The United States House Intelligence Committee warned in February 2024 of a “serious national security threat.” The committee provided few details publicly, but news outlets soon reported that Russia is developing a space-based nuclear weapon — an anti-satellite system armed with a nuclear weapon. U.S. officials called the possibility a “destabilizing foreign military capability” while also trying to allay public alarm by assuring that the threat isn’t imminent; Russia was not known to have deployed or tested such a weapon. As U.S. officials briefed lawmakers in Washington and Allies in Europe, Moscow denied the claims.
In April 2024, Russia vetoed a United Nations Security Council resolution proposed by Japan and the U.S. reaffirming the Outer Space Treaty and urging countries not to develop space-based nuclear weapons or weapons of mass destruction.
The next month, Russia launched a satellite — Cosmos 2576 — to an orbital plane that U.S. officials said allows it to observe and potentially attack a U.S. government satellite. While not a nuclear weapon, U.S. officials said the satellite is likely a counterspace weapon designed to disable or destroy U.S. space capabilities. Days after that launch, Russia presented its own resolution to the U.N. Security Council, seeking to ban space weapons of any kind. That resolution failed. Some Western nations said they opposed it because of challenges verifying a ban on weapons in space. Then-U.S. Ambassador Robert Wood, at the time deputy permanent representative to the U.N., called Russia’s move “diplomatic gaslighting.”
“We are here today because Russia seeks to distract global attention from its development of a new satellite carrying a nuclear device,” Wood told the U.N. Security Council before the vote. “We have heard President [Vladimir] Putin say publicly that Russia has no intention of deploying nuclear weapons in space. If that were the case, Russia would not have vetoed that resolution.”
U.S. officials have stressed that the weapon Russia is thought to be developing would not be aimed at Earth but at satellites in low Earth orbit (LEO), which is roughly 100 kilometers to 2,000 kilometers in altitude.
A new warfighting domain
In 2019, NATO recognized space as an operational domain and adopted the Alliance’s space policy, recognizing the need to increase Allies’ understanding of the role space plays in crises or conflicts, including nuclear deterrence. That same year, Russia began launching satellites that experts said could be weapons. In one launch, a “nesting doll” satellite released a smaller satellite, and both satellites began following a U.S. National Reconnaissance Office satellite. Several months later, U.S. officials said the smaller satellite released another object, apparently firing a projectile at high speed.
In November 2021, Russia tested a direct ascent anti-satellite (DA-ASAT) missile on one of its own spacecraft, a decommissioned Soviet-era satellite, destroying it and creating a debris field of more than 1,500 pieces, according to U.S. Space Command (USSPACECOM), that could remain in orbit for decades.
“Russia has demonstrated a deliberate disregard for the security, safety, stability and long-term sustainability of the space domain for all nations,” said retired U.S. Army Gen. James Dickinson, Commander of USSPACECOM at the time. “The debris created by Russia’s DA-ASAT will continue to pose a threat to activities in outer space for years to come, putting satellites and space missions at risk, as well as forcing more collision avoidance maneuvers. Space activities underpin our way of life, and this kind of behavior is simply irresponsible.”
The Associated Press
Gen. Dickinson said Russia is developing capabilities to deny other nations access to and use of space. The goal appears to be the focus of Moscow’s nuclear space weapon development.
Conventional counterspace weapons can disrupt a nation’s use of space in multiple ways. Some weapons can use radio frequency signals to interfere with a satellite’s communications, a method called jamming. High-powered microwave weapons can be used to disrupt or destroy a satellite’s electronics. High-powered lasers can temporarily or permanently damage critical satellite components such as optics or solar arrays. Cyberattacks can be used to intercept or corrupt data or seize control of systems. A kinetic attack can damage or destroy physical assets.
Weapons experts say a nuclear attack in LEO would have far-reaching impacts beyond a single target nation.
Space: A nuclear frontier?
In July 1962, the Atomic Energy Commission launched a thermonuclear warhead on the nose of a Thor rocket, creating a suborbital nuclear detonation 400 kilometers above the Pacific Ocean. That exercise, called Starfish Prime, was part of the Operation Dominic series of atmospheric nuclear tests and detonated a hydrogen bomb with a yield of 1.45 megatons, about 100 times more powerful than the atomic bomb dropped on Hiroshima in 1945. The detonation was one of more than a dozen such tests conducted by the then-Soviet Union and the U.S. from 1958 to 1962 but used a far more powerful bomb. Starfish Prime had several objectives, including evaluating the potential to detect and attack intercontinental ballistic missiles and determine radiation impacts on command and control. Scientists also sought an additional metric: They wanted to see if the nuclear warhead could destroy or disrupt the Van Allen belts, two bands of radiation encircling Earth discovered in 1958. Scientists at the time thought the radiation in the belts could inhibit space exploration or be harnessed to attack an enemy.
When the bomb detonated 13 minutes after launch, the electromagnetic pulse was much larger than scientists expected, knocking out electrical and telephone service in Hawaii, 1,600 kilometers away. Viewers in the Fiji Islands, more than 3,200 kilometers from the launch site, could see the bright auroral show in the sky. The blast damaged or destroyed several satellites in orbit. In addition, scientists learned that the blast added radiation to the Van Allen belts instead of disrupting them.
The fallout from Starfish Prime and other orbital nuclear tests led to a de-escalation of nuclear weapons development. In August 1963, the Soviet Union and the U.S. signed the Limited Nuclear Test Ban Treaty, in which the two nations agreed not to test nuclear weapons in the atmosphere, in space or under water. In 1967, the two countries signed the Outer Space Treaty, which bans the stationing of nuclear weapons and other weapons of mass destruction in space and prohibits military activities on celestial bodies.
“The Starfish Prime shot is sort of the poster child for why we don’t like nukes blowing up in space,” Jonathan McDowell, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian told Scientific American magazine.
“The concept that we are concerned about is Russia developing — if we are unable to convince them otherwise — to ultimately fly a nuclear weapon in space, which would be an indiscriminate weapon,” John F. Plumb, former assistant secretary of defense for space policy, said at a May 2024 U.S. House Armed Services Committee hearing. “This capability could pose a threat to all satellites operated by countries and companies around the globe, as well as to the vital communications, scientific, meteorological, agricultural, commercial and national security services we all depend upon.”
A nuclear attack in LEO — the most common orbit for satellites — could devastate the nearly 10,000 satellites in orbit that enable communications, navigation and other functions for military, commercial and civil entities. Any nation that depends on satellite technology would be affected. Electrical grids could fail, cellphone and other communication could stop working. Aviation and land transportation would come to a halt.
A high-altitude electromagnetic pulse (HEMP) from a nuclear detonation beyond 30 kilometers above the Earth’s surface would have both instant and long-term effects, according to a June 2024 paper from Victoria Samson and Seth Walton from the Secure World Foundation, a private foundation that promotes peaceful use of space. The instant effect is exposure to X-ray, gamma and ultraviolet photons from the detonation. These effects occur immediately upon detonation and cause damage to satellites with direct line of sight to the detonations. The protective coatings of affected solar cells will be damaged or destroyed, meaning affected satellites can experience partial or total loss of power generation. The semiconductors in circuits onboard spacecraft will also be damaged, which can cause short-circuiting, known as latch-up, where the impacted components burn out and lose functionality. These combined effects could severely damage or completely disable any satellite within line of sight.
The enduring effect from a HEMP is radiation exposure from trapped ionized particles. A HEMP blast releases large amounts of charged particles into space, which can be trapped by Earth’s magnetic field and significantly amplify the radiation of the Van Allen belts for an extended time. The trapped particles will eventually diffuse, taking roughly 30 days for geosynchronous Earth orbit (roughly 36,000 kilometers in altitude) and nearly 300 days for LEO.
A nuclear attack in space would also create a massive debris field, putting in-space assets at risk long-term.
Rattling the saber
Building a space-based nuclear weapon would be just one of several recent moves by Putin to brandish the nuclear sword as he attempts to deter the West from increasing support for Ukraine. In June 2024, Belarus and Russia conducted tactical nuclear weapons drills. That same month, Putin called for Russia to resume production of ground-based intermediate-range missiles banned under the now-scrapped Intermediate-Range Nuclear Forces Treaty. In September 2024, Putin lowered the threshold of nuclear response by revising the country’s nuclear doctrine. The next month, Russia launched a massive exercise of the country’s nuclear forces featuring missile launches in a simulation of a retaliatory strike.
A space-based nuclear weapon would violate the Outer Space Treaty, but it is unclear what, if any, consequences Russia or any other nation would face if they built one, said Sharon Squassoni, a professor of international affairs at George Washington University.
“There are no treaty-prescribed consequences of noncompliance, but states could choose to impose sanctions related to this,” Squassoni told Space.com. “Another complication is whether we know what the capability is until Russia actually uses it. If we do have excellent intelligence, are we willing to share it to make the case for imposing costs on Russia? Not clear.”
Putin will likely reject any steps related to transparency in weapons buildup while Russia is still at war with Ukraine, she said.
“The weaker a state is in its conventional military force, the more it will rely on nuclear weapons,” Plumb said in an interview with SpaceNews magazine. “Russia is exhausting a lot of their conventional force on the Ukrainian front.” He said hardening all U.S. satellites against the radiation from a space-based nuclear attack would be unrealistic and prohibitively expensive. Instead, the U.S. Department of Defense (DOD) and other U.S. government agencies should do further studies and modeling of the potential impact of a nuclear detonation in orbit and develop options to increase the resilience of military systems.
The quickly evolving threat in space was one of the main drivers behind establishing the U.S. Space Force, then-DOD spokesman Maj. Gen. Pat Ryder said at a briefing in February 2024, according to The Associated Press (AP). In the years since its 2019 creation, the service has focused on developing a curriculum to train its service members, called Guardians, on detecting threats from space and war-gaming scenarios on what conflict in space would look like.
The creation of the Space Force elevated spending on satellite systems and defenses. Previously, when space needs were spread among the military services, spending on a new satellite would have to compete for funding with ships or fighter jets — and the services had a more immediate need for the aircraft and vessels, John Ferrari, a nonresident senior fellow at the American Enterprise Institute, told AP. There remains more work to be done, and the revelation that Russia may be pursuing a nuclear weapon for space raises critical questions for U.S. lawmakers and the DOD, he said. If Russia uses a nuclear weapon to take out satellites and cripple the U.S. economy, does that justify the U.S. bombing Russian cities in return?
“How do you respond to that? You have no good option,” Ferrari said. “So now it’s a question of, ‘What is the deterrence theory for this?’ ”