page_title: Satellite (artificial)
section_title: Orbits
hierarchical_section_title: Satellite (artificial) / Orbits
caption_attribution_description: Animation showing the motion of a satellite in a geostationary orbit (Green) in relation with a point in the surface of the Earth (Brown), in a 24-hour cycle. Deutsch: geostationäre Umlaufbahn Suomi: Geostationaarinen rata Français&#160;: Point géostationnaire en vert sur l'orbite vis-à-vis un point brun sur la Terre Italiano: Il punto verde e quello marrone sono sempre in linea in un'orbita geostazionaria
context_page_description: A satellite is an object that orbits another object. In space, satellites may be natural, or man-made. The moon is a natural satellite that orbits the Earth. Most man-made satellites also orbit the Earth, but some orbit other planets, or the Sun or Moon. Satellites are used for many purposes. There are weather satellites, communications satellites, navigation satellites, reconnaissance satellites, astronomy satellites and many other kinds. Arthur C. Clarke popularized the idea of the communications satellite.
  The world's first artificial satellite, the Sputnik 1, was launched by the Soviet Union on October 4,1957. This surprised the world, and the United States quickly worked to launch their own satellite, starting the space race. Sputnik 2 was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named Laika. The United States launched their first satellite, called Explorer 1 on January 31, 1958. The UK launched its first satellite in 1962.
  Since then, thousands of satellites have been launched into orbit around the Earth. Some satellites, notably space stations, have been launched in parts and assembled in orbit.
context_section_description: Most of the man-made satellites are in a low Earth orbit (LEO) or a geostationary orbit. To stay in orbit, the satellite's sideways speed must balance the force of gravity. Satellites in low orbit are often less than one thousand kilometers above the ground. Close to the Earth, in LEO, the satellites must move faster to stay in orbit.  Low orbits work well for satellites that take pictures of the Earth. Many do jobs that call for high orbital inclination (they swing above and below the equator), so they can communicate, or look at other areas.  It is easier to put a satellite in low Earth orbit, but the satellite appears to move when viewed from Earth.  This means a satellite dish (a type of antenna) must be always moving in order to send or receive communications with that satellite.  
  Medium orbit works well for GPS satellites - receivers on Earth use the satellite's changing position and precise time (and a type of antenna that does not have to be pointed) to find where on Earth the receiver is.  But constantly changing positions does not work for satellite TV and other types of satellites that send and receive a lot of information.  Those need to be in geostationary orbit.  
  A satellite in a geostationary orbit moves around the Earth as fast as the Earth spins, so from the ground it looks like it is stationary (not moving). To move this way, the satellite must be straight above the equator, and 35,786 kilometers (22,236 miles) above the ground.
caption: A satellite in a geostationary orbit.