Transfer orbit

In orbital mechanics, a transfer orbit is an intermediate elliptical orbit that is used to move a spacecraft from one circular, or largely circular, orbit to another.

There are several types of transfer orbits, which vary in their energy efficiency and speed of transfer. These include:

• Hohmann transfer orbit, an elliptical orbit used to transfer a spacecraft between two circular orbits of different altitudes in the same plane
• Bi-elliptic transfer, a slower method of transfer, but one that may be more efficient than a Hohmann transfer orbit
• Geostationary transfer orbit or geosynchronous transfer orbit is usually also a Hohmann transfer orbit
• Lunar transfer orbit is an orbit that touches Low Earth orbit and a lunar orbit.