MIT Researcher Proposes New Way to Detect Nuclear Weapons in Space

Addressing the 60-Year Verification Gap in the Outer Space Treaty

When the United States and the Soviet Union signed the Outer Space Treaty in 1967, both superpowers agreed not to place nuclear weapons or other weapons of mass destruction in orbit around Earth. Article IV of the treaty was specifically formulated to prevent the nuclear arms race of the Cold War from spilling over into the cosmos. However, neither side has ever had a reliable way to confirm that the other is keeping its word. According to Jeffrey Lewis, a nuclear nonproliferation expert and distinguished fellow at the Foreign Policy Research Institute, the treaty lacks teeth and operates effectively as a gentleman’s agreement. That lack of verification has remained largely a theoretical gap for nearly six decades. But as Jeffrey Lewis notes, the honor system faces renewed pressure because the United States heavily depends on space capabilities for military power, and Russia is actively exploring ways to neutralize those capabilities. The concern intensified following the 2022 launch of Russia’s Kosmos 2553 satellite. The satellite later began to tumble and make erratic movements.

How the Proposed Satellite Detection System Works

The new MIT feasibility study outlines how an encyclopedia-sized detector equipped with specialized sensors could spot a hidden warhead. As described in the study, the detector would search for neutrons produced when charged particles interact with radioactive elements inside a weapon. When a satellite carrying uranium or other radioactive materials passes through regions of high-energy protons trapped by Earth’s magnetic field, these protons strike the radioactive material, ejecting neutrons.

According to Danagoulian’s calculations, a detector could identify neutrons emanating from the direction of a potential warhead from about 2.5 miles or 4 kilometers away after roughly a week of observation. Closer range observations would yield faster detections.

Diplomatic Hurdles and Strategic Risks in Orbit

Even if the technical hurdles are cleared, experts emphasize that policy and diplomatic challenges remain far more daunting. Getting an inspector satellite close enough to observe another spacecraft—and maintaining that proximity for a week—would require positioning satellites much closer than normal, which could easily trigger fears of espionage or attack. Thomas González Roberts, an assistant professor at the Georgia Institute of Technology who studies outer space governance, told Live Science that satellite operators get really freaked out when another spacecraft spends too much time nearby.

Brian Weeden, director of civil and commercial policy for the Center for Space Policy and Strategy at Aerospace Corp., notes that any functional inspection mechanism would necessitate cooperation from the target nation, thereby introducing intricate dilemmas concerning international protocols for satellite checkups. Weeden told Live Science that in his experience, policy problems are always a bigger challenge than technical problems. Furthermore, Roberts noted that deliberate nuclear damage to satellites remains rare because it is obviously a bad idea. An attacker using a nuclear weapon in orbit would likely damage their own large satellite fleet as well, meaning nations with much to lose in space have strong disincentives against such attacks.

The Growing Vulnerability of Modern Space Infrastructure

The stakes for preventing any orbital detonation are higher now than they were during the Cold War. In 1962, when the U.S. conducted the 1.45-megaton Starfish Prime high-altitude test 250 miles above the Pacific Ocean, only 24 satellites were in orbit. That historic blast knocked out radio communications for hours, created auroras visible from Hawaii, damaged or destroyed eight satellites including Telstar 1 and Ariel 1, and left radiation lingering in orbit for five years.