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During the first part of the launch, the shuttle continues to accelerate in order to move above the earth's atmosphere. Approximately one minute into the flight, the shuttle is traveling primarily upwards at the speed of sound (Mach 1). The solid rockets and the shuttle main engines continue to burn their fuel.

About two minutes after lift-off, the solid rockets have used all their fuel. The empty solid rockets are released and pushed away from the shuttle; they parachute back to Earth, while the orbiter and external tank continue upward. The spent solid rockets land in the ocean near Florida, and are picked up and recycled for use on a future shuttle mission. 

When the shuttle is about 60 miles above the Earth, well above the Earth's atmosphere, it begins to change its trajectory to fly more horizontal to the Earth. This allows it to pick up speed. Once it reaches the height its aiming for, and attains the critical speed it needs to stay in orbit (17,500 mph!), the three main engines are shut off. This happens about eight and a half minutes after launch. The nearly empty external tank is then released; it reenters the atmosphere, and disintegrates during re-entry. The orbiter is the only piece that makes it into orbit. 

The orbiter is initially in a rather low, non-circular (elliptical) orbit. It needs to raise its orbit slightly or else it will soon re-enter the atmosphere and return to Earth. The shuttle can no longer use its main engines since the external tank (which contained the fuel they burn) is gone. If it needs to change its orbit, it must rely on a smaller set engines. About forty-five minutes after the main engines are shut off, the orbiter fires these "OMS" (Orbiter Maneuvering System) engines to put into a stable orbit around the Earth.

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