New Nature Study Proposes Method to Detect Nuclear Weapons in Orbit

A study published in Nature Astronomy has proposed a novel technique to detect thermonuclear warheads in orbit, offering the first technical verification mechanism for the 1967 Outer Space Treaty, which prohibits nuclear weapons in orbit but has lacked a practical means of enforcement.

Led by Areg Danagoulian, a nuclear physicist and non-proliferation researcher at MIT, and partially funded by the U.S. National Nuclear Security Administration (NNSA), the study proposes using an inspection satellite equipped with a neutron detector to identify fissionable material in warheads by leveraging the natural radiation environment of Earth's inner Van Allen belt.

Current satellite technology cannot detect nuclear weapons in orbit, making the treaty's ban effectively unverifiable. In 2024, U.S. intelligence alleged that Russia's Kosmos-2553 satellite, positioned in a radiation-rich zone, was a testbed for developing a potential orbital nuclear anti-satellite weapon, but conclusive evidence remained elusive.

Danagoulian's simulation models a 9U CubeSat inspector satellite carrying a plastic neutron scintillator sandwiched between a single-crystal diamond detector. Positioned about 4 kilometers from a target satellite of Kosmos-2553's type, the inspector could confirm a thermonuclear signature within a week-long observation window. With a constellation of about 10 such satellites, the window shrinks to 15 hours, and to just one hour at a distance of 1 kilometer.

"The concept is most compelling as part of a cooperative treaty verification regime," said Thomas Gonzalez Roberts, an assistant professor at Georgia Tech who was not involved in the study. "If both parties agree to the inspection, these proximity operations are achievable and politically much more acceptable."

The technique has limitations. It is designed for satellites operating within the inner Van Allen belt and does not cover all orbital regimes. It also cannot distinguish between an offline nuclear reactor and a weapon — a gap the team says it is working to close.

Danagoulian hopes to collaborate with national laboratories to build a working prototype. "What I described in a paper is a feasibility study that shows that this is scientifically feasible, but it's still from an engineering point of view, a very difficult problem," he said.

New Nature Study Proposes Method to Detect Nuclear Weapons in Orbit

New Nature Study Proposes Method to Detect Nuclear Weapons in Orbit

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