US researchers set common readiness criteria for space nuclear systems

(SpaceEnergy) US researchers have published unified technology-readiness criteria for space nuclear systems, including nuclear electric propulsion, reconciling differing NASA, Department of Defense and Department of Energy assessment frameworks.

The peer-reviewed framework defines requirements from Technology Readiness Level 1 through TRL 9, covering hardware fidelity, software maturity, system integration, environmental testing, lifetime considerations and validation against modelling and simulation.

The authors include researchers from NASA’s Marshall and Glenn research centres and Idaho National Laboratory, alongside industry specialists.

They said nuclear electric propulsion presents particular readiness-assessment challenges because the electric thruster and nuclear power subsystems can mature at different rates. Electric propulsion systems at 10 kWe and below have extensive operational heritage, while nuclear power systems in the 10-100 kWe range have received less sustained investment.

Readiness is lower for integrated electric propulsion and nuclear generation systems operating from 100 kWe into the multi-MWe range, according to the study.

The framework says qualification of a space nuclear system at TRL 8 would probably require hot nuclear testing, including operation at or near full power, to capture reactor-induced environmental effects. TRL 9 requires the system to have been proven through at least one successful operational mission.

The researchers recommend independent technical assessment at major advancement milestones, particularly where limited flight heritage makes readiness claims dependent on ground testing, validated analysis and demonstrated hardware performance.