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Satellite

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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.

For more information about Satellite, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.


News tagged with satellite

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China is set to launch its second moon orbiter next October, state media have reported

China to launch second lunar probe: state media

Space & Earth / Space Exploration

created 15 hours ago | popularity 5 / 5 (4) | comments 0

China will launch its second moon orbiter next October, state media reported Friday, as it powers ahead with a space programme that has sparked concerns abroad.


Aqua satellite sees Tropical Storm Bongani approaching Mozambique Channel

Aqua satellite sees Tropical Storm Bongani approaching Mozambique Channel

Space & Earth / Earth Sciences

created Nov 25, 2009 | popularity not rated yet | comments 0

NASA's Aqua satellite flew over Cyclone Bongani today and provided some important data that have helped forecasters figure out where the storm is headed, and helped them see that it has changed course.


NASA's Aqua satellite sees Nida explode into a category 5 Super typhoon

NASA's Aqua satellite sees Nida explode into a category 5 Super typhoon

Space & Earth / Earth Sciences

created Nov 25, 2009 | popularity 5 / 5 (2) | comments 0

Typhoon Nida is in a favorable environment that has enabled it to intensify faster and stronger than previously forecast, and has now exploded into a Super typhoon. NASA's Aqua satellite passed over Nida and ...


Ships warned about icebergs headed for New Zealand (AP)

Ships warned about icebergs headed for New Zealand

Space & Earth / Earth Sciences

created Nov 25, 2009 | popularity not rated yet | comments 0

(AP) -- Ships are on alert and maritime authorities are monitoring the movements of hundreds of menacing icebergs drifting toward New Zealand in the southern Pacific Ocean, officials said.


NASA Assessing New Roles for Ailing QuikScat Satellite

NASA Assessing New Roles for Ailing QuikScat Satellite

Space & Earth / Space Exploration

created Nov 24, 2009 | popularity 4 / 5 (1) | comments 1

(PhysOrg.com) -- NASA mission managers are assessing options for future operations of the venerable QuikScat satellite following the age-related failure of a mechanism that spins the scatterometer antenna. ...


Icebergs head from Antarctica for New Zealand (AP)

Icebergs head from Antarctica for New Zealand

Space & Earth / Earth Sciences

created Nov 24, 2009 | popularity 3 / 5 (5) | comments 1

(AP) -- Ships in the south Pacific Ocean have been alerted that hundreds of icebergs believed to have split off Antarctic ice shelves are drifting north toward New Zealand, officials said Tuesday.


New Method to Measure Snow, Soil Moisture With GPS May Benefit Meteorologists, Farmers

Space & Earth / Earth Sciences

created Nov 20, 2009 | popularity not rated yet | comments 1

(PhysOrg.com) -- A research team led by the University of Colorado at Boulder has found a clever way to use traditional GPS satellite signals to measure snow depth as well as soil and vegetation moisture, a technique expected ...


SMOS satellite instrument comes alive

SMOS satellite instrument comes alive (w/ Video)

Space & Earth / Space Exploration

created Nov 19, 2009 | popularity not rated yet | comments 0

The MIRAS instrument on ESA's SMOS satellite, launched earlier this month, has been switched on and is operating normally. MIRAS will map soil moisture and ocean salinity to improve our understanding of the ...


DirecTV to appoint PepsiCo executive as CEO (AP)

DirecTV to appoint PepsiCo executive as CEO

Technology / Business

created Nov 18, 2009 | popularity not rated yet | comments 0

(AP) -- DirecTV Group Inc. is naming the vice chairman of PepsiCo Inc. as its chief executive.


QuikScat and Aqua providing important data on Tropical Storm Anja

QuikScat and Aqua providing important data on Tropical Storm Anja

Space & Earth / Earth Sciences

created Nov 18, 2009 | popularity not rated yet | comments 0

Anja has continued to weaken over the last 24 hours, and NASA's QuikScat satellite has confirmed that the once mighty Category 4 Cyclone is now a tropical storm in the southern Indian Ocean. Two instruments ...


Sezmi offers a new kind of TV service

Technology / Telecom

created Nov 17, 2009 | popularity 4 / 5 (2) | comments 0

Sezmi, a Silicon Valley startup that's pioneering a new type of TV service, is opening up a public test of its system Monday in California.


Terra satellite spots Tropical Cyclone Anja, the first of the southern season

Terra satellite spots Tropical Cyclone Anja, the first of the southern season

Space & Earth / Earth Sciences

created Nov 16, 2009 | popularity 3 / 5 (1) | comments 0

NASA's Terra satellite captured a stunning image of Anja, the first tropical cyclone of the southern Hemisphere cyclone season. When Anja formed on Saturday, November 14, in the Southern Indian Ocean, about ...


TRMM satellite mapped 'Ida the Low's' rainfall from space

TRMM satellite mapped 'Ida the Low's' rainfall from space (w/ Video)

Space & Earth / Earth Sciences

created Nov 16, 2009 | popularity not rated yet | comments 0

The Tropical Rainfall Measuring Mission satellite known as "TRMM" has the ability to measure rainfall from space, and assessed the heavy rainfall from last week's coastal low pressure area, formerly known ...


Penguins and sea lions help produce new atlas

Penguins and sea lions help produce new atlas

Biology / Ecology

created Nov 16, 2009 | popularity not rated yet | comments 0

Recording hundreds of thousands of individual uplinks from satellite transmitters fitted on penguins, albatrosses, sea lions, and other marine animals, the Wildlife Conservation Society (WCS) and BirdLife ...


Investigating muscle repair, scientists follow their noses

Investigating muscle repair, scientists follow their noses

Biology / Cell & Microbiology

created Nov 16, 2009 | popularity 4 / 5 (4) | comments 0

When muscle cells need repair, they use odor-detecting tools found in the nose to start the process, researchers have discovered.