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

AI crop predictor aids Africa's crisis planning

An artificial intelligence (AI) tool is using satellite remote sensing and machine learning to predict agricultural yields of key crops across Africa, to help mitigate the harms of climate change and other crises, its developers ...

Rocks beneath Antarctic Ice Sheet reveal surprising past

The West Antarctic Ice Sheet is shrinking, with many glaciers across the region retreating and melting at an alarming rate. However, this was not always the case according to new research published last month (April 28) in ...

An improved view of global sea ice

Earth's declining ice is without a doubt one of the clearest signs of climate change. A new high-resolution sea-ice concentration data record has just been released as part of ESA's Climate Change Initiative—providing new ...

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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