30-11-2012, 11:23 AM
Rockets and Satellites
Rockets and Satellites (power point) (1).pptx (Size: 3.23 MB / Downloads: 39)
Rockets
A rocket moves forward when gases expelled from the rear of the rocket push it in the opposite direction. Hot gases are propelled out of the back of a rocket engine. The force of the gas in one direction (action) produces an opposing force (reaction) that propels the rocket forward.
Space Shuttles
The Saturn V rockets that carried astronauts to the moon in the 1960’s and 1970’s were very expensive. In addition, they could not be reused because each stage burned up and fell back through earth’s atmosphere. In the late 1970’s, the National Aeronautics and Space Administration (NASA) developed the reusable space shuttles. They are called shuttles because they can go back and forth, or shuttle, between the earth and space. Since the first shuttle was launched in 1981, space shuttles have been the main way that the United States launches astronauts and equipment into space. NASA is studying several ideas for building better and less expensive ways of launching people and cargo into space. The ideal vehicle would be an aerospace plane that could take off from a runway, travel into space, and landing again on the runway.
Space Stations
A space station is a large satellite in which people can live for long periods. The first space station, the Soviet Union’s ‘Salyut’, was launched in 1971. In 1973, the United States launched Skylab, which carried a series of telescopes and medical, geological, and astronomical experiments.
Satellites
Satellites are used for communications, navigation, collecting weather data, and research, In addition, two-dozen Global Positioning Satellites give off signals that can be picked up by small receivers on earth. The receiver can then tell you where you are on earth’s surface.
The Different Satellites
Artificial Satellites- Artificial Satellites are used to relay telephone calls, to measure the earth’s atmosphere, and photograph weather systems, crops, troops, and ships.
Global Positioning Satellites- Global Positioning Satellites give off small signals that can be picked up by small receivers on earth. The receiver can then tell you where you are on the earth’s surface.
Geosynchronous Satellites- Geosynchronous Satellites are used to relay television signals and to map weather patterns.