Space Shuttle Landing Wallpaper 1024 x 768
NASA's Space Shuttle, officially called the Space Transportation System (STS), is the spacecraft currently used by the United States government for its human spaceflight missions and is scheduled to be retired from service in 2010. At launch, it consists of a rust-colored external tank (ET), two white, slender Solid Rocket Boosters (SRBs), and the orbiter, a winged spaceplane which is the space shuttle in the narrowest sense. The orbiter carries astronauts and payload such as satellites or space station parts into low earth orbit, into the Earth's upper atmosphere or thermosphere. Usually, five to seven crew members ride in the orbiter. The payload capacity is 22,700 kilograms (50,000 lb). When the orbiter's mission is complete it fires its Orbital Maneuvering System (OMS) thrusters to drop out of orbit and re-enters the lower atmosphere. During the descent, the shuttle orbiter decelerates from hypersonic speed primarily by aerobraking and then for the landing phase it acts as a glider, making a completely unpowered ("deadstick") landing. Landing sites conditions permitting, the space shuttle will always land at Kennedy Space Center; however, if the conditions make landing there unfavorable, the shuttle can touch down at Edwards Air Force Base in California or at other sites around the world. A landing at Edwards means that the shuttle must be mated to the Shuttle Carrier Aircraft, and returned to Cape Canaveral, costing NASA an additional 1.7 million dollars. Space Shuttle Columbia (STS-3) also landed once at the White Sands Space Harbor in New Mexico, but this is viewed as a last resort, as NASA scientists believe that the sand could potentially damage the shuttle's exterior.