Satellite orbit
From Wikipedia, the free encyclopedia
A satellite orbit is a path that a satellite makes around another object with sufficient mass to have a gravitational effect on the satellite. Satellites can be artificial manmade satellites or satellites may be naturally occurring such as moons, comets, asteroids, planets, stars, and even galaxies.
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[edit] Overview
Satellite orbits are always conic sections. That is to say they always form either circles, ellipses, parabolas, or hyperbolas. Since satellite orbits can be hyperbolic which are open-ended orbits, some comets or asteroids form an orbit where their path may come into our solar system and exit never to return. The first space missions to the moon were sent up in hyperbolic orbits so that if there were a system failure, the astronauts would not have been able to return.
Satellites follow specific orbits relating to the gravitational force between the satellite and the object it orbits. These orbits follow Newton’s laws of motion. However, in strong gravitational fields such as around neutron stars and black holes, Einstein's law of general relativity predicts orbits.
[edit] Natural satellites
All the objects including nebula, plasma, globular clusters and stars in the Milky Way Galaxy orbit their common center of mass, called the Galactic Center. Galaxies themselves orbit around a center of mass in galaxy clusters. Galaxy clusters orbit in superclusters.
Although, in atoms, electrons were once thought to orbit the nucleus, this has been shown not to be the case by quantum mechanics. However, the term "orbit" is still used for an electron although it is not an accurate description.
[edit] Manmade satellites
The first artificial satellite was placed in orbit by the Russians in 1957. That satellite, called Sputnik, signaled the beginning of an era.
Equatorial also polar satellites mostly fly at low altitudes between 100 and 1,000 miles.
Stationary satellites, on the other hand, are in very high equatorial orbits 22,300 miles above earth which exactly matches the earth's rotation speed so that the satellite can remain above one position on earth. To arrive at a geosynchronous orbit, the satellite is first launched to an orbit called geostationary transfer orbit, an elliptical orbit around the earth. After first-stage burnout, there follows a separation of the second stage, then the third stage fires to accelerate the spacecraft and places the satellite in a highly elliptical orbit 200 kilometers at its closest point to earth and 35,786 kilometers at its furthermost point. After scientists have checked the satellite systems, more burns put the satellite into its geosynchronous orbit.
For artificial satellites, NASA provides real-time tracking of the over 500 artificial satellites maintained in orbit about our earth. For the position of these satellites see NASA satellite tracking.
You can also download free satellite tracking software to display real-time positions of any satellite in orbit around the earth, such as Satscape
