Compare and contrast geostationary and low polar orbits.

Geostationary orbits are only possible at one distance from Earth. This is because the very nature of the geostationary orbit requires the satellite to have the same time period as the rotational period of the Earth. In contrast, a low polar orbit can exist at a number of different distances and tends to have an orbital period of twelve hours as opposed to twenty four. Geostationary satellites remain in the same place relative to Earth and low polar satellites move, covering every part of the Earth's surface in only a short time frame. This difference helps to separate the orbits into different applications; geostationary satellites are good for communication as the satellite does not need to be tracked and a constant signal can be maintained. In contrast, the low polar satellite is better for surveillance as it covers so much ground.