Description: Nuclear Thermal Propulsion (NTP) has been identified as a critical technology needed for human missions to Mars due to its increased specific impulse (Isp) as compared to traditional chemical propulsion systems. To achieve this high Isp, NTP reactors must operate at extremely high temperatures (i.e., >2400K) for long periods of time. However, many of the best materials for some reactor components (i.e., support rods, control drums, and the reflector) cannot operate at these high temperatures. Therefore, high temperature insulators that are chemically inert, neutronically acceptable, and structurally stable are desired. The Rover and Nuclear Engine for Rocket Vehicle Application (NERVA) program identified zirconium carbide (ZrC) as a leading candidate for NTP insulator materials. However, the inherent brittleness and high melting temperature of ZrC make fabrication of complex components such as long, hexagonal tie-tubes extremely difficult. Recently, advanced Vacuum Plasma Spray (VPS) forming techniques have been developed for producing near-net-shape components from Ultra High Temperature Ceramic (UHTC) materials such as tantalum carbide (TaC) and hafnium carbide (HfC). Building on this success, advanced VPS processing techniques will be developed for producing long, hexagonal ZrC based tie-tube support rods for NTP.

Benefits: NASA applications that would directly benefit from this technology include Nuclear Thermal Propulsion (NTP) and Nuclear Electric Propulsion (NEP). Initial NTP systems will have specific impulses roughly twice that of the best chemical systems, i.e., reduced propellant requirements and/or reduced trip time. The proposed Phase I and Phase II efforts would greatly assist NASA with achieving the promise of NTP and NEP. Potential NASA missions include rapid robotic exploration missions throughout the solar system and piloted missions to Mars and other destinations such as near earth asteroids.

Commercial sectors that will benefit from this technology include medical, power generation, electronics, defense, aerospace, chemicals, and corrosion protection. Specific applications include protective coatings, x-ray targets, valves, non-eroding throats and thrusters for propulsion, and crucible/furnace components.