Editing Hohmann transfer orbit (section)

===Type I and Type II===

An ideal Hohmann transfer orbit transfers between two circular orbits in the same plane and traverses exactly 180° around the primary.  In the real world, the destination orbit may not be circular, and may not be coplanar with the initial orbit.  Real world transfer orbits may traverse slightly more, or slightly less, than 180° around the primary.  An orbit which traverses less than 180° around the primary is called a "Type I" Hohmann transfer, while an orbit which traverses more than 180° is called a "Type II" Hohmann transfer.<ref name= "NASA-trajectories">NASA, ''Basics of Space Flight'', Section 1, Chapter 4, "[https://solarsystem.nasa.gov/basics/chapter4-1 Trajectories]". Retrieved 26 July 2017. Also available [https://spaceodyssey.dmns.org/media/57432/hohmann_transfer_orbits.pdf spaceodyssey.dmns.org] {{Webarchive|url=https://web.archive.org/web/20170728080707/https://spaceodyssey.dmns.org/media/57432/hohmann_transfer_orbits.pdf |date=2017-07-28 }}.</ref><ref>Tyson Sparks, [http://ccar.colorado.edu/asen5050/projects/projects_2015/Students/Alpert_Brian/interplanetary_transfer.html Trajectories to Mars] {{Webarchive|url=https://web.archive.org/web/20171028085842/http://ccar.colorado.edu/asen5050/projects/projects_2015/Students/Alpert_Brian/interplanetary_transfer.html |date=2017-10-28 }}, Colorado Center for Astrodynamics Research, 12/14/2012. Retrieved 25 July 2017.</ref>

Transfer orbits can go more than 360° around the primary. These multiple-revolution transfers are sometimes referred to as Type III and Type IV, where a Type III is a Type I plus 360°, and a Type IV is a Type II plus 360°.<ref>Langevin, Y. (2005). "Design issues for Space Science Missions," ''Payload and Mission Definition in Space Sciences'', V. Mártínez Pillet, A. Aparicio, and F. Sánchez, eds., Cambridge University Press, p. 30. {{ISBN|052185802X}}, 9780521858021</ref>