Nuclear Electric Propulsion for Planetary Defense

As yet undetected near-Earth objects (NEO) may pose a threat to Earth, in varying degrees of magnitude. As such, the Planetary Defense Conference (PDC) hosts a hypothetical Impact Scenario yearly. The following design is in reference to the 2025 PDC Exercise [1]. Previous work has examined use of a solar electric propulsion (SEP) vehicle using ion beam deflection (IBD) to change the trajectory of a NEO prior to a possible Earth impact [2]. It is desired to determine if a similar spacecraft, relying on constant nuclear power is similarly capable of deflecting asteroids. The most affordable option for a near term nuclear electric propulsion (NEP) vehicle was assumed to be based upon reusing the planned 40 kWe Fission Surface Power system for the lunar surface. Combined with a tighter-beamed NASA Evolutionary Xenon Thruster (NEXT) gridded ion thruster, the system was assumed to be available as early as 2030. The system would be able to successfully divert a 4 Mt asteroid. Comparisons to other works show that an SEP solution (single or multiple spacecraft working in concert) would need roughly four times the power of the NEP vehicle to divert the same mass of asteroid.