Russia’s destructive ASAT test in November 2021 capped off a difficult year for the due regard principle in space. Codified in Article IX of the 1967 Outer Space Treaty (OST), the due regard principle obligates States to conduct all their space activities “with due regard to the corresponding interests of other all other States Parties to the Treaty.” In theory, a State could breach this obligation, and the breach would constitute an internationally wrongful act. Under the international law of State Responsibility, affected States can respond to an internationally wrongful act with lawful countermeasures, among other forms of recourse. Due regard, then, is (at least, theoretically) an enforceable international legal obligation in space. Brian Chow and Brandon Kelly recognize this when they suggest the United States could, in some circumstances, “push for the use of lawful countermeasures to enforce international obligations such as the Outer Space Treaty’s Article IX requirement of ‘due regard.’”

In practice, however, States have not been invoking Article IX’s due regard principle as an enforceable international obligation that imposes legal constraints on space activities. As Hitoshi Nasu and Michael Schmitt observed in 2020, “[e]xactly what due regard requires of States conducting space activities is unclear.” (They suggest analogizing to “an equivalent” due regard principle in maritime law.) With no clear meaning, it is difficult to determine when due regard is breached as a practical matter, and if it is unclear when a breach has occurred, then enforcement becomes nearly impossible. Indeed, little to no State practice exists of States asserting a breach of the due regard obligation in space. Even if a State were to assert a breach, there is no precedent for resolving such a dispute. Article IX has historically been thought of more as a toothless consultation requirement or as a provision addressing harmful contamination of the environment than as the source of a distinct obligation to act with due regard in the conduct of all space activities.

In the maritime domain, unlike in the space domain, the due regard principle is invoked as an enforceable international legal obligation. Several provisions in the United Nations Convention on the Law of the Sea (UNCLOS), like Articles 56(2), 58(3), and 87, obligate States to exercise their rights at sea with due regard to the rights of others. Another provision, Article 287, provides options for settling disputes (a feature lacking in the OST). The Permanent Court of Arbitration, in the Chagos Island Arbitration (2015) between the United Kingdom and Mauritius, has ruled the due regard obligation does not create a universal rule of conduct but it does call for States to have such regard for the rights of other States as called for by the circumstances and by the nature of the rights in question (para 519). After weighing those factors, the Tribunal in Chagos found the United Kingdom to have breached its due regard obligation (para 536).

Although the due regard principle has not yet been invoked as a legal rule in space, this could change. Treaty interpretations can evolve to adapt to new situations. This is particularly true of provisions in the OST, which was intended to evolve. Manfred Lachs, the famed international law expert and International Court of Justice judge who presided over the negotiations of the OST, later wrote that some of the treaty’s principles may have been “couched in very general and broad terms” but the need for “more detailed specification of them or their corresponding obligations” will “grow in confrontation with practice, while adequate interpretation will be called for in concrete situations.”

Brian Egan, then the U.S. State Department legal advisor, echoed this sentiment in 2016. In celebrating the fiftieth anniversary of the Outer Space Treaty, he said, “the open-textured formulation of the Treaty’s basic principles … will allow the legal framework to evolve over time in light of changing circumstances and capabilities.” More recently, Nasu and Schmitt recognized the potential of the due regard principle in Article IX to take on a functional meaning. They wrote, “[s]ubsequent State practice, including verbal practice such as the issuance of warnings, will hopefully contribute interpretive clarity as to the due regard expected of spacefaring nations when conducting weapons testing.”

Is due regard on the cusp of an interpretive evolution?

If subsequent State practice can shape the due regard principle in Article IX into something it has never been before – a useful, enforceable legal obligation – then is due regard on the cusp of an interpretive evolution? Developments in 2021 suggest otherwise.

The difficulties began in May 2021, when the United States issued its National Submission pursuant to UN General Assembly Resolution 75/36 on the subject of reducing space threats through norms of responsible behavior. The U.S. submission urged States to think about what it means to “operate national security spacecraft with due regard to others and in a professional manner.” This suggestion was one of five recommended discussion “starting points” toward developing more specific voluntary norms. The U.S. submission was careful to assure that these norms would “compliment” existing international law and that “the subject of these discussions do not replace or alter States’ obligations or rights under international law.”

The U.S. submission places a spotlight on due regard as a voluntary norm while diminishing it as a legal obligation. The submission detracts from the legal nature of the due regard principle by pairing it with a non-legal duty to operate “in a professional manner.” It could also be read to suggest that due regard is a non-binding norm in addition to, and distinct from, the binding legal obligation that, confusingly, shares the same name.

Adding to this confusion is the assertion that discussions about due regard would not affect existing legal obligations. Ordinarily, States’ discussions of the meaning of treaty principles can be considered a form of State practice that can influence treaty interpretation. If States’ discussions on the meaning of a principle codified in Article IX are somehow not considered as developments in treaty interpretation, then the due regard principle will have been divorced from its legal underpinnings. Whatever the due regard principle might gain in specificity under the proposed discussions, it will lose in legal status.

The difficulties for the due regard obligation continued when, in July, the Department of Defense (DoD) issued its five tenets of responsible behavior in space. Most of the tenets closely resemble the five starting points offered in the U.S. submission to UN Resolution 75/36, including the first tenet: “operate in, from, to, and through space with due regard to others and in a professional manner.” Like the U.S. submission to the UN, this DoD tenet champions due regard as a norm of responsible behavior while simultaneously diminishing its value as a legal obligation. Due regard is once again conflated with a voluntary norm to operate “in a professional manner.” In addition, DoD components are expected to adhere to each tenet “unless otherwise directed,” further reinforcing the perception that due regard is not actually a legal obligation. Any specific behaviors associated with the first tenet will be regarded as non-legally binding, raising difficult questions about what behaviors, if any, might be associated with the legally binding due regard obligation in Article IX.

A Missed opportunity to develop State practice

The latest setback came in the aftermath of Russia’s destructive anti-satellite (ASAT) test. On Nov. 15, 2021, Russia destroyed one of its own satellites with a missile, reportedly generating more than 1,500 pieces of trackable debris that will put other satellites in low Earth orbit (LEO) at risk for five years or more. The intentional creation of long-lasting debris in a crowded orbit presented the perfect opportunity for States to question whether such behavior is lawful or, instead, a possible breach of Article IX’s due regard principle.

In the past, destructive ASAT tests and operations have not prompted legal objections based on the due regard principle. The United States destroyed a satellite in 1985 and again in 2008, China destroyed a satellite in 2007, and India destroyed a satellite in 2019. Apart from Japan’s vague legal objection to China’s 2007 test, States have established a trend of condemning the intentional creation of long-lasting debris while remaining silent about the legality of such tests under the OST.

The international response to Russia’s test continues this trend. Japan called the test irresponsible, as did Germany. Australia called it provocative. South Korea’s foreign ministry reportedly expressed concern. The U.S. called the test reckless and irresponsible. France’s Defense Minister tweeted that the “space raiders” have an “overwhelming responsibility in generating debris.” The European Union called the test irresponsible and contrary to the principles reflected in the UN Space Debris Mitigation Guidelines. The United Kingdom’s Defence Secretary tweeted his condemnation. Conspicuously absent from international government responses is any suggestion that Russia’s test may have been conducted with a lack of due regard, in violation of the legal obligation codified in Article IX.

As the Russia experience shows, States continue to be silent on the legality of destructive ASAT tests, no matter how egregious. This could be a conscious decision by States that are not keen to give teeth to Article IX, or it could simply be a missed opportunity. Either way, the silence of States suggests that the due regard principle is further from, not closer to, achieving interpretive clarity.

In the aftermath of the Russian test, the due regard obligation has become even more deeply entrenched as a vague legal principle with questionable utility and, evidently, no application to the intentional creation of long-lasting debris. The Russian test placed astronauts in direct danger and “put the thousands of satellites currently in orbit today at severe risk of becoming victim of the Kessler syndrome.” If this is not enough for States to start asserting the relevance of Article IX’s due regard obligation, then it is fair to ask if States are, in effect, asserting its irrelevance.

Time for States to take positions interpreting due regard

What is lost if the events of 2021 have pushed the due regard principle further into irrelevance? Time, potentially. A new UN open-ended working group may soon begin a years-long process of developing recommendations for norms of responsible behavior in space. These recommendations could then be considered as a basis for an international treaty, a process that would likely take several more years with no guarantee of success. By contrast, the due regard principle is already binding law. It could become a functional rule, but only if States take the first step of simply saying what they think it means and when it applies. These interpretations would not be authoritative at the outset, but they could grow in acceptance over time, especially with efforts among States to coordinate interpretations.

A similar evolutive process is underway involving other legal principles in space and in cyberspace. In space, numerous State space agencies have signed on to NASA’s Artemis Accords, reflecting an increasing acceptance of an interpretation of OST Article II – the non-appropriation principle – that would permit the recovery and exploitation of space resources. In cyberspace, numerous States are taking positions on whether sovereignty applies in cyberspace as a rule that can be breached in its own right, or instead, as a mere principle that cannot be breached but from which other legal obligations are derived. If States achieve their desired outcomes in either instance, then they will have done so without the additional time burden of negotiating new international treaties. The same could be true for the due regard principle in space, but after 2021 this is becoming increasingly unlikely.

Although the due regard principle did not fare well in 2021, the setbacks serve as a useful reminder that norm development and treaty interpretation do not follow the same process. Norm development may eventually result in law, whereas treaty interpretation takes the law as a starting point. The due regard principle is already codified in space law. States, though their practice, can interpret its meaning, and these meanings may become widely accepted over time. Accordingly, understanding what due regard means in space is less a matter of developing a due regard norm in a working group, and more a matter of establishing State practice in the interpretation of a Treaty and achieving widespread acceptance of that interpretation.

This process can start now, if States so desire. States do not need to wait before taking positions on how they interpret the application of international laws that already exist. In 2022 and beyond, States can continue to focus on making new rules in space, but these efforts do not have to come at the expense of interpreting the existing rules.