{{Mergefrom|Space probe|date=September 2006}} Image:Sputnik_1.jpg '''Unmanned space missions''' are space missions using remote-controlled Spacecraft. The first unmanned space mission was ''Sputnik_I'', launched October_4, 1957 to orbit the Earth. While the terms 'manned' and 'unmanned' are not intentionally gender-specific, some people prefer gender-neutral terms such as '''unpiloted''' or '''uncrewed space missions'''. Space missions where animals but no humans are on-board are considered unmanned missions. Space missions with a mixed human and other animal crew are considered manned missions. Many space missions are more suited to unmanned missions rather than Manned_space_missions, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current manned spaceflight technology, so unmanned probes are the only way to explore them. ==Control== Although generally referred to as remote controlled, some unmanned vehicles have not been. The earliest orbital probes such as Sputnik_I and Explorer_I transmitted one way data to earth; they were not remote controlled. Soon after the first probes, command systems were developed to allow remote control. Unmanned space probes use Telemetry to radio back to earth acquired data and vehicle status information. Most probes have command systems to allow remote control from the ground. However, increased autonomy is important for distant probes where the light travel time prevents rapid decision and control from earth. Newer probes such as Cassini-Huygens and Mars_Exploration_Rover are highly autonomous and can operate independently for periods of time using on-board computers. ==History== Unmanned space missions have been flown by many countries. Most American unmanned missions have been coordinated by the Jet_Propulsion_Laboratory, and European missions by the European_Space_Operations_Centre, part of ESA (the European Space Agency). The ESA has conducted relatively fewer Space_exploration missions in the past (one example is the Giotto_mission, which encountered Comet Halley), but have launched several interplanetary spacecraft in recent years (e.g. Rosetta_space_probe, Mars_Express, Venus_Express). ESA has, however, launched many spacecraft to carry out Astronomy, and is a collaborator with NASA on the Hubble_Space_Telescope. There have been many successful Russian space missions. There have also been a few Japanese, Chinese and Indian missions. ==Types of missions== Unmanned space missions may be divided into two classes: Artificial_satellites, which orbit the Earth, and Space_probes, which leave Earth's orbit to explore other worlds. See the relevant articles for more information. ==See also== * Geosynchronous_satellite * Landings_on_other_planets * List_of_planetary_probes * List_of_unmanned_spacecraft_by_program * Manned_space_mission * Satellite * Space_exploration * Space_observatory * Space_probe * Timeline_of_artificial_satellites_and_space_probes * Timeline_of_first_orbital_launches_by_nationality * Timeline_of_planetary_exploration ==External links== *ESA Unmanned Space Missions *NASA Jet Propulsion Laboratory *Unmanned spaceflight discussion forum *Russia's unmanned moon missions Category:Space_exploration Category:Embedded_systems Category:Unmanned_vehicles Da:Ubemandet_rummission Eo:Kosmosondilo Fr:sonde_spatiale Id:Misi_luar_angkasa_tak_berawak It:Sonda_spaziale Hu:Űrszonda Pl:Sonda_kosmiczna Fi:Avaruusluotain Zh:非载人宇宙飞船