Towards the deployment of anti-satellite nuclear weapons in space?

(To Valentina Chabert)

In recent weeks, Ohio Republican Congressman and Chairman of the House Intelligence Committee Michael R. Turner urgently informed Congress and, subsequently, European allies, of a imminent threat to the national security of the United States coming from the Russian Federation.1 The alarm would involve the development of a new Russian space nuclear weapon intended to threaten the dense network of US civil, military and intelligence satellites positioned in Low Earth Orbit (LEO), i.e. the orbital band between 300 and 1000 km.

Although a possible deployment does not appear imminent, a weapon of this type – if employed – would have considerable destructive potential for civil communications, space surveillance technologies and military command and control operations of both the US and its allies. A scenario exacerbated by Washington's temporary inability to counter such a device and preserve its satellite infrastructure.2

Two years after the Russian invasion of Ukraine, the shadow of nuclear power in outer space reappears after one of the most tense windows of the conflict in March 2022, when Russian President Vladimir Putin declared his willingness to use the nuclear weapon if enabled to defend Russia's national security. On this occasion, some analysts raised the possibility that Earth orbits could be one of the plausible theaters in which the detonation of a nuclear device, with limited consequences in terms of loss of human life, but disastrous due to the crowding of this orbital belt.3 In fact, it is precisely at those altitudes that the satellites of the private US company are also located Starlink in the hands of the gigacapitalist Elon Musk, which became indispensable for communications on the Ukrainian front after the sending of ground stations to counter Russian attacks on cable communication systems, easy military targets through which 90% of communication passes. At the same time, if the described scenario were to occur, the electromagnetic pulse unleashed by the nuclear detonation would also cause ainstant interruption of all radio signals.

Launching nuclear weapons into space is not a twenty-first century prerogative, as both superpowers conducted experiments of this type in orbit already in the early years of the Cold War.4 It is the case of Starfish Prime, a nuclear test involving the Atomic Energy Commission and the United States Military Atomic Defense Agency on July 9, 1962, within the larger Operation Fishbowl.5 According to British Intelligence reports published by the BBC after being declassified almost fifty years later,6 the nuclear explosion 400 kilometers away from the Pacific Ocean (equal to 1,4 megatons compared to the 15 kilotons of the bomb dropped on Hiroshima) had repercussions as far as Hawaii, located over a thousand kilometers away, causing the interruption of electricity supplies. At the same time, the US test was held responsible for the putting out of use of ariel 1, the UK's first artificial satellite launched into orbit the same year.

For its part, in the same period of time the Soviet Union carried out over 31 nuclear tests in space until the explosion of the so-called Tsar Bomba 50 megatons in 1961, detonated at 4.000 meters above the Arctic Circle. With the progressive easing of relations between the two ideological poles and the success of negotiations in the field of nuclear disarmament, similar experiments in space have no longer occurred since the 1967s, also due to the entry into force in XNUMX of the Treaty on the Principles Governing the Activities of States Concerning the Exploration and Utilization of Outer Space, Including the Moon and Other Celestial Bodies - better known as Outer Space Treaty (OST).7

Under the treaty, any deployment of nuclear weapons as well as any other type of weapon of mass destruction in space is prohibited, with the broader goal of free access, use and exploration of space for peaceful purposes only. Nonetheless, the possible detonation of a nuclear weapon in low Earth orbit in the context of the Russian-Ukrainian conflict would open up new scenarios also from a legal point of view, as it would be characterized as offensive and deterrent act without, however, being directed towards a specific nation in accordance with the prohibition on claims of sovereignty of orbits, outer space and celestial bodies by individual States.

Along this line, if at an operational level the belligerents have resorted to space technology and satellite communication systems Starlink only following the outbreak of the war, there was no lack of deterrence actions in space and cyber attacks on Western satellite systems by the Russian Federation already at the end of 2021. In November, the Russian Ministry of Defense carried out a missile launch aimed to shoot down an out-of-use satellite from the Soviet era, the Kosmos 1408, sparking strong international protests due to the lifting of a cloud of debris into low Earth orbit.8

The destruction of Kosmos 1408, unequivocally interpreted as act of military deterrence, put the entire security system and Starlink technical department on alert, which for months had to carry out continuous maneuvers in order to avoid a possible collision of the satellites with space debris. The Russian Federation, already intending to ban Elon Musk's satellites for national security reasons throughout its territory,9 it then had to defend itself from international accusations according to which the wreckage of the Kosmos 1408 have put the International Space Station in serious danger, whose astronauts were promptly asked to carry out emergency procedures by taking refuge in spaceships Soyuz e Crew Dragon departing for Earth in case the impact occurred.10

If before the conflict in Ukraine the superpowers limited themselves to hitting rival satellites through cyber attacks, electromagnetic disturbance signals (the so-called jamming) and interference,11 the increasingly complex network of satellites in low orbits and the ineffectiveness of cyber operations seem to push in the direction of a disabling or even completely destroying the satellites themselves, with extraordinarily dangerous consequences also for the balance of power between the private companies that enter the sector and the national governments that own satellites in orbit for military purposes.12

A clear example of this is also provided by the progress of China's non-kinetic capabilities and its potential skills acquired in the field of jamming satellite communications, which have become one of Beijing's main priorities, so much so that it has allocated huge resources to the creation of an aerial laser which could conceivably be used against antagonistic satellites.13

The described trends of a possible militarization of space occur in a context of void in terms of international law, as the legal framework applicable to space activities hardly adapts to rapid technological developments, advances in the commercialization of space and the emergence of a broader set of private actors that pose new challenges to the traditional conception of space as the exclusive domain of action government. Especially with regards to the field of security and defense, while the deployment of nuclear weapons in space is expressly prohibited by international space law treaties, no reference is made to other weapons and interference with the space resources of adversary countries, nor to the ban on ground-based ASAT (AntiSATellite, ed.) missiles.14

1 GOP warning of 'national security threat' is about Russia wanting nuclear weapon in space: Sources, ABC News, February 14, 2024. Available at the link:

2 Russia's Advances on Space-Based Nuclear Weapon Draw US Concerns, The New York Times, February 14, 2024. Available at the link:

3 Marcello Spagnulo, The next nuclear bomb could explode in space. In: Limes 9/22, The shadow of the bomb, pp. 45-50.

4 Valentina Chabert, The war in Ukraine is also being fought in space orbit, Opinio Juris – Law and Politics Review, vol. 1, 2023.

5 US Department of State, Office of the Historian. Memorandum of the President's Decisions, June 20, 1962. Foreign Relations of the United States, 1961–1963, Volumes VII, VIII, IX, Arms Control; National Security Policy.

6 BBC, The Cold War nuke that fried satellites, September 2015. Available at the link:

7 UNOOSA, Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, 1967.

8 NASA, Russia tests anti-satellite missile, debris disrupts International Space Station, 15 November 2012. Available at the link:

9 KA Bingen, K. Johnson, ZM Smith, Russia Threatens to Target Commercial Satellites, Center for Strategic & International Studiesyes, 2022.

10 Marcello Spagnulo, The invisible space battle in the Ukrainian war. In: Limes 7/2022, The Great War, pp. 221-226.

11 Viasat, KA-SAT Network cyber attack overview. Available at the link:

12 Valentina Chabert, The outer space dimension of the Ukraine conflict, Columbia Journal of International Affairs, vol. 75, no. 2, pp. 145-156.

13 Stephen Chen, Chinese military scientists claim to have achieved a 'huge breakthrough' on laser weapon technology, South China Morning Post, August 2023.

14 Von Der Dunk FG, Advanced Introduction To Space Law, Edward Elgar Publishing, 2020.