 Hohmann transfer orbit

A Hohmann transfer uses two tangential impulses and one half of an elliptic Kepler orbit to move between two coplanar circular orbits.

A Hohmann transfer orbit is an elliptical orbit used to transfer a spacecraft between two circular orbits of different altitudes around a celestial body, typically a planet. This maneuver is named after the German engineer Walter Hohmann, who described it in 1925.