Overview
- A peer-reviewed feasibility study published July 8, 2026, by MIT physicist Areg Danagoulian models an 'inspector' satellite that would detect neutrons produced when high-energy protons in the Van Allen belts strike uranium or plutonium aboard a suspect spacecraft.
- The paper outlines a compact detector made of scintillator pixels, synthetic-diamond charged-particle filters, and neutron-scatter directional imaging to separate target neutrons from the heavy proton, electron, and atmospheric neutron background.
- Simulations show the system could identify a thermonuclear weapon with about 99 percent confidence if an inspector satellite shadows a suspect within roughly 4 kilometers for about a week, with detection time dropping to hours for closer approaches or multiple sensors.
- Major hurdles remain: the concept is untested in space, discriminating spallation neutrons from background is technically demanding, and effective use would require close-proximity maneuvers that raise collision, sovereignty, and diplomatic concerns.
- If developed and paired with international rules, the method could for the first time give states an objective way to verify the 1967 Outer Space Treaty and alter incentives for hidden orbital weapons, but it will need engineering, classified follow-up work at national labs, and political buy-in to become operational.