Synopsis
The report discusses the potential use of nuclear thermal propulsion (NTP) and nuclear electric propulsion (NEP) systems to enable human exploration missions to Mars. It focuses on an “opposition-class” crewed Mars mission with a 2039 launch date, preceded by cargo flights beginning in 2033.
NTP System
- Uses a nuclear reactor to directly heat hydrogen propellant and expel it through a nozzle to generate thrust. Could achieve 900+ seconds of specific impulse (Isp) and 100,000+ lbf of thrust.
- Prior NTP development (NERVA program) demonstrated feasibility but did not fully address flight system requirements. No integrated flight system has been tested or flown.
- Main challenges now are achieving high enough fuel temperatures (goal 2700K) for required Isp, storing hydrogen propellant with minimal losses, lack of test facilities, and rapid start-up capability.
NEP System
- Uses a nuclear reactor to generate electricity that powers electric thrusters to accelerate propellant (e.g. xenon). Lower thrust but 2,000+ seconds Isp.
- Would still require a supplemental chemical propulsion system for high thrust maneuvers.
- Main challenges are scaling up to megawatt power levels and developing integrated system. No MW-class integrated system has been tested.
For both NTP and NEP, key questions remain around optimal fuel types and enrichment levels. Studies needed to evaluate HEU and HALEU options.
Aggressive development programs outlined but even with substantial investments, still uncertainty if NTP and especially NEP could meet 2039 target date. Multiple cargo flights using these systems would reduce risks for eventual human missions.
Beyond Mars missions, NTP and NEP systems could enable ambitious science missions and support national security space objectives. Terrestrial nuclear power synergies also possible.
