MIT researcher proposes sensor system to detect nuclear weapons in space

MIT researcher proposes sensor system to detect nuclear weapons in space

A Massachusetts Institute of Technology physicist has developed a theoretical method to determine if satellites orbiting Earth are secretly carrying nuclear weapons, addressing a long-standing verification gap in international space law.

The proposal, authored by Associate Professor Areg Danagoulian and published in the journal Nature, describes a satellite-based sensor system capable of detecting radioactive materials by utilizing the natural radiation environment of Earth. The research comes amid heightened geopolitical tensions and U.S. Warnings regarding Russian space activity.

The Verification Gap

The 1967 Outer Space Treaty, signed by 118 countries including the U.S., China, and Russia, bans the placement of nuclear weapons in space. However, the treaty has lacked robust means of verification, according to Danagoulian. Until now, no verification methods had been proposed in unclassified, peer-reviewed literature.

The urgency for such a system increased following the 2022 launch of the Russian satellite Cosmos2553. While Russia claims the craft is used for surveillance and sensing, U.S. Authorities believe it may carry components of a nuclear device undergoing testing, potentially as a precursor to an anti-satellite nuclear weapon.

Danagoulian noted that Cosmos2553 was launched into a highly radioactive orbit that most spacecraft avoid. That location is likely the best point for trapping electrons if you were to detonate a thermonuclear weapon, he explained.

The Physics of Detection

The proposed system relies on a process called spallation. Earth is surrounded by the Van Allen radiation belts, which trap high-energy protons. When these protons collide with elements with a high atomic number, such as plutonium or uranium, they knock loose a large number of neutrons.

According to Danagoulian, a single proton slamming into these materials may knock out about 40 neutrons. He estimates a thermonuclear weapon could emit as many as 40 million neutrons per second when encountering protons in the Van Allen belt. Because ordinary satellite materials like plastic and aluminum do not produce similar signals, these neutrons serve as a telltale sign of a nuclear weapon.

To filter out "noise" from the harsh space environment, Danagoulian proposes an "inspector" satellite equipped with a sensor roughly the size of a large encyclopedia. The system would use:

• Scintillators: Two panels of neutron sensor pixels that emit light when interacting with radiation.
• Synthetic Crystal Diamond Detectors: These sandwich the panels to distinguish neutrons from natural protons and electrons.
• Directional Detection: By orbiting below the suspect satellite, the sensor can differentiate between neutrons coming from the target above and "albedo neutrons" reflecting from Earth below.

Feasibility and Accuracy

Danagoulian’s feasibility study calculates that the system could detect a nuclear weapon with 99 percent accuracy under specific conditions:

The researcher noted that using multiple satellite sensors could further reduce the detection time to a matter of hours.

Risks of Space-Based Detonations

The need for verification is underscored by the history of high-altitude nuclear tests. In 1962, the U.S. Detonated a 1.4-megaton thermonuclear warhead in space. This blast released enormous volumes of highly energized electrons that became trapped in Earth's magnetic field, destroying many early satellites.

Danagoulian explains that a modern nuclear detonation in low-Earth orbit—the region 100 to 1,200 miles above the surface—would release trillions of electrons. This would likely destroy many current satellites, disrupting GPS, telecommunications networks, space-based internet, and reconnaissance platforms such as Starlink.

Next Steps

Danagoulian emphasizes that the paper is a feasibility study rather than a proven, built system, stating that practical engineering considerations remain. He is currently working with MIT’s Center for Nuclear Security and Policy to analyze the policy implications of the technology.

The project received support from the Carnegie Foundation, Longview Philanthropy, and the National Nuclear Security Administration. Danagoulian's goal is to encourage national labs to adopt the research and for policymakers to integrate the technology into national technical means of verification.

You can fake intelligence, Danagoulian said, but you can’t fake physics.