page_title: Hohmann transfer orbit
hierarchical_section_title: Hohmann transfer orbit
caption_attribution_description: English: Animation of InSight's trajectory from 5 May 2018 to 26 November 2018&#160;&#160;&#160;&#160;&#160;&#160;InSight&#160;· &#160;&#160;&#160;&#160;&#160;&#160;Earth&#160;· &#160;&#160;&#160;&#160;&#160;&#160;Mars
context_page_description: In orbital mechanics, the Hohmann transfer orbit is an elliptical orbit used to transfer between two circular orbits of different radii around a central body in the same plane. The Hohmann transfer often uses the lowest possible amount of propellant in traveling between these orbits, but bi-elliptic transfers can beat it in some cases.
  The orbital maneuver to perform the Hohmann transfer uses two engine impulses, one to move a spacecraft onto the transfer orbit and a second to move off it. This maneuver was named after Walter Hohmann, the German scientist who published a description of it in his 1925 book Die Erreichbarkeit der Himmelskörper. Hohmann was influenced in part by the German science fiction author Kurd Lasswitz and his 1897 book Two Planets.
  The elliptic transfer orbits between different bodies are often referred to as Hohmann transfer orbits. When used for traveling between celestial bodies, a Hohmann transfer orbit requires that the starting and destination points be at particular locations in their orbits relative to each other. Space missions using a Hohmann transfer must wait for this required alignment to occur, which opens a so-called launch window.
context_section_description: In orbital mechanics, the Hohmann transfer orbit (/ˈhoʊmən/) is an elliptical orbit used to transfer between two circular orbits of different radii around a central body in the same plane. The Hohmann transfer often uses the lowest possible amount of propellant in traveling between these orbits, but bi-elliptic transfers can beat it in some cases.
  The orbital maneuver to perform the Hohmann transfer uses two engine impulses, one to move a spacecraft onto the transfer orbit and a second to move off it. This maneuver was named after Walter Hohmann, the German scientist who published a description of it in his 1925 book Die Erreichbarkeit der Himmelskörper (The Attainability of Celestial Bodies). Hohmann was influenced in part by the German science fiction author Kurd Lasswitz and his 1897 book Two Planets.
  The elliptic transfer orbits between different bodies (planets, moons etc.) are often referred to as Hohmann transfer orbits. When used for traveling between celestial bodies, a Hohmann transfer orbit requires that the starting and destination points be at particular locations in their orbits relative to each other.  Space missions using a Hohmann transfer must wait for this required alignment to occur, which opens a so-called launch window.  For a space mission between Earth and Mars, for example, these launch windows occur every 26 months.  A Hohmann transfer orbit also determines a fixed time required to travel between the starting and destination points; for an Earth-Mars journey this travel time is about 9 months. When transfer is performed between orbits close to celestial bodies with significant gravitation, much less delta-v is usually required, as Oberth effect may be employed for the burns.
  They are also often used for these situations, but low-energy transfers which take into account the thrust limitations of real engines, and take advantage of the gravity wells of both planets can be more fuel efficient.
caption: An example of the Hohmann transfer orbit
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