In orbital mechanics, the Hohmann transfer orbit is an orbital maneuver using two engine impulses which, under standard assumptions, move a spacecraft between two coplanar circular orbits. This maneuver was named after Walter Hohmann, the German scientist who published a description of it in 1925.In Soviet literature, such as Pionery Raketnoi Tekhniki, the term Hohmann-Vetchinkin transfer orbit is sometimes used, citing the presentation of the elliptical transfer concept by mathematician Vladimir Vetchinkin in public lectures on interplanetary travel given 1921-1925.