Category FLIGHT and M ОТІOIM

Military pilots fly with the U. S. Air Force, U. S. Navy, U. S. Marine Corps, U. S. Army, U. S. Coast Guard, and the Air National Guard. In the U. S. Air Force, the Air Education and Training Command (AETC) is based at Randolph Air Force Base near San Antonio, Texas. Personnel hoping to become pilots receive up to 25 hours of initial flight training from civilian instructors. Selected candidates move on to further training by military instructors. Student pilots learn to fly on fairly slow training airplanes, such as the turboprop T-6II, moving up to the twin-jet T-37, and then to a supersonic jet such as the T-38.

All students learn basic flight skills. Then they are selected for one of sever­al advanced training tracks, depending on the type of aircraft they will fly. Helicopter pilots, for example, receive
special training, on the UH-1 Huey heli­copter. Student airlift (transport) and tanker pilots train on the T-1A Jayhawk, and others fly the T-44 to learn how to pilot a multi-engine, turboprop airplane such as the C-130 Hercules.

Pilots complete their training at U. S. Air Force bases around the country. For example, fighter pilots qualifying from the T-38 course at Randolph Air Force Base go on to fly the F-15 Eagle at Tyndall Air Force Base, Florida, or the F-16 Fighting Falcon at Luke Air Force Base, Arizona. On completion of their military service, many pilots continue to fly as civilian pilots.

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SEE ALSO:

• Barnstorming • Bleriot, Louis

• Coleman, Bessie • Curtiss, Glenn

• Earhart, Amelia • Lindbergh,

Charles • Night Witches

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Many home security systems have motion detectors that sense when someone is moving around in a room. Some of these detectors work by picking up the heat of the person’s body, but others use radar. They flood the room with microwaves that bounce back to the detector. If someone enters the room, the steady pattern of reflec­tions is disturbed, and an alarm sounds.

Some of the cameras used to monitor the speed of vehicles on highways work by radar. The radar system measures the speed of the vehicles. If a vehicle is moving faster than the speed limit, the radar system triggers a camera that photographs the car, includ­ing its license plate, so it can be traced to the speeding owner.

Archaeologists use a variety of methods to map structures under­ground and ground-penetrating radar is one of these methods. Radar can probe down to 33 feet (10 meters) deep and show buried features of ancient buildings such as walls and floors.

Science satellites carry out a range of tasks to observe objects and phenomena in space. They have transformed many scientists’ views of the universe. Science satellites’ instruments often measure radiation in various forms. IRAS (Infrared Astronomical Satellite) was launched in 1983. In its ten-month lifespan, it discov­ered 20,000 galaxies (including a new kind called a starburst galaxy), 130,000 stars, and a comet. In 1999, the Space Shuttle Columbia launched an X-ray observatory named Chandra. It has an unusual elliptical orbit that brings it to

SPACE JUNK

Old satellites and leftover pieces of satellite launch vehicles end up as trash drifting in space. Space junk is heaviest at a height of around 530 miles (850 kilometers), where most satellites orbit. After a half-century of space launches, there is now a lot of space junk. Scientists have recorded at least 11,000 objects larger than 4 inches (10 cen­timeters) in diameter. The junk includes used-up rocket stages, tools lost by astronauts, and lumps of solidified fuel. Space junk is a potential hazard, since a lump of fist-size debris, traveling at more than 21,000 miles per hour (33,800 kilometers per hour), can make a serious hole in an expensive spacecraft.

within 6,000 miles (9,650 kilometers) of Earth and then swings out to 86,000 miles (about 138,400 kilometers)-about a third of the way to the Moon. Each orbit takes 64 hours. Being so far out means Chandra keeps clear of the belts of charged particles that surround Earth and so provides astronomers with longer peri­ods of clear observation time.

SEE ALSO:

• Gravity • Rocket • Space Probe

• Space Race

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