SPRINTR

SPRINTR (Scored Plate Reactor for an Innovative Nuclear Thermal Rocket) is a nuclear thermal propulsion engine developed by Howe Industries under NASA SBIR funding. The system uses a compact fission reactor with a novel scored-plate fuel element geometry to heat liquid hydrogen propellant to high temperatures before exhausting it through a nozzle, achieving specific impulse roughly double that of the best chemical rockets.

The scored plate design allows for efficient heat transfer from fuel elements to the hydrogen propellant stream while maintaining structural integrity at the extreme temperatures required for high-performance nuclear thermal operation. The reactor operates at 40 MW thermal power, producing 9,930 N of thrust at 843 seconds specific impulse with a core mass of 2,730 kg.

Nuclear thermal propulsion offers a compelling intermediate option between chemical rockets (300-450 s Isp) and electric propulsion (1,000-10,000 s Isp, very low thrust): it provides thrust levels compatible with fast human-rated missions to the Moon and Mars while cutting propellant mass requirements roughly in half compared to chemical alternatives. SPRINTR is designed to be a relatively compact NTR engine suitable for upper stage or in-space propulsion applications.