Slipping Through Attackers' Fingers: Fast Neutron Communications for Space Cybersecurity

Multi-agent space systems are inherently promiscuous. Blasting radio signals to each other within a constellation or to a ground station, it is simple for adversaries to disrupt the confidentiality, integrity or availability of the communication. With increasing rendezvous proximity operations (RPO) capabilities, the communication security of multi-agent space systems - be they configured as co-orbital, in constellations or other topology, is vulnerable to attackers. Optical communications offer several security benefits compared to radiofrequency (RF) communications, but are fragile and easily disrupted given the precision required to point a laser into a small receptacle while satellites are flying at 11,300 kph. We propose engaging the nascent technique of communicating using fast neutrons for secure, out-of-band, multi-agent space communications. Fast neutrons offer unique physics-based security properties such as their the ability to penetrate materials and be difficult to intercept. Using attack trees, we conduct a comparative analysis across RF, optical and neutron communications to evaluate the difficulty to achieve an RPO-based eavesdropping mission. We demonstrate that fast neutron communications would be more secure than other multi-agent space communication modalities, should the technology be further developed and deployed on a spacecraft. Fast neutrons would literally slip through adversaries' fingers.