In
this section
Returning
to Earth
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Returning
to Earth
The orbiter
will hit air molecules and build up heat from friction (approximately
1650 degrees C) by reason that the orbiter moves at about 28,000 km/h.
To protect the orbiter and the astronauts from the heat, the orbiter is
covered with ceramic insulating materials:
- Reinforced carbon-carbon on the wing surfaces and underside
- High-temperature black surface insulation tiles on the tiles on the
upper forward fuselage and around the windows
- White Nomex blankets on the upper payload bay doors, portions of the
upper wing and mid/aft fuselage
- Low-temperature white surface tiles on the remaining areas
The materials described above were designed to absorbed large quantities
of heat. When returing to the Earth through the atmosphere, hot ionized
gases are produced, and it will prevent radio communication with the ground
for about 12 minutes (ionizaton blackout).
Soon, the
orbiter will encounter the main air of the atmosphere and it will be able
to fly like an airplane. The orbiter is being flown by the flight computers
at this point. It will make a series of S-shaped, banking turns to slow
its descent speed when begining final approach to the runway. The commander
flies the shuttle around an imaginary cylinder (18,000 feet or 5,500 m
in diameter) to line the orbiter up with the runway and drop the altitude.
When the orbiter is 2,000 ft (610 m) above the ground, the commander pulls
up the nose to slow the rate of descent. The pilot deploys the landing
gear and the orbiter touches down. The commander brakes the orbiter and
the speed brake on the vertical tail opens up. A parachute is deployed
from the back to help stop the orbiter.
Finally, the whole space shuttle stops.
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Multi
Media
Graphic:
Photo Courtesy
NASA
Photo Courtesy
NASA
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