Russia’s unannounced direct-ascent anti-satellite (DA-ASAT) missile test last Monday raises important legal and policy questions about the prohibition on the use of force in outer space. The highly destructive weapons test – which forced astronauts aboard the International Space Station to seek shelter and created a long-lasting field of space debris – underscores the need to urgently develop international standards for responsible behavior in space.

The timing of the test is provocative, as the United Nations (UN) General Assembly’s First Committee (Disarmament and International Security) passed several draft resolutions at the start of this month aimed at preventing an arms race in outer space, which are expected to be adopted at the next General Assembly session in early December. China and Russia were among only a handful of states to vote against the key draft resolution on “Reducing space threats through norms, rules and principles of responsible behaviours,” reflecting a deep rift on this issue between the major space powers.

Passing these reforms is crucial given the long-term consequences of resorting to force in space. Russia’s missile strike against its own defunct satellite, Tselina-D, created a field of space debris of nearly 1,500 trackable pieces (i.e., pieces greater than about 10 cm in diameter). Given high orbital velocities, even tiny pieces of space debris place astronauts and satellites at risk and, in the worst case, could lead to Kessler Syndrome – a cascading cloud of orbital debris – preventing access to outer space from Earth for generations.

This is not the first kinetic DA-ASAT test creating a long-lasting debris field: notoriously, China conducted such a test in 2007, blowing up its own weather satellite and creating 2,300 pieces of debris. The United States also conducted a kinetic DA-ASAT test in 2008, creating 400 pieces of debris, as did India in 2019, creating similar levels of debris. (The United States at the time justified the low-altitude strike against its malfunctioning spy satellite as necessary to prevent its re-entry into the atmosphere and the release of toxic fuel.)

The Russian defense minister, Sergei Shoigu, hailed Monday’s test as “promising” and denied that the fragments posed any threat to space activity. The United States retorted with a statement by Secretary of State Anthony Blinken: “The long-lived debris created by this dangerous and irresponsible test will now threaten satellites and other space objects that are vital to all nations’ security, economic, and scientific interests for decades to come.” The United Kingdom and France also condemned the weapons test, with the French Ministers for Europe and Foreign Affairs and for the Armed Forces labelling it “a destabilizing, irresponsible action which could cause very long-term consequences for the space environment and all space players.”

The Russian DA-ASAT test takes place against the background of ongoing and urgent efforts by the international community to prevent an arms race in outer space, known as “PAROS.” PAROS seeks to preserve outer space as a peaceful domain for the benefit of all, by preventing the weaponization of outer space, reducing threats to space systems, and avoiding escalated tensions and conflict caused by misunderstanding and miscommunication. Efforts towards PAROS began in earnest shortly after the conclusion of the last space treaty, the Moon Agreement, in 1979, with negotiations taking place in various multilateral fora, including the Conference on Disarmament, the UN Committee on the Peaceful Uses of Outer Space, and the UN General Assembly First Committee.

However, efforts to negotiate PAROS have been long stymied due to a deep divide in the international community on the best approach to ensuring space neutrality. The approach favored by Russia and China is a binding treaty, namely, the “Treaty on the Prevention of the Placement of Weapons in Outer Space, the Threat or Use of Force Against Outer Space Objects” (PPWT) proposed in 2008 and revised in 2014. An alternative approach would be to adopt soft law guidelines aimed at transparency and confidence building measures (TCBMs), such as the European Union’s Draft International Code of Conduct for Outer Space Activities. Key substantive issues at stake include effective verifiability, legal gaps in definitions and framing of rules which could be exploited by adversaries (for example, Russia’s DA-ASAT test would not violate the Russia-China draft treaty, which does not ban ground-based weapons), and the desire for flexibility.

A breakthrough finally was reached on Nov. 1 this year, when the UN General Assembly First Committee adopted a UK-proposed draft resolution to establish an Open-Ended Working Group (OEWG) to identify threatening and irresponsible space behaviors. This resolution is likely to be approved by the UN General Assembly next month, given the voting patterns in the First Committee, in which 163 States voted in favor, with nine abstaining and only eight against (including China and Russia). The OEWG will meet in 2022 and 2023 to:

(a) Take stock of the existing international legal and other normative frameworks concerning threats arising from State behaviors with respect to outer space;

(b) Consider current and future threats by States to space systems, and actions, activities and omissions that could be considered irresponsible; [and]

(c) Make recommendations on possible norms, rules and principles of responsible behaviours relating to threats by States to space systems, including, as appropriate, how they would contribute to the negotiation of legally binding instruments, including on the prevention of an arms race in outer space.

In parallel with these multilateral initiatives, private efforts to codify the applicability of international law to military uses of outer space such as the Manual on the International Law Applicable to Military Uses of Outer Space (MILAMOS) and the Woomera Manual are also underway. In the face of relatively slow progress in confronting these urgent threats through UN channels, the Outer Space Institute (a global network of space experts) recently launched an International Open Letter on Kinetic Anti-Satellite Testing that has already gathered hundreds of prominent signatories, calling for a new international treaty banning kinetic DA-ASAT weapons testing of the type we have just witnessed by Russia. (The letter is open for further signatures here.)

Needless to say, there is already an international legal framework that applies to military activities in outer space, including the Outer Space Treaty, the UN Charter (especially its article 2(4) prohibiting the use of force between States), international humanitarian law, and international human rights law. But there are major areas of ambiguity that will need to be addressed, including the controversial questions of what counts as a “space weapon” and “use of force” in outer space. The unique environment in outer space gives rise to special challenges of identifying prohibited “uses of force,” including issues of attribution, dual-use objects of a military and civilian nature, difficulties with identifying hostile intent (for instance, when a satellite conducts rendezvous and proximity operations), and whether attacks with temporary and reversible effects (such as dazzling satellites through directed energy attacks, i.e., temporarily blinding an imaging satellite by using a laser to interfere with its sensor) would meet the threshold of prohibited force under jus ad bellum. Of particular relevance to Monday’s weapons test, a DA-ASAT strike against a state’s own satellite could in certain circumstances fall within the scope of prohibited force under article 2(4) of the UN Charter, since the space debris generated could cause foreseeable damage to another State’s space object. Yet none of the international efforts to define “use of force” in outer space have achieved consensus so far. And importantly, under current international law, kinetic DA-ASAT tests are not explicitly banned.

The use of force in space would also have significant non-military implications. Critical civilian infrastructure increasingly relies on space systems, including infrastructure essential for food production, health care, disaster relief, transport, communication, energy and trade, and the global navigation satellite systems such as GPS, which themselves underpin global communication networks, banking and financial markets, and energy grids. Disabling, damaging, or destroying such satellites, including through missile attacks, could have “wide-reaching consequences for civilians on earth.”

Russia’s missile test and the long-lasting space debris field it created should give policymakers increased impetus to clarify the international legal rules and norms applicable to military uses of outer space in order to prevent conflict and preserve this domain for peaceful purposes.

Image: Satellite on planet background – 3d rendered image. Credit: koto_feja