It depends entirely upon the speed of the satellite and the altitude of the satellite above earth's surface. Once you figure in distance and speed, duration should be relativley easy to figure out. Satellites orbiting earth must travel at atleast 8 kilometers per second, which comes to about 5 miles per second, in order to stay in orbit. A satellite must also orbit no lower than 150 kilometers above the earth's surface, which comes to about 93 miles, in order to avoid friction from earth's atmosphere. So satellites generally travel pretty fast. However, depending on the distance (as a result of the altitude) and speed, a full orbit of a satellite might be as short as a couple minutes, or as long as a couple hours.

The closer an object is to the Earth, the faster it must circle to balance the gravitational pull of the Earth. The closest satellites (~100+ km) are in in low Earth orbit (LEO); these can circle the Earth in as little as 90-100 minutes. Any lower than this and the atmosphere would quickly slow the object down so that it would fall back to Earth after relatively few orbits. Many of our communication satellites are so much higher (~36,000 km) that they require exactly one day to circle the planet. Objects at this distance above the equator are always in the same place in the sky which is why so many satellite dish antennas can point at one spot and never move. This orbit is sometimes called "geosynchronous" and objects in this orbit are called "geostationary." The moon is our best known satellite. It is about 384,000 km from Earth on average and takes about 28 days to complete one orbit. There are other satellites at other altitudes with other periods. Some (like the moon) have elliptical orbits which bring them closer for a little while then farther away for the rest of the orbit. The most curious thing we have sent up may be a solar observatory which travels with the Earth around the sun at a point where the gravitational pull of the sun equals the pull of the Earth, so it just travels with us between us and the sun - not technically a satellite of Earth, but curious nonetheless.

If it is in a stable orbit it simply depends on how "high" it is (how far out). at each distance it requires a specific speed to maintain a stable orbit.

Kepler's third law: "The squares of the orbital periods of planets are directly proportional to the cubes of the semi-major axis of the orbits." The semi major axis is the distance from the center of gravity of the earth to the center of the satellite at its highest point. The formula is: period = 2 pi sqrt(a^3 / (G (M + m))) If M the mass of the Earth is much bigger than m, the mass of the satellite, you can pretend m is zero. Google can do the rest. Say you want your satellite to be 100 miles high ... Type this into google: 2 * pi * sqrt((radius of the earth+ 100 miles)^3 / (G * (mass of the earth))) http://www.google.com/search?hl=en&q=2+*+pi+*sqrt%28%28radius+of+the+earth%2B+100+miles%29%5E3++%2F+%28G+*+%28mass+of+the+earth%29%29%29

satellites actually rotate together, takeing aproximently 23 hour 56 min....located 22,236 miles or(36,000) km from the equator...geosyncronis orbit...or the clarke belt, named after auther clarke..writer,who preposed the idea to have satellites in orbit with earth to maintain possition...or leo satellites located between 85km to 500 km...these are goverment owned sats( low earth orbit) satellites...

I don't care when it was that's bs, just admit ur wrong, no satelite can orbit below 172 miles from the surface..if wiki was omnicient it wouldn't be free for no one would spend millions at harvard and Mit- h nevermind I went there for free