Category FLIGHT and M ОТІOIM

The International Space Station (ISS) began to take shape in Earth orbit in 1998. It has been permanently manned by teams of visiting astronauts since November 2000. Still under construc­tion, it is due to be completed by the year 2010. Progress on the ISS was held up by the grounding of the Space Shuttles after the loss of Columbia in 2003. With Shuttle flights resumed in 2006, however, the remaining modules of the ISS should be in place on sched­ule. They include the European module Columbus along with the Japanese mod­ule Kibo. Russia has plans to launch a third module, the Multi-purpose Laboratory Module (MLM) in 2009, using its Proton rocket. The ISS presently can accommodate a crew of three, and it cir­cles the Earth at an average speed of 17,165 miles per hour (27,618 kilometers per hour). When fully assembled, the space station will be a fully functional space laboratory above Earth, crewed by international scientists.

The space station is an example of international cooperation. Five national space agencies are involved in its construction and use: NASA (United States), the Canadian Space Agency, the European Space Agency, the Russian Federal Space Agency, and the Japanese Aerospace Exploration Agency. The Brazilian and Italian space agencies also are taking part.

Like many other space projects, the ISS represents a compromise. In the 1980s, the United States, Europe, and the Soviet Union (now Russia) all had plans to establish their own space stations, but high cost forced them to pool resources. Even so, the ISS is likely to cost more than $100 billion by the time it is completed.

Future ISS-linked developments include the European Automated Transfer Vehicle (ATV) and a similar spacecraft being built by Japan. There will be new passenger-carrying shuttle vehicles, such as the Space X Dragon (2009) and the Russian Kliper (2012). Europe’s first ATV is designed to be launched by an Ariane 5 rocket and to dock automatically with the space sta­tion to deliver fuel and other supplies. At the end of its stay, the ATV will be loaded with trash and sent on a deliber­ately destructive reentry into Earth’s atmosphere, where it will burn up and disintegrate. Six more ATVs will be launched, at eighteen-month intervals, to visit the space station.

Radio signals from the satellites travel at the speed of light. It takes less than one-

tenth of a second (only 65 to 85 milli­seconds) for a radio signal to travel from a GPS satellite to a GPS receiver on Earth. A GPS receiver picks up the signals and measures the time that they took to travel from the satellites. It then multiplies these times by the speed of light to calculate the distance to each satellite. Knowing how far it is from the satellites enables the receiver to pinpoint its own location.

The satellites transmit on two differ­ent radio frequencies, L1 and L2. The signals may slow down a little as they travel through the atmosphere, and this can cause an error in calculating a posi­tion. Because of this, the simplest GPS receivers are accurate to within about 30 to 60 feet (about 9 to 18 meters). More advanced receivers can correct errors caused by the atmosphere, and so they are more accurate. These receivers can calculate their position to within about 15 to 30 feet (about 5 to 10 meters).

A helicopter has four main controls: throttle, cyclic control, foot controls (to control torque), and collective. The pilot uses the throttle to control the speed of the engine. By moving the cyclic control lever or control column, the pilot can alter the tilt of the rotor blades. For example, pushing the stick forward tilts the rotor forward, and the helicopter flies forward.

The pilot uses foot pedals to turn the helicopter by altering the pitch of the tail rotor blades, which swings the tail around. The collective pitch stick or lever is used to control the angle, or pitch, of the rotor blades. This action affects the amount of lift generated and thus makes the helicopter fly up or down, or causes it to hover.

In 1930, scientists at Gottingen University, Germany, tried to figure out how a bumblebee could actually fly. When they analyzed their studies and
calculations, these experts concluded that—from a scientific point of view—the bumblebee should not actually be capa­ble of flight. It was not the right shape. More recently, scientists have used robot insects to study the mechanics of insect flight. They created large-scale model insect wings, stuck them in a tank of thick oil, and used a motor to beat the wings up and down. Flapping slowly in the oil, the model wings acted much as tiny wings do when they are flapping very fast in the air.

Such experiments have shown that an insect can use three kinds of wing movements to perform amazing maneu­vers. When a fly is trying to dodge a predator, such as a human trying to swat it, the insect can change direction in thirty-thousandths of a second.

Three Maneuvers

The first movement, unique to insects, is known as delayed stall, which means that the insect wing sweeps forward at a high angle. The insect wing cuts through the air at a steeper angle than an air­plane wing. An airplane at this stage would stall, losing lift and increasing drag, and it would most likely crash. In an insect, however, the steep angle pro­duces a vortex (like a whirlpool in the air) above the wing, cre­ating extra lift.

The second insect technique is rotation­al circulation. Toward the end of its stroke,

О A swarm of locusts surrounds a farmer in the Philippines. Locusts can destroy entire crops of rice and sugar.

О The mosquito belongs to the same insect family as a housefly. Instead of rear wings, mosquitoes and flies have two halteres to help them fly.

the insect wing rotates backward. This produces backspin, which in turn pro­duces extra lift.

The third insect trick is wake capture, which gains extra lift by recapturing energy lost in the wake (the disturbed air left behind the flying insect). As the wing moves through the air, it creates turbulent air behind it. By rotating the wing before starting the return stroke, the insect captures some of this air, and the energy within it, for extra lift.

Acrobatic insects, such as the hover – fly, make use of rotational circulation and wake capture but do not often use delayed stall. Butterflies do not appear
to use any of these three techniques very much. They fly more like birds, gliding or flapping their wings in a less complex fashion. Flies have a pair of special balance organs instead of rear wings. Called halteres, they are shaped some­what like tiny clubs. These organs help give flies their remarkable flying skills.

he John F. Kennedy Space Center on Merritt Island in Florida is the spaceport of the National Aeronautics and Space Administration (NASA). The center has been the hub of U. S. space exploration since the 1960s. From the space center, NASA launched some of the most historic missions of the space age. Today, the Kennedy Space Center is the base for Space Shuttle missions and is also home to the Constellation Program-a plan to build a
new generation of spacecraft to take astronauts to the Moon and Mars.

Date of birth: February 4, 1902.

Place of birth: Detroit, Michigan.

Died: August 26, 1974.

Major contribution: First person to fly nonstop and solo across the Atlantic Ocean.

Awards: Distinguished Flying Cross;

Medal of Honor.

f all the heroes of early aviation, Charles Lindbergh was perhaps the most beloved. His nonstop solo flight across the Atlantic Ocean in 1927 made him a hero around the world. Lindbergh made other contributions to the field of aviation, but he also suffered from personal tragedy and controversy.

Early Years

As a child, Charles Lindbergh learned to love the outdoors, became fascinated by machinery, and dreamed about flying. Alhough intelligent, Lindbergh was not a good student. He began attending the University of Wisconsin but left after a few semesters of poor grades.

About the same time, Lindbergh went up in an airplane for the first time. He immediately signed up for lessons. Once he gained a pilot’s license, Lindbergh began flying as a barnstormer (a type of stunt pilot). In 1925, Lindbergh joined the Robertson Aircraft Company of St. Louis, Missouri, which had a contract to carry airmail. Lindbergh flew the St. Louis-to-Chicago route, and the job pro­vided him with superb training. He had

to take his aircraft aloft in all kinds of weather, and he regularly flew after dark.

Trident, a nuclear weapon, is the U. S. Navy’s submarine-launched ballistic missile (SLBM). A Navy submarine can carry up to twenty-four Trident missiles. The latest Trident missile model, the Trident II (D5), can hit targets 4,600 miles (7,400 kilometers) from wherever it is launched. The British Royal Navy is also armed with Trident.

Nuclear missiles such as Trident are deterrent, or strategic, weapons. A deter­rent is so terrible that its mere existence deters an enemy nation from attacking. A nuclear attack would trigger an unstoppable, devastating nuclear retali­ation. This policy is sometimes known as mutually assured destruction, or MAD.

Most missiles have one warhead—the exploding part in the missile’s nose. Strategic missiles often have several warheads that can be aimed at different targets. The warheads are located on a part called a bus. The bus is blasted into

О This drawing shows a typical multiple independently targetable reentry vehicle (MIRV)— the multiple warhead of a strategic missile.

the upper atmosphere. Its guidance system aims it at the first target and releases one warhead. The warhead heads back to Earth and falls on that target. Meanwhile, small rocket thrusters have turned the bus to aim at another target and released another warhead. Trident can carry up to twelve warheads. This type of warhead is called a MIRV, which stands for multiple independently targetable reentry vehicle.

On October 1, 1958, Congress created a new organization “to provide for research into the problems of flight with­in and outside the Earth’s atmosphere, and for other purposes.” This new organ­ization was the National Aeronautics and Space Administration, or NASA.

NASA had broad goals linked to the needs of national defense and the advancement of U. S. space science. It was hoped, through the direction of a single agency, that NASA would avoid the duplication of effort that had occurred through separate U. S. Air Force, Army, and Navy rocket programs.

When NASA came into being on October 1, 1958, it absorbed NACA’s employees (there were by then 8,000 of them) and its three major research labo­ratories: Langley, Ames, and Lewis. NASA also acquired the facilities operat­ed by the Jet Propulsion Laboratory (JPL). This lab, run by the California Institute of Technology for the U. S. Army and the U. S. Army Ballistic Missile Agency, was where rocket pioneer Wernher von Braun and other engineers were at work on long-range missiles.

The military began to realize the tactical importance of parachutes for landing both troops and supplies from aircraft. Airborne units were formed and used in World War II (1939-1945). The Germans used paratroops to attack Crete in 1941. In 1944, thousands of Allied airborne troops were dropped from the skies above Europe during the D-Day and Arnhem assaults. Transport planes also parachuted supplies to soldiers and dropped food and medicines to civilians.

О The 150-foot (46-meter) solid rocket boosters used to launch the Space Shuttle are retrieved for reuse after they travel back to Earth with the help of parachutes.

During World War II, Allied fighter pilots and bomber crews used para­chutes. Hundreds of combat fliers parachuted from planes, often after their planes had been hit by enemy fire. After the U. S. Doolittle Raid on Tokyo in 1942, all but one of the B-25 crews taking part had to use parachutes when their planes ran out of fuel over China.

In the 1940s, new parachute tech­niques were invented for jet pilots. The ejection seat, first tried in 1946, was available by 1951 with a pressure – operated parachute that would open at a preset, safe altitude. All a pilot had to do was jettison the cockpit cover and pull down a face blind; he and his seat were ejected from the airplane, and the para­chute opened. Ejection seats are now standard in most military airplanes.

propeller is a set of long blades attached to a hub in the center. The job of a propeller is to change the turning force, or torque, of an engine into thrust. Thrust is the force that moves an aircraft through the air.

Propellers and Engines

More than 100 years ago, the first air­planes were powered through the air by propellers. When the jet engine was invented, it looked like the propeller’s days might be over. Even in the age of jets and rockets, however, propellers are still widely used. A piston engine driv­ing a propeller is still the best way to power a small plane today.

There also are many turbine-powered planes with propellers. A turboprop engine runs a lot faster than the best speed for the propeller it controls, so the engine and propeller are connected by a gearbox. Just as a car’s gearbox lets its engine and wheels run at different speeds, a turboprop’s gearbox allows the engine to run at its ideal speed and the propeller to spin more slowly.