Tag: atmosphere

Geostationary Highway

Posted by Nexus – 21/02/2010

Put a satellite in a circular orbit about 42,000 kilometres from the center of the Earth (36,000 kilometres or so above the surface) and it will orbit once in 24 hours. Because that matches Earth’s rotation period, it is known as a geosynchronous orbit. If that orbit is also in the plane of the equator, the satellite will hang in the sky over a fixed location in a geostationary orbit.

As predicted in the 1940s by futurist Arthur C. Clarke, geostationary orbits are in common use for communication and weather satellites, a scenario now well-known to astroimagers.

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Dark Shuttle Approaching

Posted by Nexus – 17/02/2010

[via APOD]

Click image for full-size picture (6048x4147)

What’s that approaching? Astronauts on board the International Space Station first saw it far in the distance. Soon it enlarged to become a dark silhouette. As it came even closer, the silhouette appeared to be a spaceship. Finally, at just past 11 pm (CST) last Tuesday, the object, revealed to be the Space Shuttle Endeavour, docked as expected with the Earth-orbiting space station.

Pictured above, Endeavour was imaged near Earth’s horizon as it approached, where several layers of the Earth’s atmosphere were visible. Directly behind the shuttle is the mesosphere, which appears blue. The atmospheric layer that appears white is the stratosphere, while the orange layer is Earth’s Troposphere.

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The Astronaut Who Captured a Satellite

Posted by Nexus – 12/01/2010

[via antwrp.gsfc.nasa.gov]

In 1984, high above the Earth’s surface, an astronaut captured a satellite. It was the second satellite captured that mission.

Pictured above, astronaut Dale A. Gardner flies free using the Manned Maneuvering Unit and begins to attach a control device dubbed the Stinger to the rotating Westar 6 satellite. Communications satellite Westar 6 had suffered a rocket malfunction that left it unable to reach its intended high geosynchronous orbit.

Both the previously caught Palapa B-2 satellite and the Westar 6 satellite were guided into the cargo bay of the Space Shuttle Discovery and returned to Earth. Westar 6 was subsequently refurbished and sold.

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