Editing Hohmann transfer orbit (section)

== Example ==
[[File:Total energy during Hohmann transfer.png|thumb|upright=1.2|Total energy balance during a Hohmann transfer between two circular orbits with first radius <math>r_p</math> and second radius <math>r_a</math>]]
Consider a [[geostationary transfer orbit]], beginning at ''r''<sub>1</sub> = 6,678&nbsp;km (altitude 300&nbsp;km) and ending in a [[geostationary orbit]] with ''r''<sub>2</sub> = 42,164&nbsp;km (altitude 35,786&nbsp;km).

In the smaller circular orbit the speed is 7.73&nbsp;km/s; in the larger one, 3.07&nbsp;km/s. In the elliptical orbit in between the speed varies from 10.15&nbsp;km/s at the perigee to 1.61&nbsp;km/s at the apogee.

Therefore the Δv for the first burn is 10.15&nbsp;−&nbsp;7.73 = 2.42&nbsp;km/s, for the second burn 3.07&nbsp;−&nbsp;1.61 = 1.46&nbsp;km/s, and for both together 3.88&nbsp;km/s.

This is ''greater'' than the Δv required for an [[escape orbit]]: 10.93&nbsp;−&nbsp;7.73 = 3.20&nbsp;km/s. Applying a Δv at the [[Low Earth orbit]] (LEO) of only 0.78&nbsp;km/s more (3.20−2.42) would give the rocket the [[escape speed|escape velocity]], which is less than the Δv of 1.46&nbsp;km/s required to circularize the geosynchronous orbit.  This illustrates the [[Oberth effect]] that at large speeds the same Δv provides more [[specific orbital energy]], and energy increase is maximized if one spends the Δv as quickly as possible, rather than spending some, being decelerated by gravity, and then spending some more to overcome the deceleration (of course, the objective of a Hohmann transfer orbit is different).