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Space Shuttle Orbiter - A Typical Shuttle Mission

Space shuttles are launched from the NASA John F. Kennedy Space Center in Florida. The orbiter's main engines and the booster rockets ignite simultaneously to lift the shuttle and its crew away from earth and into space. About two minutes after launch, the solid rocket boosters complete their firing sequence and separate from the external tank and, by parachute, fall back into the ocean where they are recovered and used again. The orbiter continues its flight into space with the main engines furnishing ascent power for another eight minutes before they are shut down, just before achieving orbit. The external tank, now empty, separates and falls back into the atmosphere and breaks up over a remote area of the ocean. It is not reusable.

In orbit, space shuttles circle the earth at a speed of about 17,500 mph. Each orbit is about 90 minutes and the crew sees a sunrise or a sunset every 45 minutes. Orbital altitudes for shuttle missions range from as low as 155 miles to as high as 600 miles, based on mission requirements. The flight paths are within a region over earth extending from 57 degrees north to 57 degrees south of the equator. Missions usually last up to 10 days, but the crew has food, fuel, and other supplies to remain in orbit several days longer than planned in case they cannot come back on time due to bad weather at the landing sites.

The crew size varies and can be as many as eight people, although up to 10 can be carried under special conditions. The crew includes the commander, the pilot, and enough mission specialists and payload specialists to carry out the specific mission. Mission specialists are responsible for equipment and resources supporting the payloads during the flight, while the payload specialists are in charge of the specific payload equipment. The mission commander, pilot, and mission specialists are NASA astronauts and assigned by NASA. Payload specialists may or may not be astronauts, and are nominated for the mission by the payload sponsor.

When the mission ends and the orbiter begins to glide back through the atmosphere, special insulation covering the outside portions of the vehicle acts as a heat shield to keep it from getting too hot from air friction and damaged by the heat. Most of the insulation used to protect the orbiter in places where it gets extremely hot is shaped like small tiles. The tiles, about six inches square and made of silica, shed heat so well that one side is cool enough to hold in bare hands while the other side is red hot and withstands temperatures of 2300 degrees (F). Some tiles get damaged during launch or landing and are replaced. The landing speed of the orbiters ranges from 205 to 235 mph, based on the weight of the vehicle.

As soon as the landing occurs, a team of space shuttle recovery operations specialists carefully inspect the orbiter to be sure no gases or fuels are present that may be toxic. This clears the way for the shuttle crew to power down the vehicle while other ground operations personnel begin connecting up ground support equipment and prepare to tow the spacecraft from the landing site to the space shuttle deservicing area at either the Kennedy Space Center in Florida or at Dryden in California.

Hoses from two large mobile units are attached to the orbiter during the towback from the landing site. One is a large air conditioning unit to direct cool air into the orbiter's aft fuselage, payload bay, wings, vertical stabilizer, and orbital maneuvering-reaction control system pods to dissipate heat generated by atmospheric reentry. The other unit is a Freon coolant system to protect the flight crew area and avionics systems from excessive heat during post-landing systems checks.

Related Links:
Space Shuttle Orbiters
NASA's Orbiter Fleet
Space Shuttle Components
Space Shuttle Life
Development History of Space Shuttle
Shuttle Diagrams

Space Shuttle Orbiter | Mir Space Station

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