The specific impulse is a key performance parameter for rocket engines, measuring their efficiency in converting propellant mass into thrust. Nuclear thermal rocket engines use nuclear reactions to heat a propellant, typically hydrogen, to high temperatures and expel it through a rocket nozzle to generate thrust.
For nuclear thermal rockets, the primary source of thrust is the high-velocity expulsion of the heated propellant. The heating is achieved through a nuclear reactor, and the propellant is typically hydrogen due to its favorable properties for high-temperature applications.
Nuclear thermal rockets have the potential for high specific impulse values compared to traditional chemical rockets, making them attractive for deep-space exploration where efficiency is crucial.
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