At what altitude from the earths surface would a spacecraft have to be at to establish a Geo stationary orbit?

Answer 1

At approximately 35,786 km (22,240 statute miles). A few 100 meters (or even a few kilometers) one way or the other will not matter, because the spacecraft will have to use fuel to maintain geostationary orbit in any case. This is because gravity is not uniform, due to the Sun, Moon, and other factors; also there is some drag forces from solar wind, etc.

Answer 2

It is certainly possible to put a satellite in lunar stationary orbit. It would need an altitude of about 87,000km. I'm not sure why a satellite over the far side would be useful. You are correct that it would be undetectable from Earth, but then Earth would also be undetectable from it. There is little benefit in really in putting a satellite up there compared to on the surface. What such satellites would be useful for is the same thing that geostationary satellites are useful for here: communications relay systems. A set of four lunar stationary satellites could be arranged so that all are in line of sight with the Earth, and they could give communications coverage to the entire lunar surface, allowing many applications to be set up on the far side.

Answer 3

circular geosynchronous orbit in the plane of the Earth's equator has a radius of approximately 42,164 km (from the center of the Earth). A satellite in such an orbit is at an altitude of approximately 35,786 kilometers above mean sea level. It will maintain the same position relative to the Earth's surface. If one could see a satellite in geostationary orbit, it would appear to hover at the same point in the sky, i.e., not exhibit diurnal motion, while one would see the Sun, Moon, and stars traverse the heavens behind it. This is sometimes called a Clarke orbit. Such orbits are useful for telecommunications satellites.

Every geosynchronous orbit has a semi-major axis of 42,164 km (26,200 miles).

A perfect stable geostationary orbit is an ideal that can only be approximated. In practice the satellite will drift out of this orbit (because of perturbations such as the solar wind, radiation pressure, variations in the Earth's gravitational field, and the gravitational effect of the Moon and Sun), and thrusters are used to maintain the orbit in a process known as station-keeping

Answer 4

At 22,236 miles:

http://www.gsfc.nasa.gov/gsfc/educ/fyeo/faq/gorbit.htm

Answer 5

22,300 miles from the surface, above the equator.

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Answer 6

Quantumc, a top contributor's answer was right, 22236 miles.
The other top contributors' answers were also right,

Answer 7

About 25.000 miles.

Answer 8

3000 miles.