Equations · equation
Hohmann Transfer
Rocketry · 1925
- Equation
- Δv₁ = √(μ/r₁)·(√(2r₂/(r₁+r₂)) − 1)
- Field
- Rocketry
- Named After
- Walter Hohmann
- Year
- 1925
Symbols
Δv₁ the first burn (a second, at arrival, circularizes) · μ = GM of the central body · r₁ starting orbit radius · r₂ destination orbit radius · the transfer is a half-ellipse touching both
Significance
The cheapest way between two circular orbits: two burns joined by half an ellipse. Worked out by a German city architect as a hobby, decades before any rocket could try it; it still sets launch windows to Mars (every 26 months) and lifts satellites to geostationary orbit.
Open on the Equations shelf — the interactive card, the filters, and everything alongside it.