Propulsive Efficiency of a Variable Specific Impulse Magnetoplasma Rocket Engine Calculator

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is a type of electric propulsion system for spacecraft.

The propulsive efficiency is a crucial parameter in evaluating the performance of a rocket engine, indicating how well it converts propellant energy into useful thrust. Practical rocket engines often have propulsive efficiencies less than 100% due to factors like incomplete combustion, heat losses, and other inefficiencies in the propulsion system.

The propulsive efficiency (η_p​) is defined by the following formula:

where,

• η_p​ is the propulsive efficiency,
• $T$ is the thrust produced by the rocket engine,
• V_e​ is the effective exhaust velocity of the rocket,
• ṁ_p is the mass flow rate of the propellants,
• I_sp​ is the specific impulse of the rocket engine,
• g₀ is the acceleration due to gravity (approximately 9.81 m/s²).