If confirmed, rumors that Russia intends to use nuclear weapons against satellites would force the West, China and commercial companies to come up with protective measures, while Washington and Beijing would also need to adapt their deterrence strategies vis-a-vis Moscow. The chairman of the U.S. House Intelligence Committee, Republican Rep. Mike Turner of Ohio, said on Feb. 14 that he and other members of Congress had received new intelligence from the administration of U.S. President Joe Biden regarding a ''serious national security threat.'' While he declined to provide more information, he called on the Biden administration to declassify the intelligence to enable Washington to better coordinate with its allies on the matter. According to subsequent reporting by several U.S. media outlets, the threat appears to be related to Russia's development of nuclear anti-satellite (ASAT) weapons. However, reporting on the device's type is inconsistent, as at least one reputable U.S. media outlet has described the device as a nuclear-powered satellite that could carry out electronic warfare, which while still very concerning to the United States, would not be as destabilizing to the U.S. national security as a nuclear-tipped ASAT weapon. The United States has reportedly been concerned about Russia's development of nuclear ASAT weapons for over a year and one member of Congress called the new space threat capability a ''geo-strategic game changer.'' Congressman Turner's remarks about the information come just days after Russia on Feb. 9 launched a military satellite into orbit that the Russian Aerospace Force has since taken control of, though it is unclear if his comments were related to the launch.

• Turner's comments forced White House National Security Advisor Jake Sullivan to hold an impromptu press conference in which he said he was ''surprised'' Turner went public with the remarks. Sullivan told reporters he was already planning to hold a bipartisan meeting with senior leaders of Congress on Feb. 15 to brief them on the matter, but said he could not elaborate further on the threat. 
• U.S. officials have said that the new intelligence does not represent an immediate concern. While Turner's decision to go public about the threat may be a sincere attempt to improve the United States and its allies' response to it, speculation has mounted that he may have had an additional ulterior motive. Turner has been one of the most vocal Republican House members calling on Speaker Mike Johnson to put up to vote a bill to send more aid to Ukraine for its fight against Russia, and by amplifying the strategic threat Russia poses, he could be trying to further pressure the Republican House leadership to pass such a bill.
• PBS NewsHour reported the mystery weapon was possibly a nuclear-powered satellite with ''an electronic warfare capability to target American satellites.'' Such a satellite could be used in a more targeted fashion compared with the weapon being described in other outlets, including The New York Times (which said the device was a ''new, space-based nuclear weapon''), The Wall Street Journal (which characterized it as a ''nuclear weapon in space that could be used to target satellites''), and The Washington Post (which noted Russia may be developing a ''space-based military capability that [could damage] critical intelligence or communications satellites with a nuclear weapon''). 

The development of a Russian nuclear-powered or nuclear propulsion ASAT would be less damaging to U.S. national security than a nuclear-tipped ASAT weapon, but it would still mark a significant step in the weaponization of space and prove difficult for the United States and its allies to defend against. The publicly known Russian project that appears to most fit this description is Russia's Transport and Energy Module (TEM), known as ''Zeus.'' Often referred to as a space tug, once completed, the TEM will use nuclear electric propulsion, wherein thermal energy from a nuclear reactor is converted to electrical energy that is then used to drive the ship's ion thruster for propulsion while also powering other components of the spacecraft. Energy generated by the TEM's onboard nuclear reactor could also potentially power electronic warfare weapons, electromagnetic pulse weapons, or directed energy weapons (i.e., lasers). In recent years, Russian media outlets have reported that the spacecraft's nuclear reactor could have a dual-use application to power anti-satellite weapons as well. Such a weapon would be able to knock out individual U.S. satellites near its orbit that carry out a variety of functions, such as capturing imagery and other data for the U.S. military for use on land. 

• Russia is not the only country researching nuclear-powered or nuclear-propulsion rockets and satellites. In July 2023, the U.S. ​​Defense Advanced Research Projects Agency awarded Lockheed Martin with a contract to develop a nuclear-powered spacecraft that would create thrust for a rocket by using nuclear power to quickly heat hydrogen propellant. The project, which is under DARPA and NASA's Demonstration Rocket for Agile Cislunar Operations (DRACO) project, aims to have an in-space flight demonstration by 2027. China has also expressed a desire to use nuclear power to power its planned lunar base. 

However, in the less likely case that the weapon uses a nuclear explosion, it would represent a significant threat to virtually all satellites in low earth orbit, especially lightly protected commercial satellites. National security analysts have known for years that a detonation of a large nuclear device at a high altitude could cause significant damage to satellites in low earth orbit. First, the detonation itself would send out a powerful electromagnetic pulse that would destroy virtually all satellites within line-of-sight in low earth orbit that would be unshielded from such pulses. Second, the explosion would leave behind an artificial radiation belt that would last for months to years, damaging other unshielded satellites moving in and out of the belt as they continue their own orbits. The exact scale and nature of the impact of these two phenomena would depend on various factors, including the intensity of the explosion and electromagnetic pulse, as well as the explosion's location and altitude. This threat contrasts with that posed by TEM or another nuclear-powered ASAT, which would primarily threaten individual satellites. 

• Low earth orbit is becoming increasingly crowded with satellites and manned spacecraft amid the privatization of space, which has enabled a growing number of companies to send small, cheap satellites into space for a variety of reasons — and the vast majority are being inserted into low earth orbit, which is home to 85% of all satellites. SpaceX's Starlink internet satellite constellation alone accounts for over half of all the satellites deployed in orbit. These small and cheap commercial satellites are generally built to only protect against the radiation effects typically encountered in low earth orbit, which are more limited than higher orbits or interplanetary travel, making them susceptible to a nuclear explosion at a higher level. 
• Satellites flying at a higher altitude are equipped with more protection. Many military and intelligence satellites, including even those placed in low earth orbit, are also already more heavily shielded against increased radiation threats and electromagnetic pulses. While it's possible that Russia is developing a similar weapon that can deployed in other orbits, such a weapon may be less effective given the lower number of satellites in such orbits, and the fact that satellites at higher altitudes are better protected from radiation effects due to their typically stronger shielding, even if there's a higher percentage of crucial U.S. military and intelligence satellites. 
• In the 1960s, the United States detonated five explosions under Operation Fishbowl. The most notable test conducted as part of that operation, Starfish Prime, damaged at least a third of the 24 satellites in orbit and had a more significant impact than what U.S. officials expected at the time. Notably, the Starfish Prime detonation led to the early demise of the world's first communications satellite, Telstar 1, which was launched the day after the detonation — demonstrating the lingering effects of the explosion, as the Telstar 1 satellite encountered an artificial radiation belt left behind by the nuclear test, causing damage to its solar cells and other electronic components. 

Russia's development of a space-based nuclear capability would confirm that its strategic calculus regarding collateral damage caused by ASATs is changing, especially if the new weapon can detonate a nuclear blast. The damage caused by a high-altitude nuclear explosion would be indiscriminate, meaning that whoever launched the weapon would be unable to protect their own satellites. Many national security analysts have thus long assumed that space-faring powers — including Russia — would not carry out such an attack due to the damage it'd cause to their own equipment; under this view, only a rogue state with nuclear weapons, space capabilities and a limited dependence on space, like North Korea, might consider setting off a high-altitude nuclear blast. This assumption was likely true for the Soviet Union during the Cold War, when the Americans and the Soviets were both dependent on space capabilities in low earth orbit. But over the last decade, Russia's dependence on space has fallen well behind that of the United States and NATO, as has its space capabilities. Russia was once one of the largest space launch providers for commercial satellites, but it has since been usurped by SpaceX's emergence in the last decade. Russia has virtually no answer to the rise of Elon Musk's U.S.-based company (and the use of Starlink by Ukrainian military forces), and has also fallen behind China in terms of commercial space capabilities. As such, Moscow's cost-benefit analysis when it comes to disrupting access to space today looks very different than it did a decade ago, as it now has much less to lose compared with its adversaries in the West. Indeed, Russia has already demonstrated a higher tolerance for disrupting access to low earth orbit with renewed research into kinetic ASATs, which risk creating a debris field that can affect other satellites indiscriminately. Over the last decade, Russia has carried out at least seven test flights of kinetic ASAT weapons, including the November 2021 use of an anti-satellite missile to destroy the Kosmos 1408 satellite, which created a large debris field requiring the International Space Station to carry out an orbital maneuver to avoid it. 

• The risk of collateral damage likely remains a deterrent for China when it comes to using nuclear weapons in space. China is far more dependent commercially on its space sector than Russia, and in recent years, Beijing has proven to be more risk-averse when it comes to taking national security risks that could damage its own economic health. 
• If Russia were to detonate a high-altitude nuclear explosion, it would have to consider the risk of damaging its relations with China, which would be affected just as much as the United States. Russia would thus likely only launch such an attack in a military confrontation with the West where relations with China are already damaged, or in a military confrontation with China itself. 
• Russia's research into nuclear ASATs, as well as kinetic ASATs, is fueling speculation that Russia may also exit the 1967 Outer Space Treaty, which explicitly bars the use of nuclear weapons and deploying them in space. 
• The New START treaty, the primary and final remaining strategic arms control treaty between Russia and the United States, expires in February 2026. If the treaty is not replaced, Russia could increasingly threaten to leave the 1967 Outer Space Treaty as well, which would enable Moscow to more credibly threaten to use nuclear and anti-satellite weapons in space. 

If Russia aims to possess nuclear ASATs and threatens to use them, it would be a game changer in terms of space-based national security threats, and would force the United States, China and other countries to install more robust protections. If Russia is seen as a credible threat to the safety of satellites in low earth orbit, the global military and commercial actors will have to react to try to limit the impact and deter the threat. Developers of new satellites would probably try to harden their shielding to radiation and other threats and consider whether to use a different orbit, like medium earth orbit, that high-altitude nuclear explosions would not affect. However, having satellites in such orbits is not only more costly but less suitable for many applications (such as for satellite imagery, which would have to be taken at a longer distance from Earth's surface, reducing the image's quality). Companies that are particularly concerned about the threat may be forced to look into replacing some existing mission-critical satellites with more hardened satellites, which is often expensive. The U.S. government, meanwhile, may have to consider placing more satellites at a higher orbit to protect them, as well as ways to streamline the emergency use of other options, such as land-based solutions. To deter Russia from conducting a high-altitude nuclear attack, the United States would also need to come up with a clear strategy for how it'd respond to such an attack that ensures the cost to Moscow is proportional to the cost to the West.

• The United States has long made it clear to Russia that an attack on nuclear command, control and communication (NC3) satellites — which are essential for the United States nuclear triad and detection of a nuclear attack against the United States, as well as launching its own nuclear counterattack — could trigger a nuclear war as the United States would not be able to determine if such an attack was an opening salvo to a nuclear attack. These concerns are not entirely new and have long been referenced in U.S. nuclear posture documents of things Washington could consider. But the threat may now be more realized than ever before if Russia is developing and potentially deploying nuclear ASATs for use.