A new analysis by researchers from the prestigious Massachusetts Institute of Technology has raised fresh concerns about Russia’s controversial nuclear-powered Burevestnik cruise missile, known by NATO as the SSC-X-9 Skyfall. According to the study, the weapon may disperse radioactive material throughout its flight, potentially contaminating the atmosphere and the terrain below wherever it travels.
The findings come from aerospace and nuclear engineering specialist Jake Hecla and co-author R. Scott Kemp, who conducted one of the most detailed open-source examinations yet of the missile’s propulsion system. Their conclusions provide new insight into a weapon that has remained shrouded in secrecy since Russian President Vladimir Putin first unveiled it in 2018 as part of a new generation of strategic weapons.
The Burevestnik occupies a unique position among modern military systems. While conventional cruise missiles rely on jet engines powered by chemical fuel, Russia has repeatedly claimed that the Burevestnik uses a miniature nuclear reactor. Such a design would theoretically grant the missile an almost unlimited range, allowing it to remain airborne for extremely long periods and approach targets from unexpected directions.
For years, however, analysts questioned whether Russia had actually achieved such a breakthrough. The engineering challenges involved in building a practical nuclear-powered aircraft are immense, and several previous efforts by both the Soviet Union and the United States failed to produce an operational weapon.
The new MIT study argues that Russia may indeed have succeeded in flying a nuclear-powered missile, but at a potentially significant environmental and safety cost.
The concept of nuclear-powered aviation dates back to the early years of the Cold War. During the 1950s, both the United States and the Soviet Union investigated whether nuclear reactors could power aircraft capable of remaining aloft for weeks or even months.
The United States tested a reactor aboard the Convair B-36 Peacemaker, while the Soviet Union conducted similar experiments using the Tupolev Tu-95 Bear. In both cases, the reactors were carried onboard for testing purposes but never directly powered the aircraft’s engines.
One of the most ambitious American efforts was Project Pluto. Developed during the 1950s and 1960s, Pluto aimed to create a nuclear-powered cruise missile capable of flying at extremely low altitude and supersonic speed. The missile would carry multiple nuclear warheads and travel deep into enemy territory.
Project Pluto successfully tested a ground-based reactor in 1964, demonstrating that the basic concept could work. Nevertheless, the program was eventually canceled due to concerns about practicality, cost, environmental contamination, and the emergence of more effective ballistic missile technologies.
For decades afterward, nuclear-powered aircraft and missiles remained largely theoretical concepts.
That changed dramatically in 2018 when Putin unveiled several advanced strategic systems during a nationally televised address. Among them was the Burevestnik cruise missile.
The missile was presented as one of six revolutionary weapons designed to overcome Western missile defenses. Other systems included hypersonic weapons and the nuclear-powered underwater drone known as Poseidon.
Russian officials claimed that the Burevestnik possessed virtually unlimited range and could maneuver unpredictably around missile defense networks. The weapon was portrayed as a strategic game-changer capable of reaching targets from almost any direction.
Many Western analysts initially viewed the claims with skepticism. The absence of confirmed successful tests and the extraordinary engineering requirements led some observers to wonder whether the program was more propaganda than reality.
The missile’s development history has been marked by incidents that fueled concerns about its nuclear propulsion system.
Shortly after Putin’s announcement, the environmental organization Bellona Foundation suggested that unusual radiation readings detected in the Arctic during the winter of 2018 may have been connected to a Burevestnik test.
Further questions emerged when U.S. intelligence assessments reportedly indicated that a Russian nuclear-powered missile had been lost at sea during a 2017 test. According to those reports, Russian authorities later planned a recovery operation to retrieve the wreckage from the seabed.
The most serious incident occurred in August 2019 near the village of Nenoksa on Russia’s White Sea coast. An explosion aboard a floating platform killed five scientists employed by Rosatom.
The blast also triggered a temporary radiation spike in the nearby city of Severodvinsk, prompting international concern.
Although Russian authorities never fully clarified the nature of the accident, many experts linked it to Burevestnik-related activities. One prevailing theory suggested that the explosion occurred during an attempt to recover a reactor from a missile lost during earlier testing.
A significant development came in October 2025 when Valery Gerasimov announced that the missile had successfully completed a lengthy test flight over the Arctic.
According to Gerasimov, the missile remained airborne for approximately 15 hours. He also indicated that the flight duration did not represent the system’s maximum capability.
The MIT researchers regard this test as highly significant. In their assessment, the reported performance suggests that Russia may have achieved something that neither the United States nor the Soviet Union managed during the Cold War: sustained flight powered by a nuclear reactor.
If confirmed, the achievement would represent a major milestone in aerospace engineering.
The central question addressed by the MIT study concerns the mechanism through which the Burevestnik converts nuclear energy into thrust.
By examining publicly available imagery and comparing dimensions visible in photographs and videos, Hecla and Kemp estimated that the missile is roughly 9.5 meters (31 feet) long with a wingspan of approximately 5.6 meters (18 feet).
The researchers believe the missile cruises at around Mach 0.75, placing it firmly in the subsonic category.
This is an important observation because it suggests the Burevestnik differs significantly from the supersonic nuclear-powered missiles envisioned under Project Pluto.
Pluto relied on a ramjet engine that required high speeds to operate effectively. Air would pass directly through a reactor, become intensely heated, and then exit through a nozzle to generate thrust.
The Burevestnik, by contrast, appears better suited to a turbojet-based design.
According to the researchers, the missile almost certainly uses what is known as a direct-cycle air-breathing nuclear propulsion system.
In such an arrangement, atmospheric air is drawn into the engine and forced through thousands of narrow channels surrounding nuclear fuel elements within the reactor core.
As nuclear fission generates heat, the passing air becomes extremely hot. The heated air expands and exits through the rear of the engine, producing thrust in much the same way as a conventional jet engine.
The design offers major advantages in terms of simplicity and compactness.
Unlike conventional nuclear reactors, which use sealed coolant systems to transfer heat indirectly, a direct-cycle reactor allows air to flow straight through the reactor core itself.
This eliminates the need for heavy heat exchangers, pumps, and complex plumbing systems.
For a missile constrained by size and weight limitations, such efficiency is highly attractive.
The same feature that makes the design practical may also make it dangerous.
Because air passes directly through the reactor, it can become contaminated by radioactive byproducts generated during nuclear fission.
Hecla argues that this process would likely release radioactive isotopes into the atmosphere through the engine exhaust.
Among the substances that could be emitted are radioactive forms of argon, krypton, and carbon. These materials would then disperse along the missile’s flight path.
The researchers suggest that every hour of flight could result in additional radioactive contamination being released into the environment.
This concern is not entirely new. During the Cold War, environmental risks associated with direct-cycle nuclear propulsion were among the primary reasons Western governments ultimately abandoned similar concepts.
A missile capable of flying for many hours or days could potentially leave a lengthy trail of radioactive material behind it.
The MIT study identifies another potential challenge: reactor degradation.
Operating a reactor under conditions of extreme heat while continuously exposing it to compressed atmospheric air can gradually damage internal components.
Over time, corrosion may develop within the reactor core, eroding protective materials and releasing additional radioactive particles.
Such degradation could not only increase environmental contamination but also limit the practical endurance of the missile itself.
This observation challenges one of the Burevestnik program’s most heavily promoted features—its supposed unlimited range.
While the missile may remain airborne far longer than conventional cruise missiles, maintaining reactor integrity indefinitely presents a significant engineering obstacle.
The researchers also believe their analysis may help explain the fatal White Sea incident.
According to their assessment, Russian personnel may have been attempting to recover a submerged prototype reactor when an unexpected restart occurred.
If the reactor became active while being lifted from the seabed, it could have generated intense heat and pressure, potentially causing the explosion that killed the Rosatom scientists.
Although definitive proof remains unavailable, the scenario aligns with many of the known facts surrounding the accident.
It would also underscore the difficulties associated with handling nuclear-powered missiles during testing and recovery operations.
The Burevestnik’s strategic value remains a matter of debate.
Its greatest strength is undoubtedly its extraordinary range.
Traditional cruise missiles must contend with fuel limitations. A nuclear-powered missile could theoretically circle vast areas, remain airborne for extended periods, and approach targets from unexpected directions.
For example, a missile launched over the Arctic could spend many hours maneuvering before approaching North America from the south, potentially bypassing certain radar and missile defense systems.
Its unpredictable trajectory could complicate defensive planning and increase pressure on early warning networks.
This capability has attracted significant interest among military planners concerned with strategic deterrence.
Despite its unique range advantages, the Burevestnik appears to possess several significant weaknesses.
First, it is relatively slow. Traveling at roughly three-quarters the speed of sound, it lacks the velocity of hypersonic weapons and advanced ballistic missiles.
Second, once detected, it may not be especially difficult to intercept.
Third, if the missile truly emits radioactive exhaust, it could generate a detectable signature that assists tracking efforts.
Perhaps most importantly, Russia has consistently portrayed the Burevestnik as a nuclear delivery system.
Using such an expensive and technologically complex missile for conventional missions would likely make little sense, particularly if its propulsion system creates environmental hazards regardless of payload.
Some defense experts remain unconvinced that the missile offers sufficient benefits to justify its costs and risks.
William Alberque, formerly responsible for strategy, technology, and arms control issues at the International Institute for Strategic Studies, has been particularly critical.
Alberque argues that the concept suffers from multiple shortcomings. According to his assessment, radiation leakage could make the missile easier to detect, while its subsonic speed leaves it vulnerable to interception. At the same time, degradation inside the reactor raises questions about the practicality of truly unlimited endurance.
His criticism reflects a broader view among many Western analysts that the challenges associated with nuclear-powered cruise missiles outweigh their strategic benefits.
Hecla and Kemp propose that the Burevestnik may serve a purpose beyond its immediate military role.
Rather than being solely a deployable weapon, the missile could function as a testbed for technologies that might later be applied elsewhere.
Potential future applications include long-endurance surveillance drones, advanced autonomous systems, or even certain space-based nuclear platforms.
Developing compact, lightweight nuclear propulsion systems could have implications across multiple military and aerospace sectors.
Another possibility is that the program reflects a strong political commitment from Putin himself, who has frequently emphasized advanced strategic technologies as symbols of Russian scientific and military achievement.
If the MIT analysis is correct, the successful October 2025 test represents a remarkable milestone. For the first time in history, a nuclear-powered aircraft may have completed sustained flight using a functioning onboard reactor.
From a technological standpoint, that achievement is extraordinary.
Yet the accomplishment comes with significant caveats. The same design features that enable long-duration flight may also create environmental hazards, operational risks, and strategic limitations.
Questions remain about radioactive emissions, reactor durability, accident risks, and overall military effectiveness.
The Burevestnik stands as both an engineering breakthrough and a controversial experiment—one that highlights the enduring tension between technological ambition and the safety concerns that have long accompanied nuclear-powered flight.
