples in spacetime called gravity waves. Now 100 years after his theory, a precise instrument is being prepared that should be able to find out if he was right or not. A joint ESA/NASA mission called LISA (Laser Interferometric Space Antenna) will launch in 2012. It will consist of three spacecraft flying 5 million km apart, which measure their distances from each other precisely. LISA should be able to detect black holes and neutron stars as well as echos from the Big Bang.
Mar 30, 2005 - Launched from "Cape Kennedy" just 13 months of one another in 1972/73, Pioneer 10 and 11 are still up there though no longer kicking. But well before last phone home (in 2003 and 1995 respectively), the notes each pair played had changed pitch unexpectedly - they were slowly losing speed. Could the Pioneering Pair have been feeling a bit in the "dark" (as in "dark matter" or "dark energy")? Were they having a "Solar Quadrupole" moment? Could n-dimensional "branes" be behind it? Or has "back-gravity" from behind the Sun played a role? Before things get too exotic, maybe there's a simpler explanation.
Mar 5, 2005 - The European Space Agency's Rosetta spacecraft swept past the Earth and Moon on Friday, gaining a gravity speed boost on its 10-year journey to reach Comet 67P/Churyumov-Gerasimenko. At its closest point, Rosetta passed just 1954 km (1214 miles) above the Pacific Ocean before speeding back off into space. This flyby allowed controllers to rehearse their procedures on a "fake asteroid" (the Moon), as Rosetta will visit two asteroids as part of its mission. Rosetta will make two more visits to Earth and one to Mars before its trip is complete.
Jan 27, 2005 - NASA has chosen to fund a new spacecraft, called the Interstellar Boundary Explorer (IBEX), to study the edge of the Solar System, where the solar wind from the Sun interacts with interstellar particles. IBEX will launch in 2008, and take a highly elliptical orbit that keeps it away from the influence of the Earth's magnetosphere. It's equipped with two neutral atom imagers designed to spot interstellar particles as they interact with the outgoing solar wind. IBEX will also study galactic cosmic rays that pose a radiation risk to space explorers.
Jan 12, 2005 - NASA's Deep Impact spacecraft lifted off from Florida's Cape Canaveral on Wednesday, beginning a six-month cruise to smash a hole in a comet. If everything goes well, the spacecraft will reach Comet Tempel 1 on July 4, 2005 deploying an impactor that will carve out a large crater. The resulting explosion should be the equivalent of 4 tonnes of TNT, and could be bright enough to be seen with the unaided eye back on Earth. Deep Impact will be watching the explosion from a safe distance of 500 km, and should get a unique view of the comet's composition, and what lies under its surface.
Dec 14, 2004 - Engineers are making the final preparations for the launch of NASA's Deep Impact spacecraft, due to lift off from Cape Canaveral on January 12, 2005. The spacecraft will make a six-month journey to reach the nucleus of Comet Tempel 1, and then deploy a probe that will crash into it at 37,000 km/h (23,000 mph). The 1-metre square copper probe will completely vapourize, and should carve out a hole the size of the Roman Coliseum, which Deep Impact will be able to study as it passes the comet shortly afterwards. The impact will also be recorded by Hubble, Spitzer, Chandra, and dozens of Earth-based observatories.
Nov 20, 2004 - After several days of delays, NASA's Swift observatory was finally launched Saturday at 1716 UTC (12:16 pm EST) atop a Boeing Delta II rocket. Swift's job will be to scan the heavens for elusive Gamma Ray Bursts (GRBs), which astronomers think could be the birth cries of new black holes. GRBs are short-lived, lasting only seconds - a few minutes at most. Swift can locate an explosion, and turn the entire spacecraft in about a minute to focus sensitive instruments on the fading afterglow. If everything works as planned, the spacecraft should be able to find more than 100 of these explosions every year.
Nov 17, 2004 - NASA's Swift spacecraft is sitting on top of a Boeing Delta II rocket at Florida's Cape Canaveral, waiting for technical difficulties to be resolved with a piece of electronic equipment on the rocket. If everything goes well, Swift will lift off on Thursday, and head into space to search for the most powerful explosions in the Universe: Gamma Ray Bursts (GRBs), which could be the birth cries of new black holes. The observatory's gamma ray detector scans the sky looking for these explosions. When it finds them, the whole spacecraft will turn to focus on the source within 70 to 100 seconds, and analyze it with a suite of other instruments.
Links For Space Exploration And Missions.Gravity Probe B - The Relativity Mission - Relativity gyroscope experiment developed by NASA & Stanford University to test two extraordinary, unverified predictions of Einstein's general theory of relativity.
Lunar Prospector - Lunar Prospector was launched to the Moon, Jan 6th, 1998 and ended on July 31 1999 with a controlled crash.
NASA Discovery Program - Discovery is a series of lower cost, highly focused science investigations designed to enhance our understanding of the solar system.
Project Starshine Student Satellite - The second of eleven Starshine student satellites is under construction for a Space Shuttle launch in 2001. Get involved!
Space Horizons - The up-to-date Calendar of all major Spaceflight Events in the coming years.
Thermal Emission Spectrometer Project Homepage - the home of the Mars Global Surveyor's Thermal Emission Spectrometer (TES) instrument
Advanced Camera for Surveys
ASU Planetary Geology Group
Cassini Home Page
Comet Nucleus Tour (CONTOUR)
Galileo / Near Infrared Mapping Spectrometer
Galileo Home Page
Global Geospace Science Program
GOES Project Science
Gravity Probe B
JPL Mission and spacecraft Library
Mars Global Surveyor
Mars Global Surveyor
Mars Polar Lander
Mars Volatiles and Climate Surveyor
NASA Genesis Mission
NASA Spartan Homepage
Near Earth Asteroid Rendezvous
Small Explorer's Website
Space Inferometry Mission
Tel Aviv University UV Explorer
The Official SwRI IMAGE Mission Web Site
Voyager Project Home Page
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