Scientist proposes tiny satellites to sniff out nuclear weapons in space

Scientist proposes tiny satellites to sniff out nuclear weapons in space

A researcher at the Massachusetts Institute of Technology has proposed a new method to detect nuclear weapons hidden on satellites, offering a potential way to verify compliance with international law in an era of increasing geopolitical tension. The proposal, detailed in a feasibility study published in the journal Nature, describes a system of small "inspector" satellites capable of identifying the radioactive signatures of thermonuclear warheads.

The 1967 Outer Space Treaty, signed by 118 countries including the U.S., Russia, and China, bans the placement of nuclear weapons in space. However, the treaty lacks robust verification mechanisms. According to MIT Professor Areg Danagoulian, no verification methods had been proposed in unclassified, peer-reviewed literature until now.

The urgency for such a system increased following the 2022 launch of the Russian satellite Cosmos2553. While Russia claims the satellite is used for sensing and surveillance, U.S. Authorities believe it may carry components of a nuclear device undergoing testing. Danagoulian notes that Cosmos2553 was launched into a highly radioactive and hostile orbit, which he suggests is likely the best location for trapping electrons if a thermonuclear weapon were detonated.

The physics of detection

The proposed detection system relies on a process called proton-induced neutron spallation. This occurs when high-energy protons in the radioactive environment of low-Earth orbit—specifically the inner Van Allen radiation belt—collide with elements with high atomic numbers, such as plutonium and uranium.

Danagoulian explains that when an energetic proton slams into these materials, it can knock out approximately 40 neutrons. Because normal satellites do not emit neutrons at this volume, this creates a distinct signature.

To isolate this signal from the "noise" of space, the inspector satellite would utilize a specialized sensor system about the size of a large encyclopedia or a large shoebox. The design features:

• Neutron scintillators: Two panels of pixels that interact with radiation to emit light.
• Synthetic crystal diamond detectors: A "cage of diamond" sandwiching the panels to filter out protons and electrons, ensuring the system only records neutrons.
• Directional detection: The two-panel construction allows the sensor to determine if neutrons are coming from the suspected satellite.

Operational feasibility and impact

Danagoulian’s calculations suggest the system could detect a nuclear weapon with 99 percent accuracy if the inspector satellite orbits within 4,000 meters of the suspect craft for about a week. If the sensor can get within 1,000 meters, the detection time could be reduced to a single flyby lasting about one hour. Furthermore, a constellation of 10 such satellites could cut the detection process down to a matter of hours.

The risks of an orbital detonation are severe. In 1962, the U.S. Detonated a 1.4-megaton thermonuclear warhead in a test known as Starfish Prime. The blast destroyed one-third of the satellites in orbit at the time by injecting massive volumes of energized electrons into the inner Van Allen belt. Today, a similar event could destroy reconnaissance satellites, international communication platforms, and megaconstellations like Starlink and Amazon Leo.

Danagoulian warns that such a detonation would make low-Earth orbit and very low-Earth orbit uninhabitable for several years, disrupting GPS, telecommunications, and space-based internet. If a weapon were detected by his proposed system, the military could potentially jam the satellite's communications from the ground to prevent remote detonation, as there is currently no technology to safely defuse a nuclear weapon in space.

While Danagoulian clarifies that this is a feasibility study and not a "completely proven system," he hopes the work will lead to a proof-of-concept prototype. He is currently working with MIT’s Center for Nuclear Security and Policy to evaluate the policy implications. The research was supported in part by Longview Philanthropy, the Carnegie Foundation, and the National Nuclear Security Administration.