ROCKET SCIENCE AND SPACE EXPLORATION

INTRODUCTION

Nearly 800 years ago, the Chinese used gunpowder to propel projectiles into the air. This marked the beginning of rocketry. Gunpowder, being dry and usually packed tight into a tube, is a form of solid rocket fuel. For hundreds of years, solid-fueled rockets were used sporadically by many countries as weapons, but they never really gained popularity among military Generals or scientists. It wasn't until the beginning of the 20 ^th Century, when two men in two different countries independently began developing a new type of rocket fuel, that the skill of designing and making rockets became a science. Robert H. Goddard, an American physicist, and Konstantin Tsiolkovsky, a Russian schoolteacher, both believed that liquid-fueled rockets could attain higher altitudes and carry heavier payloads than solid-fueled rockets. While Tsiolkovsky worked primarily on paper, Goddard went beyond theory and the drafting table and actually built and tested the first liquid-fueled rocket. The work of these men helped create great interest in building rockets. In the first half of the 20 ^th Century, Goddard and Tsiolkovsky helped get rocket science off the ground. Their efforts inspired two other men who would take the science of rockets into space. Werner von Braun, a German physicist, and Sergei Pavlovich Korolev, a Soviet Union aeronautical engineer, headed programs in the later half of the 20 ^th Century that sent humans into space.

Once in space, a whole new realm of scientific exploration became possible.  Astronomy, physics, biology, geology, and many more sciences benefited from the new perspective of our planet, our solar system, and our universe that rockets provided.  Science grew more specialized and new professional fields began to open that would not have been possible in the first half of the 20 ^th Century.

The evolution of rockets from Goddard's almost skeletal liquid-fueled rockets (figure 1) to Werner von Braun's powerful Saturn V rocket that carried men to the moon expanded the role of science in our world.  This tutorial will discuss the history of rocketry and will briefly discuss how rocketry revolutionized the sciences.  The classroom exercises for this section (a link to those exercises follows this tutorial) call for students to perform their own research regarding professional fields in space sciences.  Therefore, this tutorial will provide only a few examples of space-related professional occupations.

ROCKET MEN

On March 16, 1926, Robert Goddard launched the world's first liquid-fueled rocket. The rocket only flew to an altitude of 152 feet, but it proved that liquid fuel worked. In 1929, Goddard was the first to successfully launch scientific payloads (a barometer and a camera) high into the air with a rocket. In 1932, he developed the gyro control apparatus that helped maintain stability and to guide a rocket's flight. Goddard's designs provided the foundation for modern rocketry. For this reason, he is often referred to as the Father of Modern Rocketry. But his work did not receive this kind of recognition while he was alive. It wasn't until 1959, 14 years after his death in 1945, that Congress posthumously awarded him a gold medal. Also in 1959, NASA's Goddard Space Flight Center was established in Greenbelt, Maryland. By then, two other giants in the field of rocket science had already claimed their place in history: Werner von Braun and Sergei Pavlovich Korolev.

Werner von Braun was born in Wirsitz, Germany on March 23, 1912. His interest with rockets got him into trouble as a youth. When he was 13 years of age, he strapped six skyrockets (a popular firework) to a red wagon and set them off. The wagon tore down his street a distance of five blocks and then the fireworks exploded. Young von Braun was caught by a policeman and was promptly punished by his father, who did not approve of his son's hobby. But his interest in rocketry was too great to be curbed. He earned his doctorate in physics at the age of 22 and in two years was heading Germany's rocket program. In World War II, von Braun led the development of the V-2 rocket, a ballistic missile that terrorized Great Britain. The V-2 rocket was responsible for the deaths of many civilians. Nazi Germany exploited von Braun's talents to wage war, but von Braun himself wanted to build rockets that would make it possible for humans to explore space and other worlds. At the close of World War II, von Braun and his fellow rocket scientists were supposed to be executed by German troops, but von Braun and his men safely made it to the American lines. They surrendered and were taken as prisoners of war.

Von Braun and his team of rocket scientists were not typical prisoners of war. They were scientists who had knowledge and experience the U.S. needed. By 1946, he and his team were in White Sands, New Mexico testing V-2 rockets. Later, von Braun moved to Huntsville, Alabama where he headed the U.S. Army rocket program. There, he developed the Redstone rocket, which launched the first U.S. satellite, Explorer 1, into orbit. The Redstone rocket also launched the first two Americans into space during the Mercury Program: Alan Shepard and Gus Grissom. Von Braun also guided the development of the Saturn V rocket, one of the most powerful and successful rockets ever built (figure 2). It was this rocket that helped achieve President Kennedy's goal of landing a man on the moon and returning him safely to the earth before the end of the decade. Before the successful launch of the first manned Saturn V in December of 1968, the U.S. was behind the Soviet Union in the space race. Von Braun's Soviet counterpart, Sergei Korolev, helped the Soviet Union take an early lead in the space race by becoming the first country to launch a satellite into orbit (Sputnik was launched on October 4, 1957), and the first to send a man into space (Yuri Gagarain on April 12, 1961).

Sergei Pavlovich Korolev (figure 3) was born on December 30, 1906 in the small Ukrainian city of Zhitomir. As a young man, he was first interested in aeronautical engineering. He designed gliders and planes before his interest evolved into rockets. But the pursuit of this interest was temporarily delayed when he was convicted of sabotage a crime he was not guilty of. Korolev spent almost six years in various Soviet prisons before being paroled in 1944. Once out of prison, he was sent to Germany to evaluate and restore captured V-2 missiles. Over time, he became the shadowy chief rocket designer in the Soviet Union. During his professional career, no one outside of the Soviet Union knew who he was. His accomplishments, however, were world famous. Korolev was not only a brilliant rocket scientist, but a crafty politician as well. Korolev's space spectacles delighted Soviet Premier Nikita Khrushchev. Korolev knew that if he kept ahead of the U.S. in space ventures, funding for his projects would continue.

In 1964, Premier Nikita Khrushchev was toppled from power and eventually replaced by Leonid Brezhnev. Brezhnev was not as fond on the Soviet Union's space program. He felt that is was too expensive and opted to funnel more funds into defense spending. This severely handicapped Korolev's efforts to win the race to the moon. All hopes of a Soviet manned lunar landing were ended on January 14, 1966 when Korolev died while undergoing a routine operation. By the end of 1968, the United States had taken the lead in the race to the moon with the success of Apollo 8, the first mission that put men into lunar orbit. This was a lead the United States would not lose. On July 20, 1969, Neil Armstrong took humankind's first steps on the lunar surface, and the race to the moon was over. Rocket science had finally taken human beings to another world (figure 4).

CAREERS RELATED TO SPACE EXPLORATION

Rocket science today is a diverse field that is made up of many specialized professions. Physicists, aeronautical engineers, chemists and several other disciplines all contribute to the overall design and production of modern rockets and spacecraft. Space science, too, has become more specialized as technology and the exploration of space expand. Astronomy, astrophysics, and planetary geology long time space-related professions have now been joined by professionals specializing in human physiology, plant biology, and microbiology. In the 21 ^st Century, professional careers in space are likely to continue to diversify as new discoveries and new technologies inspire new directions in the pursuit of knowledge about the universe we live in.

• Aeronautics - The art or science of flight; a science dealing with the operation of aircraft.

• Asteroids - Also known as the minor planets, are small bodies orbiting the Sun that resemble planets. More than 5,000 asteroids have been discovered, and most are found between Mars and Jupiter. Usually having an irregular shape, asteroids--at least those discovered thus far can range in size from 580 miles (940 km) in diameter, which is the size of the asteroid Ceres, to just 33 ft. (10 m) in diameter.

• Barometer - A instrument that measures air pressure.

• Black Hole - Is created by the total gravitational collapse of a massive star or group of stars. It is the final phase of some stars, in which gravity sucks the star in on itself. it implodes rather than explodes. This makes it so dense that not even light can escape its gravitational field.

• Brown Dwarfs - Are also called failed stars. They lack enough energy to be true stars but are also too massive and hot to be planets.

• Comets - Are made up of frozen dust and gases, and have been described as large, dirty snowballs with icy centers. They often travel on extremely elongated orbits around the Sun. Some comets have orbits that take just 10 years to circumnavigate while other comets have orbits that take hundreds of thousands of years to circulate. The tail of a comet, called a coma, forms when the comet comes within 100 million miles of the Sun. It is then affected by the solar wind (hydrogen and helium that travel away from the Sun at high speeds), which causes a tail of dust and gases to form behind the comet.

• Gyro A wheel or disk that rapidly spins.

• Meteors - Are fragments of comets, planets, moons, or asteroids. It is estimated that a billion meteors enter our atmosphere every day. Contact with our atmosphere causes most to disintegrate before reaching Earth. Those that do not disintegrate completely but fall to Earth are called meteorites.

• Milky Way - The galaxy containing our solar system.  It is about 100,000 light-years in diameter and about 10,000 light-years thick. Galaxies are immense systems containing billions of stars. Astronomers have estimated that the universe could contain 40 to 50 billion galaxies. Galaxies have different shapes: some are spiral, others are elliptical, or oval-shaped, and some are irregular.

• Nebula - A giant glowing cloud thought to be made up of dust and gas. Nebulae were thought to have been galaxies that appeared as a blur because they were so far away, but as more powerful telescopes were created, they showed that nebulae were not clumps of stars but in fact a hazy cloud of gasses. Bright stars nearby illuminate a nebula. More than 300 nebulae have been discovered and named.

• Neutron stars - Are formed after a supernova explodes and shrinks. The shrunken form of the star becomes incredibly dense and compact as gravity pulls all of its matter inward. It becomes so compressed that a million tons of its matter would hardly fill a thimble. This density crushes together the electrons and protons of atoms, turning them into neutrons.

• Orbit - Is the term for the path traveled by a body in space. It comes from the Latin orbis, which means circle. Some orbits are nearly circular, but the orbits of most planets are ellipses- shaped like ovals.

• Payload The load carried by a spacecraft that consists of things that relate directly to the purpose of the flight.

• Planet - Is the term used for a body in orbit around the Sun. The word comes from the Greek planetes, and means "wanderers." Our solar system has nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. An easy way to remember their names in the correct order is to keep in mind the following sentence: My Very Educated Mother Just Served Us Nine Pickles. The first letter of each word is the first letter of each planet. Since 1994, evidence has been found that planets also exist beyond our solar system. At least 10 planets existing in other solar systems have been discovered.

• Pulsars - Are believed to be rapidly spinning neutron stars that give off bursts of radio waves at regular intervals. Pulsar is a shortened version of Pulsating star.

• Quasars -  (quas[istell]ar objects) Are believed to be the most remote objects in the universe. Despite their small size they produce tremendous amounts of light and microwave radiation: not much bigger than Earth's solar system, they pour out 100 to 1,000 times as much light as an entire galaxy containing a hundred billion stars.

• Satellite - Is the term for a body in orbit around a planet, such as a moon. As long as our own moon was the only moon known, there was no need for a general term for the moons of planets. But when Galileo Galilei discovered the four main moons of the planet Jupiter, Johannes Kepler wrote Galileo a letter suggesting he call them "satellites" (from the Latin satelles, which means attendant). Today, the word satellite refers to not only moons, but to manmade objects that orbit a planet.

• Solar System - Is made up of the Sun ( solar means sun) at its center, the nine planets that orbit it, and the various satellites, asteroids, comets, and meteorites that are also controlled by the Sun's gravitational pull.

• Sun - Is the closest star to Earth and the center of our solar system. Every second, it converts 49 million tons (45 million metric tons) of matter into pure energy, which reaches us in the form of light. The Sun weighs more than 300,000 times as much as Earth and is 109 times larger.

• Sunspots - Appear as dark spots on the Sun, and are believed to be cooler than the rest of the Sun. They appear in 11-year cycles.

• S upernova - Is an extremely large exploding star. Just before the star dies, it releases huge amounts of energy, briefly becoming millions of times brighter than it was. Then it immediately shrinks.

• Stars - Are composed of intensely hot gasses, deriving their energy from nuclear reactions going on in their interiors. Our Sun is the nearest star. Stars are very large-- some are even bigger than planets. Our Sun has a diameter of 865,400 miles--making it a comparatively small star.

• White Dwarfs - Occur when a star runs out of energy and shuts down. The force of gravity at its center pulls the mass of the star in on itself, forcing it to collapse. It resembles the glowing cinders of a fire that has died down. It is called a white dwarf because it emits a white glow.

• National Space Society Web site : http://www.capstonestudio.com/mercury/

• The Space Center: Past, Present, and Future of Space Exploration
  http://www.flash.net/~imagine5/index.html

• NASA Kids
  http://kids.msfc.nasa.gov/

• National Air and Space Museum
  http://www.nasm.edu

• NASA Space Shuttle Launches
  http://www.nasa.gov/mission_pages/shuttle/main/index.html

• NASA Astronaut Biographies
  http://www.jsc.nasa.gov/Bios/

• Challenger Remembered: The Shuttle Challenger's Final Voyage
  http://www.seasky.org/sky5.html

• The Space Shuttle
  http://seds.lpl.arizona.edu/ssa/docs/Space.Shuttle/index.shtml

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• Title: Mars : The Nasa Mission Reports (Nasa Mission Reports)
  
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• Title: Voyage to Mars: NASA's Search for Life Beyond Earth

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• Title: Designs on Space : Blueprints for 21st Century Space Exploration

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• Title: The Scholastic Encyclopedia of Space

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• Title: MARS 2000: The Complete Guide to Robotic and Human Exploration of the Red Planet

  Author(s): World Spaceflight News
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