Science & engineering
Ideal rocket delta-v
Relate mass ratio and specific impulse to ideal velocity change.
A clear answer. Here’s how.
Uses Δv=Isp·g₀·ln(m₀/mf), with standard gravity 9.80665 m/s² and final mass no greater than initial mass. Reports effective exhaust speed and propellant fraction. Assumes constant effective exhaust performance and a single ideal burn; gravity, drag, steering, finite-burn and staging losses are excluded.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Initial total mass (kg)
- 1000
- Final mass after propellant use (kg)
- 500
- Effective specific impulse (seconds)
- 300
Example result
- Ideal delta-v (m/s)
- 2,039.23553947
- Effective exhaust speed (m/s)
- 2,941.995
- Propellant mass fraction
- 0.5
- Mass ratio
- 2