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TYPICAL LANDING 101



SUBMITTED BY ARTHUR N1ORC - AMSAT A/C #31468

    
MISSION INFORMATION    
Landing 101

Follow along with the landing! Whether the space shuttle lands at the 
prime landing site at Kennedy Space Center in Florida or its backup 
landing site at Edwards Air Force Base in California, the Virtual Launch 
Control Center is the only place online to get breaking information 
directly from NASA.

Orbiter Atlantis lands at Kennedy Space Center after mission STS-110When 
it is time to return to Earth, the orbiter is rotated tail-first into 
the direction of travel to prepare for another firing of the orbital 
maneuvering system engines. This firing is called the deorbit burn. Time 
of ignition (TIG) is usually about an hour before landing. The burn 
lasts three to four minutes and slows the shuttle enough to begin its 
descent.



Below are some of the key events that take place at each milestone prior 
to touchdown.

Note: Times, distances and speeds can vary according to a variety of 
factors such as mission inclination, trajectory and glide slope.

TIG-4 hours
Crew members begin preparations for landing. The orbiter's onboard 
computers are configured for entry, as is the hydraulic system that 
powers the orbiter's aerosurfaces -- its rudder speed brake and wing 
elevons.

TIG-3 hours
The payload bay doors are closed. Mission Control gives the commander 
the "go" for Ops 3, the portion of the orbiter's flight control software 
that manages entry and landing.

TIG-2 hours
Starting with the commander and pilot, the flight crew members don their 
orange launch and entry suits and strap into their seats.

Aerial photo of the Shuttle Landing Facility at Kennedy Space 
CenterImage to right: This aerial photo shows the runway at Kennedy 
Space Center's Shuttle Landing Facility at left. In the foreground is 
the parking apron with the orbiter mate/demate tower, the hangar and 
other storage facilities, and the tow-way stretching from the runway to 
the lower right. The control tower is located in a grassy area farther 
north, near the runway's midpoint. Image credit: NASA/KSC--SEE 
http://www.nasa.gov/mission_pages/shuttle/launch/landing101.html

TIG-1 hour
Mission Control gives the "go" for deorbit burn.

DEORBIT BURN
The orbiter and crew are officially on their way home.

During reentry and landing, the orbiter is not powered by engines. 
Instead, it flies like a high-tech glider, relying first on its steering 
jets and then its aerosurfaces to control the airflow around it.

Landing-30 minutes
Roughly half an hour after the deorbit burn, the orbiter will begin to 
encounter the effects of the atmosphere. Called entry interface, this 
point usually takes place at an altitude of about 80 miles, and more 
than 5,000 statute miles from the landing site.

Early in reentry, the orbiter's orientation is controlled by the aft 
steering jets, part of the reaction control system. But during descent, 
the vehicle flies less like a spacecraft and more like an aircraft. Its 
aerosurfaces -- the wing flaps and rudder -- gradually become active as 
air pressure builds. As those surfaces become usable, the steering jets 
turn off automatically.

To use up excess energy, the orbiter performs a series of four steep 
banks, rolling over as much as 80 degrees to one side or the other, to 
slow down. The series of banks gives the shuttle's track toward landing 
an appearance similar to an elongated letter "S."

As the orbiter slices through the atmosphere faster than the speed of 
sound, the sonic boom -- really, two distinct claps less than a second 
apart -- can be heard across parts of Florida, depending on the flight path.

Landing-5 minutes
The orbiter's velocity eases below the speed of sound about 25 statute 
miles from the runway. As the orbiter nears the Shuttle Landing 
Facility, the commander takes manual control, piloting the vehicle to 
touchdown on one of two ends of the SLF.

As it aligns with the runway, the orbiter begins a steep descent with 
the nose angled as much as 19 degrees down from horizontal. This glide 
slope is seven times steeper than the average commercial airliner 
landing. During the final approach, the vehicle drops toward the runway 
20 times faster than a commercial airliner as its rate of descent and 
airspeed increase. At less than 2,000 feet above the ground, the 
commander raises the nose and slows the rate of descent in preparation 
for touchdown.

Landing-15 seconds
The main and nose landing gear are deployed and locked in place.

Touchdown!
The orbiter's main landing gear touches down on the runway at 214 to 226 
miles per hour, followed by the nose gear. The drag chute is deployed, 
and the orbiter coasts to a stop.

For more detailed information, visit:
+ Fact Sheet: Landing the Space Shuttle Orbiter
+ Space Shuttle Reference Manual: Mission Events Summary
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