With the capability of generating high thrust and 100% more specific impulse than the best chemical rockets, the time and cost-saving potential of nuclear thermal rockets (NTR) for deep-space missions is once again gaining interest at NASA.
Although never flown, the NTR concept is relatively simple. The rocket engine is based around a nuclear fission reactor, which heats the liquid hydrogen (LH2) propellant instead of igniting combustible fuel.The idea goes back to the earliest days of the nuclear age, and has been studied at various levels for more than five decades, but the potential merits of such a high-thrust propulsion system have recently become more appealing to NASA as it develops an evolvable architecture for exploring Mars and beyond.
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