Category FLIGHT and M ОТІOIM

Some aircraft do not have ailerons or elevators because they do not have nor­mal wings and tail. Flying wing aircraft have no tail at all. These aircraft use a different type of control surface called an elevon, which is a tilting part at the back of the wing. Elevons combine the jobs of the ailerons and the elevators. If the elevons tilt up or down together, they work like elevators to raise or lower a plane’s nose. If they work in opposite
directions, one up and one down, they work like ailerons and make a plane roll.

Most airplanes have two small wing­like parts, one on each side of the tailfin. They are called tailplanes, or horizontal stabilizers. An elevator at the back of each stabilizer tilts up or down to con­trol pitch. Some planes have a different type of tailplane. The whole tailplane tilts instead of just the elevator. It does the job of the stabilizer and elevator together and is therefore sometimes called a stabilator. Other names for this part are all-moving tailplane or all­flying tailplane.

In some fighter planes, the pitch is controlled by small, tilting winglets on the nose known as canards.

Date of birth: May 26, 1951.

Place of birth: Los Angeles, California. Major contribution: First American woman to reach space.

Awards: Induction into National Women’s Hall of Fame and the Astronaut Hall of Fame; Jefferson Award for Public Service; Von Braun Award; Lindbergh Eagle; NCAA’s Theodore Roosevelt Award; NASA Space Flight Medal (twice).

fter graduating from high school in Los Angeles, California, Sally Ride went on to attend Stanford University in California. She graduated in 1973 with degrees in physics and English. Deciding to focus on astro­physics, Ride earned her master’s degree in 1975 and her doctorate in 1978, both from Stanford.

In January 1978, Ride was one of six women chosen by NASA for astronaut training. Her first chance to fly in space came in 1983. On June 18, she joined four other astronauts on STS-7 aboard the Space Shuttle Challenger. Ride’s main task was to work the Space Shuttle’s robot arm. This mission was the first to use the robot arm to deploy and to retrieve a satellite. STS-7 flew for six days before returning to Earth.

Ride’s second mission, STS 41-G, took off on October 5, 1984. Once again she flew in the Space Shuttle Challenger. This mission lasted eight days, and Ride worked the robot arm to deploy a satel­lite. The seven-member crew also carried

out experiments. This flight made Ride the first American woman to fly twice in space. Fellow astronaut Kathryn Sullivan became the first American woman to walk in space.

Ride was assigned a further Space Shuttle flight in 1985 and began prepar­ing for a launch the next year. That mis­sion was canceled when, in January 1986, Challenger exploded shortly after takeoff. The Challenger disaster caused NASA to ban further Space Shuttle flights until the cause of the explosion could be determined. Ride was chosen to sit on the commission that investigated the accident.

After that work was complete, she transferred to NASA headquarters in Washington, D. C., where she worked on long-range planning for the agency. Her Ride Report, issued in 1987, recommend­ed using the technology of space explo­ration to study conditions on Earth. This Mission to Planet Earth, as it was called, has been undertaken by NASA. Much of the research focused on the issue of cli­mate change. Another Ride recommen­dation was to begin planning for a mission to Mars. At the time, NASA did not pursue this plan, but instead focused its work on the International Space Station.

In 1987, Ride left NASA to accept a position at the Stanford University Center for International Security and Arms Control. Two years later, she joined the faculty of the University of California at San Diego, where she taught and carried out research in physics. For many years, Ride also directed the California Space Science Institute, although she left that post to focus on research, teaching, and her many other activities.

Over the next twenty years, Ride served on several government commit­tees involved with space and technolo­gy. When the Shuttle Columbia exploded in 2003, NASA launched a new investi­gation. As with the Challenger incident, Ride was a member of the commission studying that accident.

Ride also dedicated herself to pro­moting interest in science and space exploration among young people, espe­cially girls. She wrote several children’s books on space and took an active role in other efforts to build the popularity of space exploration. In 2001, she founded her own company, Sally Ride Science, to motivate girls and young women to pursue careers in science, math, and technology.

N

SEE ALSO:

• Astronaut • Challenger and

Columbia • NASA • Space Shuttle

_________________ J

shock wave in air is a sudden, huge rise in air pressure. Shock waves affect the flight of high­speed aircraft and spacecraft through the atmosphere.

Everyone who has heard thunder has experienced the effect of shock waves. A flash of lightning instantly heats the air to as much as 60,000°F (33,320°C). When air is heated, it expands. When it is heated to such a high temperature so quickly, air expands explosively and forms a shock wave. The shock wave rushes away from the lightning faster than the speed of sound. Within a few feet, it has slowed down and become an ordinary sound wave, which we hear as
thunder. Similarly, the sharp crack of a whip is produced when the tip of the whip goes faster than the speed of sound and sets off a shock wave.

Aircraft

When an aircraft flies through the air, it pushes the air in front of it out of its way, which causes disturbances in the air. Pressure waves travel away in all directions. The fastest they can move is the speed of sound. When the aircraft goes faster than the speed of sound, the pressure waves ahead of it cannot escape fast enough. They pile up togeth­er in front of the aircraft and produce a sudden jump in pressure-a shock wave. This shockwave spreads out from the aircraft’s nose in the same way that a wave forms in front of a ship’s bow. Another shock wave spreads out from the aircraft’s tail as air rushes into the hole left behind by the plane, like the wake that trails behind a ship. Other parts of a plane, such as the wings and

cockpit, produce more shock waves, but the nose and tail shock waves are the biggest.