Computer Sciences

Detecting and responding to incidents with images

When a natural disaster occurs, on-the-ground emergency response teams act quickly to make life-saving decisions. Reducing the response time in such situations is critical to reduce damage impact and save lives. Helpful efforts ...

Computer Sciences

Computer scientist, pixel inventor Russell Kirsch dead at 91

Russell Kirsch, a computer scientist credited with inventing the pixel and scanning the world's first digital photograph, died Aug. 11 at his home in Portland, Oregon, The Oregonian reported. He was 91.

Machine learning & AI

Using the past to predict the future: The case of Typhoon Hagibis

The past is often the window to our future, especially when it comes to natural disasters. Using data from the 2018 floods that struck southwestern Japan to calibrate a machine learning model, researchers from the International ...

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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