Chapter 2 – Exploring Space Lesson 1 – The Science of Rockets Rocket technology originated in China hundreds of years ago and gradually spread to other parts of the world. Rockets were developed for military use as well as for fireworks A History of Rockets Rockets were very simple-arrow coated with a flammable powder that were lighted and shot with bows. The British greatly improved rocketry in the early 1800’s Origins of Rockets Modern rockets were first developed in the early 1900’s. Rocket design made major advance in World War II. Von Braun used his experience to direct the development of many rockets used in the US space programs. http://www.youtube.com/watch?v=2JJFQ 0kfanQ&feature=related Development of Modern Rockets Von Braun http://www.youtube.com/watch? v=WBi69V8oNuw&feature=related A rocket moves forward when gases shooting out the back of the rocket push it in the opposite direction. The movement of a rocket demonstrates a basic law of physics: For every force, or action, there is an equal and opposite force, or reaction How do Rockets Work? In order to lift off the ground a rocket must have more upward thrust than the downward force of gravity. Once a rocket is off the ground, it must reach a certain velocity in order to into orbit. The escape velocity a rocket needs to leave Earth is about 40,200 kilometers per hour. Orbital and Escape Velocity Three types of fuel are used to power modern spacecraft: Solid fuel, liquid fuel, and electrically charged particles of gas. Solid fuel and liquid fuel rockets carry oxygen that allows the fuel to burn. In a solid fuel rocket, oxygen is mixed with fuel, which is a dry explosive chemical. In a liquid fuel rocket, both oxygen and the fuel are in liquid form and stored in different components. Ion rockets do not burn chemical fuels, rather they expel gas ions out of their engines at very high speeds. Rocket Fuels A rocket can only carry so much fuel, before the chambers start to empty. The main advantage of a multistage rocket is that the total weight of the rocket is greatly reduced as the rocket rises. In a multistage rocket, smaller rockets, or stages, are placed one on top of the other and then fired in succession. In the 1960’s, the development of powerful multistage rockets such as the Saturn V made it possible to send spacecraft to the moon and the solar system beyond Multi-Stage Rockets http://www.youtube.com/watch?v=DDvlzdXDwA Multi-Stage Rockets Lesson 2 – The Space Program The space race began in 1957 when the Soviets launched the satellite Sputnik I into orbit. The United States responded by speeding up its own space program. The Race for Space A spacecraft orbiting Earth is an artificial satellite. The United States responded in early 1958 by launching its own satellite, Explorer I, into orbit. Later in 1958, the US established a government agency in charge of its own space program, called the National Aeronautics and Space Administration (NASA). The First Artificial Satellites The first American to orbit Earth was John Glenn, who was launched into space in 1962 aboard Friendship 7. The tiny capsule orbited Earth three times before returning to the surface. Humans in Space The American effort to land astronauts on the moon was named the Apollo program. Mission to the Moon . In July, 1969, three American astronauts circled the moon aboard Apollo II. . Neil Armstrong and Buzz Aldrin entered a tiny spacecraft called Eagle that later landed on the moon’s surface called the Sea of Tranquility. http://www.youtube.com/watch?v=zGNryrs T7OI The Moon Landings Over the next three years, five more Apollo missions landed on the moon. The minerals that make up moon rocks are the same minerals that are found on Earth. However, in some moon rocks these minerals combine to form kinds of rocks that are not found on Earth. One way the Apollo explored the moon’s surface was to crash equipment onto the moon’s surface. These instruments measured the moonquake waves that resulted. This allowed scientist to determine that the moon may have a small core of molten rock at the center. The Moon’s Surface Soon, humans may walk on the moon. In 2004, the U.S. announced a plan to establish a permanent colony of people on the moon. From such a base, missions could be launched to carry people to Mars New Missions to the Moon LESSON 3 – Exploring Space Today A space station provides a place where longterm observations and experiments can be carried out in space. In the 1970’s and 1980’s both the U.S. and the Soviet Union placed space stations in orbit. The International Space Station has large batteries to guarantee that it always has power. Its main source of power, though, is its eight large arrays of solar panels which converts sunlight into electricity. Space Station Information / data about other parts of the solar system have been collected by space probes. Each space probe has a power system to produce electricity, a communication system to send and receive signals, and scientific instruments to collect data and perform experiments. The scientific instruments that a probe contains depend on the probe’s mission. Some probes have small robots called rovers. Space Probes A rover has instruments that collect and analyze soil and rock samples. Probes have now visited or passed near all of the planets and have explored many moons, asteroids, and comets. Exploring with Space Probes Using Space Science on Earth Except for a few stray atoms, and molecules, most of space is empty. Since there is no air in space, there is no oxygen for astronauts to breathe. Because there is no air, there is nothing to hold the sun’s heat. Spacecraft must be well insulated to protect astronauts against the extreme temperatures outside. Vacuum Astronauts in orbit experience a feeling of weightlessness, or microgravity. Their mass is the same as it was on Earth, but on a scale their weight would register zero. Earth’s gravity is holding them in orbit. Long periods in microgravity can cause health problems. Microgravity The space program has developed thousands of products that affect many aspects of modern society, including consumer products, new materials, medical devices, and communication satellites. Space Spinoffs Space spinoffs include many devices that are used in consumer products, such as the joystick controller, bar codes on products you buy at a store, cordless power tools, scratch resistant lenses, freeze dried foods, smoke detectors, and shock-absorbing helmets. Consumer Products A variety of materials were first developed by chemists and engineers for use in spacecrafts. Examples: Flexible eyeglass frames, materials used in tennis rackets and golf clubs, shock absorbing materials in running shoes, ceramic materials used for braces, and insulating materials used in homes, cars, and trucks. New Materials Medical science has benefited greatly from the technology of the space program. Medical spinoffs include devices that use lasers to clean clogged arteries and pacemakers for hearts. Medical Devices Satellites are used for communications and for collecting weather data and other scientific data. Observation satellites are used for many purposes, including tracking weather systems, mapping Earth’s surface, and observing changes in Earth’s environment. Satellites are placed in different orbits depending on their purposes. Satellites