2025 Skyfall test spewed radiation for hours: First nuclear-powered flight, MIT says

For the space and defense industry, the successful atmospheric flight of a nuclear-powered cruise missile shatters a long-standing technological barrier. While commercial space ventures explore nuclear thermal propulsion for interplanetary travel, Russia’s weaponization of the technology for a loitering weapon introduces an unshielded radiation hazard that could force a redesign of satellite tracking, missile defense, and international arms control frameworks.

The October 21, 2025 test of Russia's nuclear-powered Burevestnik cruise missile—NATO-designated Skyfall—represents a perilous milestone in aerospace weaponry. According to a newly published analysis by MIT researchers Jake Hecla and R. Scott Kemp, the flight not only achieved the first sustained nuclear-powered atmospheric flight in history but did so with a reactor design that deliberately spews radioactive fission products across its path. The missile launched from a Russian island in the Arctic, flew northeast, then executed hours-long loitering loops over frozen terrain, demonstrating the unlimited range and unpredictable attack angles that have made nuclear propulsion a holy grail for military strategists since the Cold War.

“

The October 21, 2025 test of Russia's nuclear-powered Burevestnik cruise missile—NATO-designated Skyfall—represents a perilous milestone in aerospace weaponry.

The MIT team’s modeling, drawn from publicly available data and observed test behaviors, indicates the Skyfall employs a direct-cycle nuclear ramjet. In such a design, incoming air passes through the reactor core itself, heating it to produce thrust without the heavy shielding needed to contain radiation. The result is a plume of xenon, krypton, and other fission products trailing the missile throughout its flight. Hecla called the weapon 'wildly expensive and very dangerous,' emphasizing that the October test alone posed 'enormous risk' to anyone near its path—including Russian personnel and Arctic communities.

This breakthrough did not emerge in a vacuum. Since 2001, Russia has invested heavily in exotic strategic systems to evade U.S. missile defenses, including hypersonic glide vehicles and nuclear-powered cruise missiles. The Skyfall, also known as 9M730 Burevestnik, was revealed by President Vladimir Putin in 2018 and has suffered a troubled development history, including a 2019 explosion in Nyonoksa that killed five scientists and released radiation. The October 2025 flight, however, proves the program has overcome at least some of its earlier failures. Past U.S. and Soviet nuclear aircraft efforts—most famously the U.S. Convair NB-36H Crusader, which carried an operating reactor but never used it for propulsion—failed to achieve actual powered flight. The Skyfall’s loitering hours over the Arctic thus mark a genuine technological first.