sci.specific-impulse Calculator
Calculates rocket specific impulse Isp = thrust/(mass flow × g₀) in seconds and converts to exhaust velocity v_e = Isp × g₀. Liquid hydrogen/oxygen (RL-10): Isp = 465 s; solid rockets: Isp ≈ 250 s; ion thrusters: Isp > 3,000 s — higher Isp enables more delta-v per unit fuel mass.
Inputs
- Thrust N
- Reference formula or conversion factor shown for context.
- Mass Flow Kg S
- Total mass (kg). Distinct from weight — weight = mass × gravity. Mass is constant; weight varies with location.
- Chamber Pressure Mpa
- Force per unit area (Pa). Atmospheric pressure at sea level: 101,325 Pa. Check whether gauge or absolute pressure is required.
- Exit Pressure Mpa
- Force per unit area (Pa). Atmospheric pressure at sea level: 101,325 Pa. Check whether gauge or absolute pressure is required.
Results
- specific impulse Isp (s)
- ISP (specific impulse) — rocket engine efficiency in seconds. Higher ISP means more thrust per kilogram of propellant consumed.
- effective exhaust velocity (m/s)
- Reference formula or conversion factor shown for context.
- thrust
- Forward propulsive force generated by the engine or motor. Net thrust = gross thrust minus inlet momentum drag.
- mass flow
- The computed mass of the object or substance.
- Isp = T / (ṁ × g₀)
- ISP (specific impulse) — rocket engine efficiency in seconds. Higher ISP means more thrust per kilogram of propellant consumed.
- Isp benchmarks
- Reference value for comparison — the industry standard, historical average, or target that this result is measured against.
impulse specific propellant exhaust thrust