What is a Hohmann transfer orbit?

A Hohmann transfer is the most fuel-efficient two-impulse maneuver to transfer between two coplanar circular orbits. Process: 1) At starting orbit, perform prograde burn to raise apogee to target orbit altitude (enter elliptical transfer orbit); 2) At apogee (now at target altitude), perform second prograde burn to circularize into target orbit. Total delta-v is sum of both burns. The transfer orbit touches both the initial and final orbits (is tangent to both). Transfer time is half the period of the transfer ellipse. While most fuel-efficient, Hohmann transfers are slow for distant targets. Bi-elliptic transfers can be more efficient for very large radius changes (>11.94x). Used for GEO insertion, orbit raising, and rendezvous approaches.