Russian Nuclear Weapons in Space


| Feb 16, 2024

Nuclear Weapons

Recent news reports indicate that U.S. authorities fear Russia “wants to put,” a nuclear weapon into space, with U.S. intelligence describing this as a “serious security threat.” The suggested possible purpose of the weapons would be to target Western satellites in space, thereby taking out communications and military targeting systems. Reports suggest that the nuclear weapons would not be used against ground targets.

The Outer Space Treaty

As Dr. Malcolm Davis of the Australian Strategic Policy Institute has already pointed out, deploying nuclear weapons in orbit would be a violation of the Outer Space Treaty. The most relevant provision of that treaty is Article IV which provides, so far as relevant, “States Parties to the Treaty undertake not to place in orbit around the earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.”

Much will, of course, turn on the quality of the intelligence, exactly which technologies the weapons concerned employ, whether the weapons in fact amount to nuclear weapons, and exactly how Russia intends to deploy them. If Russia’s wish or plan is indeed to put a nuclear weapon into outer space in the sense of placing it in orbit around the Earth, for example, or if Russia intends to place such weapons on celestial bodies or, a third possibility, if the idea is to station the nuclear weapons in outer space in any other way, Russia would thereby be acting in direct breach of the Outer Space Treaty. The term “celestial bodies” is referred to in the Outer Space Treaty but is not defined. It appears to refer to all heavenly bodies apart from the moon.

Interestingly, there are three depositary governments that are collectively responsible for the administration of the treaty. Those are the governments of the United Kingdom, the United States, and of the Russian Federation. The three governments opened the Treaty for signature in January 1967 and it entered into force in October the same year. The Union of Soviet Socialist Republics ratified the treaty on 10 October 1967 with immediate effect.

The UN Charter

There will be those who wonder whether, were Russia actually to take the action mentioned in the reports, this would amount to a breach of UN Charter law. The relevant provision would likely be Article 2(4) of the UN Charter which stipulates, “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.”

If one State deploys a nuclear weapon into outer space and uses it to damage or destroy a satellite belonging to another State, there is no doubt that such an act would be regarded as a use of force in breach of Article 2(4). Depending on the nature and national importance of the services that the attacked satellite provides, the effects of the attack on the continued provision of those services, and the degree of damage, destruction, injury, and death ensuing as a result of the termination of those services, it is entirely plausible that such an attack might also amount to a “most grave form” of a use of force (para. 191). In these circumstances, it would constitute an armed attack to which the victim State would have the right to respond by taking forceful action in self-defence, subject to considerations of proportionality and necessity. It should also be noted that the victim State has the right to take forceful action in self-defence if an armed attack occurs or is imminent and that the forceful action in self-defence must comply with the immediacy requirement.

Perhaps the more difficult question is whether the stationing of a nuclear weapon in Earth orbit in clear breach of Article IV of the Outer Space Treaty would also amount to a threat to use force. This is a significant question because a threat to use unlawful force is also a breach of Article 2(4) of the UN Charter, thereby giving the victim State the right to take non-forceful countermeasures in response. To be an unlawful threat, the threatened action, were it to be carried out, must amount to an unlawful use of force.

Imagine a situation in which State A wants State B to cede part of its eastern territory to State A. If State A were to station a nuclear weapon in orbit around the earth and if State A then threatened State B that if it did not cede that territory, State A would use the nuclear weapon to destroy State B’s satellite system, that would be an unlawful threat to use unlawful force and would breach Article 2(4). Moreover, if the attendant circumstances indicate that an attack of that severity is imminent, the victim State may have the right to take forceful action in self-defence on the basis of the imminent armed attack.

To amount to an unlawful threat, however, there must be an expression of an intention. The essence of a threat is that it is explicitly or impliedly communicative in nature (see Tallinn Manual 2.0, commentary to rule 70, para. 4). As I have written previously with Wolff Heintschel von Heinegg,

If a State merely acquires the capability to use nuclear force, this does not constitute an unlawful threat as no express or implied threat is being communicated. However, if, for example, the political leadership of the State were to publicly disclose that it has obtained the means to use a nuclear weapon and intends to use it against a named State unless that State takes specified action or desists from stated activities, that would constitute a threat to use unlawful force (p. 37).

In the present situation, the reports suggest that no relevant statements, threatening or otherwise, have been made by the Russian government. The issue then turns on whether the possession and deployment of such a capability into outer space is impliedly communicating a threat. If the deployment action is merely being taken as a precaution, as it were, with no intent to use the weapons on any particular occasion or against any particular country, it may be difficult to distinguish such a deployment from the nuclear deterrent policies maintained by a number of powerful countries, including the permanent five (P5) States on the UN Security Council. It should be recalled that in its Nuclear Weapons Advisory Opinion in the mid-1990s, the International Court of Justice (ICJ) addressed nuclear deterrence as follows,

Some States put forward the argument that possession of nuclear weapons is itself an unlawful threat to use force. Possession of nuclear weapons may indeed justify an inference of preparedness to use them. In order to be effective, the policy of deterrence, by which those States possessing or under the umbrella of nuclear weapons seek to discourage military aggression by demonstrating that it will serve no purpose, necessitates that the intention to use nuclear weapons be credible (para 48).

Famously, at paragraphs 67 and 96 of its judgment, the ICJ declined to pronounce on the policy of nuclear deterrence. The Court nevertheless noted that a number of States adhered to the practice during the Cold War and continued to do so, the practice was still strong, and an appreciable section of the international community had been adhering to the policy for many years.

Concluding Thoughts

On the basis of what little is in the public domain at the time of writing, the following seems to be the situation.

1. The U.S. intelligence community has detected a wish in Russia to deploy one or more nuclear weapons into outer space.

2. The use of the word “put” in the media reports implies that Russia’s “wish” might be to station one or more nuclear weapons in outer space, potentially in Earth orbit.

3. There has, as yet, been no use of the wished-for capability, so the question of an unlawful use of force, and the related question of a possible armed attack by the same means, simply do not arise.

4. The Kremlin has now reportedly dismissed the U.S. warning about Russian nuclear weapons in space, describing this as a “malicious fabrication,” so the question of a threat communicated by words also does not arise.

5. If the Russian government were to deploy such weapons into outer space and if it made statements threatening to use the weapon against a satellite belonging to a particular State, this would be an unlawful threat to use force contrary to Article 2(4) of the UN Charter.

6. If the Russian government were to place such weapons in orbit and then acted in a manner that clearly implied that the weapons would be used against a specified State, this would also potentially amount to an unlawful threat of force contrary to Article 2(4). The word potentially is used here because much will depend on the specificity of the threat.

7. If the Russian government were to place nuclear weapons of any description in Earth orbit, or on a celestial body, or if it were otherwise to station such weapons in outer space, it would be in breach of Article IV of the Outer Space Treaty of 1967. This is a treaty of which Russia is a joint depository and to which it is a State party. It has not, however, done so as yet, so far as is known.


Air Commodore William H. Boothby retired as Deputy Director of Royal Air Force Legal Services in July 2011. He is Honorary Professor at the Australian National University and also teaches at the University of Southern Denmark and at the Geneva Centre for Security Policy.



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