Verifying the Outer Space Treaty: Detecting Nuclear Weapons in Orbit

• The 1967 Outer Space Treaty bans nuclear weapons in space, but currently lacks a practical verification mechanism to confirm if nations are complying.
• MIT Professor Areg Danagoulian has proposed a method to detect fissile material in orbit by measuring neutrons induced by high-energy protons in the Van Allen radiation belts.
• A detection system mounted on a 9U CubeSat could confirm the presence of nuclear material within one week from 4 km away, or within one hour at 1,000 m.

The Problem with Verification

• The Outer Space Treaty prohibits weapons of mass destruction in space, yet there is no way to verify whether satellite launches contain such devices.
• Recent concerns have centered on Russia's 2022 launch of the Cosmos 2553 satellite, which was placed in a high-radiation, unusual orbit suitable for testing nuclear-armed anti-satellite (ASAT) components.
• Experts fear that detonating a nuclear weapon in low Earth orbit (LEO) would create an artificial radiation belt, catastrophically destroying critical infrastructure including communication, scientific, and GPS satellites.

Proposed Technical Solution

• The proposed detection method relies on the "spallation" effect: when high-energy protons from the Van Allen belts strike uranium or plutonium, they trigger the emission of numerous neutrons.
• The inspector satellite would feature a two-panel array of neutron-sensitive scintillators sandwiched between diamond veto detectors to filter out noise and identify the direction of the neutron source.
• Danagoulian emphasizes that while the concept is scientifically feasible and relies on fundamental physics rather than potentially deceptive intelligence, it remains a theoretical model requiring further engineering development to be practical.