How the orbit calculator works
A circular orbit's speed and period depend only on its radius and the central body's gravitational parameter μ. A Hohmann transfer moves between two circular, coplanar orbits with two burns: one to enter an ellipse that touches both orbits, and one to circularize at the other end.
- Circular speed:
v = √(μ/r) - Period:
T = 2π·√(r³/μ) - First burn:
Δv₁ = √(μ/r₁)·(√(2r₂/(r₁+r₂)) − 1) - Second burn:
Δv₂ = √(μ/r₂)·(1 − √(2r₁/(r₁+r₂)))
Worked example: raising a LEO satellite
Raising a satellite from a 400 km to a 550 km circular orbit around Earth takes about 83 m/s in total, split almost evenly between the two burns, with a coast of about 47 minutes. Going from a 300 km parking orbit to geostationary altitude takes about 3.9 km/s.
Good to know
- This assumes impulsive burns and no plane change. Inclination changes cost far more.
- Pro adds ground-station geometry: maximum slant range, coverage radius and the longest pass at your minimum elevation, which you can feed straight into the link budget calculator.