Satellites

A geostationary orbit is one above the equator. It takes the satellite 24 hours to go round once. This means that satellite Y is always above town A. (Note that the satellite doesn't stay still. It does move but so does town A. They stay fixed relative to each other.)

• Used for communications eg phone and TV
• Because the satellite is in a fixed position relative to the Earth so dishes can always point in the same direction.
• GPS satellites are geostationary too.
• You SatNav constantly checks where it is in relation to these satellites.

Polar orbit goes over the poles and covers a lot of territory.

• Many countries visited so good for spying.
• Close to the ground so better photos (GoogleEarth)
• Weather photos