Artificial Satellites Around The Earth
For launch vehicles and artificial satellites, the orbital plane is a defining parameter of an orbit; as in general, it will take a very large amount of propellant to change the orbital plane of an object. Other parameters, such as the orbital period, the eccentricity of the orbit and the phase of the orbit are more easily changed by propulsion systems.
Orbital planes of satellites are perturbed by the non-spherical nature of the Earth's gravity. This causes the orbital plane of the satellite's orbit to slowly rotate around the Earth, depending on the angle the plane makes with the Earth's equator. For planes that are at a critical angle this can mean that the plane will track the Sun around the Earth, forming a Sun-synchronous orbit.
A launch vehicle's launch window is usually determined by the times when the target orbital plane intersects the launch site.
Read more about this topic: Orbital Plane (astronomy)
Famous quotes containing the words artificial, satellites and/or earth:
“Before I finally went into winter quarters in November, I used to resort to the north- east side of Walden, which the sun, reflected from the pitch pine woods and the stony shore, made the fireside of the pond; it is so much pleasanter and wholesomer to be warmed by the sun while you can be, than by an artificial fire. I thus warmed myself by the still glowing embers which the summer, like a departed hunter, had left.”
—Henry David Thoreau (1817–1862)
“To the Japanese, Portugal and Russia are neutral enemies, England and America are belligerent enemies, and Germany and her satellites are friendly enemies. They draw very fine distinctions.”
—Jerome Cady, U.S. screenwriter, and Lewis Milestone. Peter Voroshevski (Howard Clinton?)
“We have seen when the earth had to be prepared for the habitation of man, a veil, as it were, of intermediate being was spread between him and its darkness, in which were joined in a subdued measure, the stability and insensibilty of the earth, and the passion and perishing of mankind.”
—John Ruskin (1819–1900)