Related topics: nasa · space · launch · earth · orbit

Sharing data for improved forest protection and monitoring

Although the mapping of aboveground biomass is now possible with satellite remote sensing, these maps still have to be calibrated and validated using on-site data gathered by researchers across the world. IIASA contributed ...

Warm ocean water attacking edges of Antarctica's ice shelves

Upside-down "rivers" of warm ocean water are eroding the fractured edges of thick, floating Antarctic ice shelves from below, helping to create conditions that lead to ice-shelf breakup and sea-level rise, according to a ...

NASA small satellites can aid hurricane forecasts with GPS

Eight briefcase-size satellites flying in a row may be key to improving forecasts of a hurricane's wind speed—detecting whether it will make landfall as a Category 1 or a Category 5. NASA's Cyclone Global Navigation Satellite ...

A fortress of ice and snow

After only a few days of searching, experts from the MOSAiC expedition have now found a suitable ice floe where they will set up the research camp for their one-year-long drift through the Arctic Ocean. Consequently, one ...

page 1 from 23


In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.

The first artificial satellite, Sputnik 1, was launched by the Soviet Union in 1957. By 2009 thousands of satellites have been launched into orbit around the Earth. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.

Satellites are used for a large number of purposes. Common types include military (spy) and civilian Earth observation satellites, communication satellites, navigation satellites, weather satellites, and research satellites. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include low Earth orbit, polar orbit, and geostationary orbit.

Satellites are usually semi-independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.

This text uses material from Wikipedia, licensed under CC BY-SA