Mission results
Custom celestial body editor
Stage-by-stage rocket planner
| Stage | Dry t | Fuel t | Payload t | Engines | Thrust kN | Isp vac | Isp SL | Copies | Actions |
|---|
Orbit and resonance calculator
Hohmann and interplanetary transfer planner
Maneuver and plane-change calculator
Landing and ascent planner
Antenna and relay range estimator
Fuel, engine, and burn-time planner
Mission route builder
Formula used
| Calculation | Formula | Purpose |
|---|---|---|
| Rocket delta-v | Δv = Isp × g₀ × ln(m₀ ÷ m₁) | Measures the velocity change available from fuel. |
| Thrust-to-weight ratio | TWR = thrust ÷ (mass × local gravity) | Checks liftoff, hover, and landing capability. |
| Orbital velocity | v = √[μ(2/r − 1/a)] | Calculates speed anywhere on an elliptical orbit. |
| Orbital period | T = 2π√(a³/μ) | Finds the time required for one orbit. |
| Escape velocity | vₑ = √(2μ/r) | Estimates the local speed needed to escape. |
| Plane change | Δv = 2v sin(Δi/2) | Estimates inclination-change cost at orbital speed. |
| Communications range | Range = √(combined antenna power × network power) | Estimates direct or relay link reach. |
How to use this calculator
- Select the calculator mode matching your mission task.
- Choose a celestial body and enter spacecraft values.
- Add rocket stages or mission segments when required.
- Apply a safety reserve for piloting and correction burns.
- Calculate, review warnings, and compare required delta-v.
- Copy results or export them as CSV or PDF.
Example mission data
| Example | Inputs | Expected planning use |
|---|---|---|
| Kerbin launcher | 14 t dry, 26 t fuel, 800 kN, 320 s Isp | Check launch TWR and low-orbit delta-v. |
| Kerbin orbit | 80 km periapsis, 120 km apoapsis | Find period, speeds, and circularization needs. |
| Mun lander | 8 t, 120 kN, 5 km descent | Estimate TWR, burn time, and suicide altitude. |
| Duna transfer | Kerbin to Duna, 80 km to 60 km | Estimate phase angle, transfer time, and capture. |
Frequently asked questions
What does delta-v represent?
Delta-v measures available velocity change. It combines engine efficiency and mass ratio. Higher mission budgets provide more flexibility.
Why calculate every rocket stage separately?
Each stage has different mass and engines. Separate calculations show where performance changes. They also reveal inefficient stage designs.
Which TWR is suitable for Kerbin launch?
A value above one can lift. Many players target roughly 1.2 to 1.7. Exact needs depend on vehicle design.
Does atmosphere change engine performance?
Yes, atmospheric pressure changes specific impulse. Vacuum engines usually perform poorly near sea level. Use pressure matching the current environment.
What is a transfer-window phase angle?
It is the target body’s angular lead. Correct timing reduces interplanetary transfer costs. The estimator assumes simplified circular coplanar orbits.
Can this calculate custom planet packs?
The interface includes custom configuration mode. Stock values remain the provided defaults. Modify the PHP body dataset for custom systems.
How much delta-v reserve should I keep?
Ten to twenty percent is common. New pilots may prefer larger reserves. Difficult landings also justify extra margin.
How accurate is the landing estimate?
It uses simplified vertical-motion equations. Terrain, steering, drag, and throttle reduce accuracy. Treat the result as a planning estimate.
Does aerobraking remove capture cost completely?
Not always, because geometry and heat matter. This tool applies a simplified reduction. Test risky entries with additional margin.
How are multiple antennas combined?
The estimator applies a configurable combining exponent. Different game settings may change effective power. Verify antenna rules for your installation.
Is this an official KSP tool?
No, it is an independent planner. Values are provided for educational gameplay assistance. Always verify unusual missions inside the game.