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There is only one geostationary orbit because in order for any mass m to orbit the Earth (ME) the gravitational force:
EQ1: Fg = GmME/r^2
has to be such that it is equal to the required centripetal force for uniform circular motion:
EQ2: Fc = mv^2/r
where v is the velocity of m at radius r (distance from the center of the Earth) and:
EQ3: v = 2(pi)(r)(f)
f is the frequency of rotation in revolutions per second. For geostationary orbit the satellite must be in a fixed position (it must have the same frequency of rotation or angular velocity as the Earth's rotation) relative to the Earth and orbit above the Earth's equator.
The necessary velocity to satisfy Fg = Fc is a specific value, therefore (since pi and f are fixed values) r is the only variable in EQ3. There is a specific orbital radius for geostationary orbit of any mass m.
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What is a geostationary satellite?
Geostationary is the moving orbit in the plane of the equator. Geostationary satellites are 22,300 miles above the Earths surface, and remain stationary at a fixed point. Weather and communication satellites are examples of geostationary satellites.
What does a satellite do when its in geostationary orbit?
it's hot. ;)
Why must the Earth-based satellite dish face a fixed direction if it remains in the same location with respect to a geostationary satellite?
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What are the main differences between geostationary orbit and polar orbit?
A polar orbit is an Orbit in which a Satellite passes above or nearly above both of the Geographical poles of the body (usually a planet such as the Earth, but possibly another body such as the Sun being orbited on each revolution. It therefore has an Inclination of (or very close to) 90 degrees to the Equator. Except in the special case of a polar Geosynchronous orbit, a satellite in a polar orbit will pass over the equator at a different Longitude on each of its orbits.A geostationary orbit (GEO) is a circular orbit directly above the Earth's Equator From the ground, a geostationary object appears motionless in the sky and is therefore the Orbit of most interest to operators of Communication Satellites. Their orbital periods (time taken to revolve around earth) is exactly the same as the planet's (such as Earth's) rotational period. The Geosynchronous orbit is approximately 36,000 km above Earth's surface.geostionary satellites are positioned at an exact height above the earth, at this height they orbit the earth at the same speed at which the earth rotates on its axis whereas polar satellites have a much lower orbit, orbiting the earth quite quickly, scanning different areas of the earth at fairly infrequent periods.
Why does a geosynchronous satellite not trace a path over the surface of Earth?
A geostationary orbit achieved by being in a location where the satellite's orbital period is 24 hours. This means the satellite is about 36,000 km (22,000 miles) above the Earth's surface. All orbits must therefore be over the equator. Every orbit around the earth looks like a circular (or elliptical) ring whose center (or one foci) is at the center of gravity of the Earth. An orbit exactly above the equator is one such orbit, but any orbit can be tilted as long as the center (or focus) stays at the Earth's center and the whole orbit is flat like a disk. On various NASA maps this makes the orbit look like a sinewave, but on a globe it stays a flat circle (or ellipse). On "Star Trek" I have seen errors a number of times on "Geostationary orbit over the North Pole", well you can't do that. Likewise, a "Lunar-stationary orbit" is impossible for a spacecraft, since Earth itself is already IN THE STATIONARY ORBIT POSITION! Remember that a geostationary orbit looks like it is always over the same spot on the Earth (or other body). If you were on the Moon, the Earth would be in the same position in the sky at all times.
