Hohmann Transfer Orbit is an elliptical orbit that is used to transfer a spacecraft between two orbits of different altitudes around a central body. It is a maneuver that was invented by German scientist Wolfman Hohmann, in 1925. This orbit is considered the most fuel-efficient way of transferring a satellite or a spacecraft from one lower circular orbit to another higher circular orbit. 

When a satellite or a spacecraft is traveling from earth to any other destination such as the Moon or Mars, the spacecraft or the satellite moving directly from Point A to Point B consumes more fuel to escape from the earth’s gravitational pull and is more expensive to achieve. 

To reduce this menace, the spacecraft is first launched in a circular orbit from earth. Once it’s in orbit, the spacecraft accelerates itself by firing its rocket motors for a brief period to create a new elliptical orbit known as the ‘Hohmann Transfer Orbit’ where the satellite or the spacecraft steers away from the earth to reach the orbit at a higher altitude. Once it reaches the apogee (farthest point from the earth) of the Hohmann transfer orbit from the earth, the satellite or the spacecraft decelerates to then stabilize itself in the higher orbit from earth.

India’s Mars Orbiter Mission (MOM) used the Hohmann Transfer orbit to place the spacecraft in mars orbit. Instead of a direct exit from the earth, a slow exit with the Hohmann transfer orbit made the MOM more economical and a considerable amount of fuel was also conserved.