The specific impulse is a key performance parameter for rocket engines, measuring their efficiency in converting propellant mass into thrust. Ion thruster engines, also known as ion drives or ion propulsion systems, are a type of electric propulsion that uses ions for thrust generation. Specific impulse for ion thrusters is typically much higher than traditional chemical rockets.
Ion thrusters achieve high specific impulse by accelerating ions to high speeds using electric fields. The mass flow rate in this case is very low compared to traditional chemical rockets, leading to a more efficient use of propellant.
It is defined as the thrust generated per unit of propellant expended and is expressed in seconds.
where,
- is the specific impulse of the rocket engine (in seconds, s)
- F is the Thrust Produced
- ṁ is the mass flow rate of propellant in KG/Sec
- g0 is the acceleration due to gravity