Hohmann Transfer Orbit

A Hohmann transfer orbit is an elliptical trajectory that connects two circular orbits using the minimum amount of delta-v (two-burn optimal transfer). The first burn at the starting orbit raises the apogee to the destination altitude, and a second burn at apogee circularises the orbit there. Proposed by Walter Hohmann in 1925, it remains the standard method for orbit raising and GTO-to-GEO circularisation. The trade-off is time — a Hohmann transfer is the slowest two-burn option. For more urgent transfers, bi-elliptic or continuous low-thrust spirals may be used.