4.4; Rockets

Keuzeopdracht bij hoofdstuk 4.4. Rakketten (Het werkstuk is in het engels, omdat dat beter uitkwam, aangezien de informatie ook engels was.) Rocket is a type of engine that can produce more power for its size than any other kind of engine. A rocket can produce about 3,000 times more power than an automobile engine of the same size. The word rocket is also used to mean a vehicle driven by a rocket engine. Rockets are made in a variety of sizes. Some rockets that shoot fireworks into the sky are only 2 feet (61 centimeters) long. Rockets of 50 to 100 feet (15 to 30 meters) long carry missiles that may be used to bomb distant targets during wartime. Larger and more powerful rockets lift artificial satellites into orbit around the earth. For example, the Saturn 5 rocket that carried astronauts to the moon stood about 363 feet (111 meters) high. The rockets now in use produce their power by burning a fuel. These rockets are called chemical rockets because burning is a chemical reaction. In addition, researchers have experimented with rockets that produce power by heating a propellant so that it expands. The heat can come from an electrical unit or a small nuclear reactor. A short history of the rocket
People use rockets chiefly for scientific research, space travel, and war. Rockets have been used in war for hundreds of years. In the 1200's, Chinese soldiers fired them against attacking armies. British troops used rockets to attack Fort McHenry in Maryland during the War of 1812 (1812-1815). After watching the battle, Francis Scott Key described "the rocket's red glare" in "The Star-Spangled Banner." During World War I (1914-1918), the French used rockets to shoot down enemy airplanes. Germany attacked London with rockets during World War II (1939-1945). In the Persian Gulf War (1991), the United States used Patriot missiles to intercept Iraq's Scud missiles. Scientists use rockets for exploration and research in the atmosphere and in space. Rockets carry scientific instruments high in the sky to gather information about the air that surrounds the earth. Since 1957, rockets have lifted hundreds of satellites into orbit around the earth. These satellites take pictures of the earth's weather and gather other information for scientific study. Rockets also carry instruments far into space to explore and study other planets. Rockets also power human space flights, which began in 1961. In 1969, rockets carried astronauts to the first landing on the moon. In 1981, rockets lifted the first space shuttle into orbit around the earth. The 3 stages of space rockets: The first stage, called the booster, launches the rocket. After the first stage has burned its propellant, the vehicle drops that section and uses the second stage. The rocket continues using one stage after another. Most space rockets have two or three stages

Atmospheric research: Scientists use rockets to explore the earth's atmosphere. Sounding rockets, also called meteorological rockets, carry such equipment as barometers, cameras, and thermometers high into the atmosphere. These instruments collect information about the atmosphere and send it by radio to receiving equipment on the earth. This method of collecting information and sending it great distances by radio is called telemetry Rockets also provide the power for experimental research airplanes. Engineers use these planes in the development of spacecraft. By studying the flights of such planes as the rocket-powered X-15, engineers learn how to control vehicles flying many times faster than the speed of sound. Launching probes and satellites. Rockets that carry research equipment on long voyages to explore the solar system are called probes. Lunar probes gather information about the moon. They may fly past the moon, orbit it, or land on its surface. Interplanetary probes take one-way journeys into the space among the planets. Interplanetary probes have explored Jupiter, Saturn, Uranus, and Neptune. Planetary probes collect information about the planets. A planetary probe travels in orbit around the sun with the planet it is exploring. Planetary probes have explored Mars and Venus. Rockets lift artificial satellites into orbit around the earth. Some orbiting satellites gather information for scientific research. Others relay telephone conversations and radio and television broadcasts across the oceans. The armed forces use satellites for communications and to guard against surprise missile attack. They also use satellites to observe enemy facilities and movements. Rockets that launch probes and satellites are called carrier rockets or launch vehicles. Most of these rockets have from two to four stages. The stages lift a satellite to its proper altitude and give it enough speed--about 18,000 miles (29,000 kilometers) per hour--to stay in orbit. An interplanetary probe's speed must reach about 25,000 miles (40,200 kilometers) per hour to escape earth's gravity and continue on its voyage. Space travel. Rockets provide the power for spacecraft that orbit the earth and travel to the moon and the planets. These rockets, like the ones used to launch probes and satellites, are called carrier rockets or launch vehicles. The first space launch vehicles were military rockets or sounding rockets that engineers changed slightly to carry spacecraft. For example, they added stages to some of these rockets to increase their velocity. Today, engineers sometimes attach smaller rockets to the first stage of a launch vehicle. These piggyback boosters provide additional thrust to launch heavier spacecraft. The Saturn 5 rocket, which carried astronauts to the moon, was the most powerful launch vehicle ever built by the United States. It is no longer in use. Before launch, it weighed more than 6 million pounds (2.7 million kilograms) and stood about 363 feet (111 meters) tall. It could send a spacecraft weighing more than 100,000 pounds (45,000 kilograms) to the moon. The Saturn 5 used 11 rocket engines to propel three stages. Reusable space shuttles, which are used to launch satellites, can fly into space and return to the earth for repeated journeys. In the future, space shuttles may carry people and supplies to and from space stations that will orbit the earth. Also, smaller rocket-powered vehicles called space tugs someday may provide transportation over short distances, such as from a shuttle vehicle to a space station or from one satellite to another. Such vehicles may also provide power for space probes launched to the planets from earth orbit.