Engine specific impulse density (Isp) is a performance parameter used to characterize rocket engines and other propulsion systems. It measures the efficiency of an engine in converting propellant mass flow rate into thrust. Specifically, it represents the impulse produced per unit of propellant mass consumed.
Where:
- is the specific impulse density (s/kg),
- is the thrust produced by the engine (N),
- ˙ is the mass flow rate of propellant (kg/s), and
- is the standard acceleration due to gravity (9.81 m/s2).