Space probe - Definition and Overview

Unmanned space missions are those using remote-controlled spacecraft. The first such mission was the Sputnik I mission, launched October 4, 1957. Some missions are more suitable for unmanned missions rather than manned space missions, due to lower cost and lower risk factors. Since the early 1970s, most unmanned space missions have been based on space probes with built-in mission computers, and as such may be classified as embedded systems.

Most American unmanned missions have been coordinated by the Jet Propulsion Laboratory, and European missions by ESOC, part of ESA (the European Space Agency). ESA has conducted relatively few space exploration missions (one example is the Giotto mission, which encountered comet Halley). ESA has, however, launched various spacecraft to carry out astronomy, and is a collaborator with NASA on the Hubble Space Telescope. There has been a large number of very successful Russian space missions. There were also a few Japanese missions and the Chinese space program is preparing missions for the future.

Unmanned programs through the ages (first mission year given, if known):

Earth orbit and Lunar missions

Early Earth-orbital missions

• Sputnik program, 1957 - Earth orbit.
• Explorer program, 1958 - Earth orbit.
• Vanguard program, 1959 - Earth orbit.

Earth observation satellites

• Tiros program (1960s).
• Nimbus program (1960s).
• Landsat program.
• TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)

Communication satellites

• Syncom program (1961-1964).
• Telstar (1962).
• Relay program (1963)

Supply vessels

• Progress spacecraft, - resupply vessels to Space stations, 1978-Present.

Lunar exploration

• Luna program - Lunar exploration (1959-1976).
• Ranger program - Lunar hard-landing probes (1961-1965).
• Zond program - unmanned Lunar exploration (1964-1970).
• Surveyor program - Lunar soft-landing probe (1966-1968).
• Lunar Orbiter program - Lunar orbital (1966-1967).
• Lunokhod program - unmanned Lunar Rover probes (1970-1973).
• Muses-A mission (Hiten and Hagoromo) - Lunar orbital and hard-landing probes (1990-1993).
• Clementine mission - Lunar orbital (1998).
• Lunar Prospector - Lunar orbital (1998-1999).
• Smart 1 - Lunar orbital (2003).
• LUNAR-A - lunar orbiter and penetrators, to be launched in 2004
• SELENE - lunar orbiter and lander, to be launched in 2005

Solar System exploration

• Venera program - Venus orbital and landing
• Vega program - Venus and Comet Halley
• Zond program - Moon, Venus, and Mars flyby
• Pioneer Venus project - Venus orbital and landing
• Mariner program - Mercury, Venus and Mars, flyby and orbital
• Pioneer program - Jupiter and Saturn flyby
• Voyager program - Jupiter, Saturn, Uranus and Neptune flyby
• Giotto mission - Flyby of Comet Halley (1986)
• Sakigake probe - Flyby of Comet Halley (1986)
• Suisei probe - Flyby of Comet Halley (1986)
• Galileo probe - Jupiter orbiter and "lander"
• Magellan probe - Venus orbiter
• Cassini-Huygens - Saturn orbiter and Titan lander Huygens; launched 1997
• NEAR Shoemaker - asteroid lander, launched 1996
• Deep Space 1 - comet/asteroid flyby, 1998-2000
• Stardust probe - comet flyby and sample return, launched 1999, expected return 2006
• CONTOUR - comet flyby mission; launch failure in 2003
• Hayabusa - asteroid orbiter, lander and sample return, launched 2003
• Rosetta - comet orbiter and lander (Philae); launched 2004
• MESSENGER - Mercury orbiter, launched 2004
• Dawn - Ceres and Vesta orbiter, to be launched in 2006

Mars Probes

• Zond program - failed flyby probe
• Mars probe program - orbiters and landers
• Viking program - Two orbiters and landers (1974)
• Phobos program - Orbiters/failed Phobos landers
• Mars Pathfinder - Lander and wheeled robot (1996)
• Mars Surveyor '98 program (Mars Climate Orbiter and Mars Polar Lander)
• Mars Odyssey - Mars orbiter
• Mars Observer - failed Mars orbiter
• Mars Express - launch and arrival in Mars orbit in 2003
  • Mars Express Orbiter - Mars orbiter
  • Beagle 2 - failed lander, carried to Mars by Mars Express orbiter (2003)
• Mars Exploration Rovers - A pair of wheeled robots to explore equatorial regions (2004)
• Mars Reconnaissance Orbiter - to be launched 2005
• Mars Science Laboratory - to be launched 2009

See also

• geosynchronous satellite
• List of unmanned spacecraft by program
• manned space mission
• satellite
• space exploration
• space observatory
• Timeline of artificial satellites and space probes
• Timeline of planetary exploration

External links

• ESA Unmanned Space Missions (http://sci.esa.int/home/ourmissions/index.cfm)
• NASA Jet Propulsion Laboratory (http://www.jpl.nasa.gov)