Page 29 - Curriculum Visions Dynamic Book

 The way a Space Shuttle lands.
About an hour before touchdown the orbiter fires its engines to reach an altitude suitable for its descent.
High-speed flight through the air causes leading surface to heat up (speed about 25,000 km/hr).
S turns are made to slow down the orbiter.
The glide path begins, at first in a nose-up position 3,000 km from touchdown.
Very steep descent. 1,000 km from touchdown.
The altitude of the orbiter is changed as it enters the lower atmosphere.
As the orbiter approaches the ground, air brakes and the rudder can be used. At 40 km from the runway the orbiter is still flying at the speed of sound and so creates a sonic boom, which can be heard by people on the ground.
The orbiter lands by following a glide path twenty times faster and seven times steeper than that of an ordinary large airplane. It puts down its undercarriage and lands at 320 km/hr on a runway that is nearly 5 km long. Slowing down is helped by the release of a drag parachute.
Maintenance
The Shuttle has stayed in orbit for up to 17 days. The parts on a Space Shuttle are subject to tremendous stresses and temperature changes, especially on takeoff and landing. As a result, every part of the Shuttle system has to be thoroughly checked before another launch can be made. The loss of Shuttles in the past has made such checks and maintenance an imperative.
composite A material made from solid threads in a liquid matrix that is allowed to set.
sonic boom The noise created when an object moves faster than the speed of sound.
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