KEO
Kerbisynchronous Equatorial Orbit (or KEO for short) is the Clarke Orbit of the planet Kerbin, and the most popular destination for satellite launches. [speculation] A spacecraft on this orbit will appear stationary when seen from the surface. This can be useful when establishing a wireless connection between the craft and a structure on the surface, but it also makes obesrvation of a certain spot on the surface easy. The orbital altitude is 2,868.75 km at an orbital speed of 1009.0 m/s, which is equivalent to a surfacespeed of zero.
Maneuver Planning
The basic maneuver plan for reaching this orbit is to first achieve a low energy orbit (LEO) and then perform two maneuvers to execute a Hohmann transfer. The first one called the periapsis maneuver is raising the apoapsis to the required altitude for a synchronous orbit. This places the spacecraft on a kerbisynchronous transfer orbit (KTO). The second one is at the apoapsis.
Depending on the required orbit the second burn also includes nearly all of the plane change to reduce the equatorial inclination to zero. For stationary orbits the periapsis maneuver should be executed when crossing the equatorial plane. Since the Kerbal Space Center is on the equator, the timing and trigonometry may be skipped.
The following are instantaneous impulse calculations for equatorial low energy orbits, and therefore the real maneuvers will always be somewhat more than these values.
| LEO Altitude | Periapsis | Apoapsis | Total |
|---|---|---|---|
| 70km | 676.6 m/s | 434.9 m/s | 1111.5 m/s |
| 90km | 659.6 m/s | 427.8 m/s | 1087.4 m/s |
| 100km | 651.5 m/s | 424.3 m/s | 1075.8 m/s |
| 120km | 635.5 m/s | 417.4 m/s | 1052.9 m/s |
| 150km | 612.7 m/s | 407.3 m/s | 1020.0 m/s |
| 200km | 577.4 m/s | 391.3 m/s | 968.7 m/s |
| 300km | 515.3 m/s | 361.3 m/s | 876.6 m/s |
For direct launches, transfers from the lowest orbits will be more efficient because they require less delta-v to reach from the surface of Kerbin. Higher LEOs may be preferable if the spacecraft is visiting a tug or space station and requires altitude above the atmosphere to execute a rendezvous. These maneuver plans may also be useful for one who wishes to boost a large space station assembled on LEO to KEO.
Other celestial bodies
In theory those orbits also exists for other celestial bodies, but may be outside the sphere of influence.
See also
- Geostationary orbit on Wikipedia
- Geosynchronous orbit on Wikipedia
- Synchronous orbit on Wikipedia
