## Why have different types of orbit?Unless a satellite is always in the same place from your point of view, it would be impossible to point a satellite dish in the right direction and receive a continuous signal. Without the 'geosynchronous' satellites, we could never have satellite television!
In 24 hours they travel the complete circumference of their orbit =
So geostationary satellites travel over 250 million metres per day just to keep up with the Earth. To do this their speed must be: So their speed = 3,080 m/s or 3.1 km/s Compare this with the speed you are travelling due to the spin of the Earth.
Polar satellites are only about 700 km above the Earth. This gives them a total orbit radius of 7,000 km approx. Their circumference of orbit is If they travel at 7.5 km/s, time taken = distance / speed = 44,000 / 7.5 So the time taken for one orbit = 5,900 seconds = 97 minutes. |