KSP Orbital Velocity Guide
Kerbal Space Program rewards clean numbers. A small speed error can waste fuel. It can also place a craft into the ground, air, or deep space. This calculator gives quick orbital values for common stock bodies. It also supports custom body data for modded systems.
Why Orbital Speed Matters
Orbital velocity is the sideways speed needed to keep falling around a body. Higher altitude usually needs lower circular speed. Lower altitude usually needs higher speed. The body mass also matters. KSP expresses that strength through the gravitational parameter, often called mu. Larger mu means stronger gravity and faster required velocity.
Circular Orbit Planning
A circular orbit has one constant radius. The tool adds body radius and chosen altitude. It then uses the circular speed equation. This helps when setting parking orbits, station paths, satellite networks, and relay positions. It also gives escape speed, period, angular speed, and surface gravity for context.
Elliptical Orbit Planning
An elliptical orbit has a periapsis and apoapsis. The calculator uses the vis-viva equation for each end. Periapsis speed is faster. Apoapsis speed is slower. The semi-major axis controls the orbital period. The eccentricity shows how stretched the path is. Delta-v estimates help compare circularization needs at each end.
Using Presets And Custom Values
Preset values cover stock KSP bodies. Choose Kerbin, Mun, Minmus, Duna, Jool, and more. For planet packs, select custom. Enter radius and gravitational parameter. Keep units consistent. Altitudes should stay above the surface. Atmospheric worlds need extra clearance for stable low orbits.
Practical Mission Tips
Use this result before making a burn. Match the target velocity near the correct altitude. Burn prograde to raise apoapsis. Burn retrograde to lower it. At apoapsis, circularize with a prograde burn. At periapsis, lower apoapsis with a retrograde burn. Compare escape speed before interplanetary departures. Use the period value for rendezvous timing, relay spacing, and transfer windows.
Limits Of The Calculator
The values are ideal two-body estimates. They ignore drag, thrust losses, rotation, steering errors, and patched-conic transitions. Real flights need margin. Add fuel reserve for corrections. In atmosphere, use a higher orbit or account for drag. Check map view often. Save before experiments. Small margins protect long missions well and crews.