Did You Know?

Many weather and communications satellites need to remain above a particular point on the Earth. To do so, a satellite's speed must exactly match the Earth's rotation--it must orbit once every 24 hours. Such an orbit is called a geostationary or geosynchronous orbit. A geostationary orbit is about six times larger than a low Earth orbit (just above the atmosphere), where spacecraft typically circle the Earth every 90 minutes.

(Rev. 09/19/96)