Orbit types of satelites (2)

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Synchronous Classifications Synchronous Orbit - An orbit where the satellite has an orbital period equal to the average rotational period (earth's is: 23 hours, 56 minutes, 4.091 seconds) of the body being orbited and in the same direction of rotation as that body. To a ground observer such a satellite would trace an analemma (figure 8) in the sky. Semi-Synchronous Orbit (SSO) - An orbit with an altitude of approximately 20,200 km (12544.2 miles) and an orbital period of approximately 12 hours Geosynchronous Orbit (GEO) - Orbits with an altitude of approximately 35,786 km (22,240 miles). Such a satellite would trace an analemma (figure 8) in the sky. Geostationary orbit (GSO): A geosynchronous orbit with an inclination of zero. To an observer on the ground this satellite would appear as a fixed point in the sky. Clarke Orbit - Another name for a geostationary orbit. Named after the writer Arthur C. Clarke. Supersynchronous orbit - A disposal / storage orbit above GSO/GEO. Satellites will drift west. Also a synonym for Disposal Orbit. Subsynchronous orbit - A drift orbit close to but below GSO/GEO. Satellites will drift east. Graveyard Orbit - An orbit a few hundred kilometers above geosynchronous that satellites are moved into at the end of their operation. Disposal Orbit - A synonym for graveyard orbit. Junk Orbit - A synonym for graveyard orbit. Areosynchronous Orbit - A synchronous orbit around the planet Mars with an orbital period equal in length to Mars' sidereal day, 24.6229 hours. Areostationary Orbit (ASO) - A circular areosynchronous orbit on the equatorial plane and about 17,000 km(10557 miles) above the surface. To an observer on the ground this satellite would appear as a fixed point in the sky. Heliosynchronous Orbit - An heliocentric orbit about the Sun where the satellite's orbital period matches the Sun's period of rotation. These orbits occur at a radius of 24.360 Gm (0.1628 AU) around the Sun, a little less than half of the orbital radius of Mercury. Special Classifications Sun-synchronous Orbit - An orbit which combines altitude and inclination in such a way that the satellite passes over any given point of the planets's surface at the same local solar time. Such an orbit can place a satellite in constant sunlight and is useful for imaging, spy, and weather satellites. Moon Orbit - The orbital characteristics of earth's moon. Average altitude of 384,403 kilometres (238,857 mi), elliptical-inclined orbit. Pseudo-Orbit Classifications Horseshoe Orbit - An orbit that appears to a ground observer to be orbiting a certain planet but is actually in co-orbit with the planet. See asteroids 3753 (Cruithne) and 2002 AA29. Exo-orbit - A maneuver where a spacecraft approaches the height of orbit but lacks the velocity to sustain it. Orbital Spaceflight - A synonym for Exo-orbit. Lunar transfer orbit (LTO) - Prograde Orbit - An orbit with an inclination of less than 90°. Or rather, an orbit that is in the same direction as the rotation of the primary. Retrograde orbit - An orbit with an inclination of more than 90°. Or rather, an orbit counter to the direction of rotation of the planet. Almost no satellites are launched into retrograde orbit because the quantity of fuel required to launch them is much greater than for a prograde orbit. This is because when the rocket starts out on the ground, it already has an eastward component of velocity equal to the rotational velocity of the planet at its launch latitude.