Satellites in orbit|
A satellite is an object orbiting the Earth, round and round, year in year out. It does not need refuelling because it moves all the time above the atmosphere. There is nothing to slow it down there.
Once a satellite is first launched, it orbits the Earth for years. Some of them fly at an altitude as high as 36000 kilometres out in space. Others fly much lower, only two to three hundred kilometres from the ground. Some move in a circuit round the Earth. Other satellite orbits may be like more or less flattened circles.
But how do we make the satellites move in a certain orbit round the Earth?
And what is it that keeps them in orbit once they have first been placed there?
The text of facts and the tasks of the teaching examples below will offer you a possibility of finding an answer to these and other questions.
|Satellite orbits |
|Satellites must move at a rather high speed in order to be able to fly round the Earth. Furthermore, strong forces are necessary in keeping satellites in orbit so that they do not disappear further out into space. We may produce something similar here on the ground.|
|Spacecraft work in orbits. Understanding this motion may at first seem rather intimidating. After all, to fully describe orbital motion we need some basic physics along with a healthy dose of calculus and geometry. However, as weíll see, spacecraft orbits arenít all that different from the paths of baseballs pitched across home plate. |
|There is, of course, no cannon launching the satellites into orbit, such as you have seen in some of the examples. That would in practice have been difficult.
The satellites are launched by rockets.
But what is it that makes the rocket speed up into the air? How does the rocket engine function?
|Learn about different exciting rocket techniques that you can test out for your self or take into the class-room and how to teach with rocketry, history and background information about rockets, payloads, how rockets work and basic introduction into rocket aerodynamics, what forces are generated and how to calculate them.|
|The space age was introduced 4th October 1957 by the Soviet Union launching of Sputnik 1. The news hit like a bombshell in large parts of the world. Here you may read about the space race between the former Soviet Union and the USA.
Do you know how many satellites there are orbiting round the world? Who owns these satellites and how useful do you think they are?
|A communications satellite is an artificial satellite stationed in space for the purposes of telecommunications. Modern communications satellites use a variety of orbits. In 1960, the simplest communications satellite ever conceived was launched. It was called Echo, because it consisted only of a large (100 feet in diameter) aluminized plastic balloon.|
|Military satellites are mainly used in the same way as the civilian satellites. Some of them are used to survey their own areas and those of other nations, among other things in order to warn against situations that may threaten peace. Others are used almost as civilian navigation satellites and communication satellites.|