Synchronous orbit

From Kerbal Space Program Wiki
Revision as of 14:04, 30 August 2013 by Toa Aerrow (talk | contribs) (-added table showing altitudes of geostationary and semi-stationary orbits; -added link to forum thread with formula for calculating (semi)synchronous orbits)
Jump to: navigation, search

A stationary orbit is an orbit with the same orbital period as the rotational period of the orbited body. The eccentricity is equal to 0 and the inclination is exactly 0°. A satellite on this orbit will stay in the sky at the same position at all times, the surface velocity is zero and making the communication easy as the ground based telescopes don't have to follow the satellite's relative motion.

A stationary orbit is a special kind of synchronous orbit, which all have the same orbital period but may differ in inclination or eccentricity. Satellites on a synchronous but not stationary orbit have a ground track forming an analemma. Because it is impossible to get all values exact for a stationary orbit, every satellite on a synchronous orbit form an analemma.

Some celestial bodies don't allow synchronous orbits, and thus also no stationary orbits, because the altitude lies outside the celestial bodies' sphere of influence. This is because of a very slow rotation requiring a very high altitude to allow such long orbital periods explaining why all tidally locked moons don't have a synchronous orbits. Moho is the only planet without any synchronous orbit, because it's very slow rotational period with only almost two rotations in one orbit.

Stationary Orbits

[*] indicates that the altitude resides outside the SOI

[#] indicates that the altitude is the same as the orbit of another object

Geostationary Orbit Semi-Stationary Orbit
Moho 30,993.821km [*] 19,656.592km
Eve 10,958.472km 6,877.502km
Gilly 42.138km 21.734km
Kerbin 2,868.75km 1,585.176km
Mun 2,970.563km [*] 1,797.329km
Minmus 357.94km 203.286km
Duna 2,879.999km [#] 1,695.873km
Ike 1,133.895km [*] 666.204km
Dres 732.244km 410.219km
Jool 15,010.46km 7,235.761km
Laythe 4,686.318km [*] 2,767.176km
Vall 3,593.201km [*] 2,152.563km
Tylo 14,157.877km [*] 8,696.88km
Bop 2,618.169km [*] 1,606.391km [*]
Pol 2,415.079km 1,505.122km
Eeloo 683.69km 352.989km

See also