Shadows in Orbit: Unpacking the Cosmos 2588 Amidst Legal Uncertainty in Space

On 23 May, 2025, Russia launched Cosmos 2588, the latest in its Cosmos series of military satellites, into low Earth orbit (LEO). As first reported by independent satellite tracker Bart Hendrickx on the NASA SpaceFlight Forum, its orbital plane lies very close to that of a U.S. government reconnaissance satellite, USA 338.

Marco Langbroek, a Dutch astronomer, has noted that the launch of Cosmos 2588 marks the fourth time in five years that a Russian military satellite has been placed in close orbital proximity to a U.S. military optical reconnaissance satellite. While the first case (Cosmos 2542/2543 in the orbital plane of USA 245) may have been an “inspector mission,” he argues that the more recent examples—including Cosmos 2588—likely represent a counterspace capability such as a o-orbital anti-satellite (ASAT) weapon. Slingshot Aerospace, a U.S. satellite tracking company, shared an orbital image of Cosmos 2588 on LinkedIn. The company noted that although Cosmos 2588 is classified as an inspection satellite, it is believed to be equipped with a kinetic weapon capability, a belief reinforced by the absence of official disclosure regarding its mission or behaviour

The recent launch of Cosmos 2588 has revived long-standing concerns about the potential deployment of ASAT capabilities and the broader issue of space weaponization. This post explores the legal ambiguity surrounding ASAT technologies and raises the pressing question whether existing legal norms are sufficient to address the growing complexity of military activities in outer space.

Anti-Satellite Weapons and the Outer Space Treaty

A growing number of States are actively developing, testing, and deploying anti-satellite weapons, both kinetic and non-kinetic. High profile demonstrations, such as China’s 2007 and Russia’s 2021 direct-ascent tests, have drawn serious international criticism due to the creation of space debris and their implications for the weaponization of outer space.

ASAT weapons generally fall into two categories:

– Co-Orbital ASATs: These are satellites placed into orbit that manoeuvre near a target to disable or destroy it in proximity, often using kinetic, mechanical, or electromagnetic means.

– Direct-Ascent ASATs: Launched from Earth, these missiles are designed to strike satellites in orbit directly from the Earth.

While the 1967 Outer Space Treaty (OST) remains the cornerstone instrument of space law, it leaves critical legal gaps when confronted with today’s emerging counterspace capabilities. Article IV of the OST explicitly prohibits the placement of nuclear weapons or weapons of mass destruction in orbit around the Earth. But it remains silent on conventional weapons, creating a significant loophole when considering the legality of deployment of ASAT weapons.

This legal ambiguity is compounded by the increasingly dual-use nature of space technologies, where satellites designed for civilian or passive military functions also have inherent destructive potential, thereby blurring the boundary between peaceful use and potential threat. As such, determining what constitutes a “peaceful” military presence in orbit is no longer straightforward.

The case of Cosmos 2588 underscores these gaps. If it does, in fact, possess kinetic ASAT capabilities, then its behaviour represents not just a technical challenge but a legal one, testing the limits of what the OST allows under the principle of “peaceful purposes.”

The Relevance of Article IX of the Outer Space Treaty

While legal commentators focus on Article IV of the OST, Article IX plays a vital role in regulating behaviour in orbit. It provides three interrelated legal obligations that bear directly on the deployment of ASAT capabilities.

1. Due regard obligation: States shall conduct activities in outer space with “due regard” for the interests of other parties to the treaty. In the context of co-orbital ASAT systems, this implies a responsibility to avoid actions—such as close orbital manoeuvres—that could endanger or destabilize another State’s space assets.

2. Duty to avoid harmful contamination: Article IX also requires that space activities be carried out in a manner that prevents potentially harmful contamination. This obligation reflects environmental concerns and aims to preserve the scientific integrity of outer space.

3. Consultation mechanism: When a State’s planned activity is reasonably expected to cause harmful interference with activities of other State parties, it must undertake prior international consultations with affected States.

Crucially, the OST does not define key terms such as “due regard” or “harmful interference,” leaving significant room for interpretation. States have, for the most part, refrained from articulating clear interpretations or positions on the scope and application of these obligations, further compounding the ambiguity. Nonetheless, the spirit of Article IX suggests that behaviour such as co-orbital shadowing— especially if combined with suspected kinetic capability— may run counter to the treaty’s intent.

If Cosmos 2588 is indeed manoeuvring in close proximity to U.S. military satellite without notification, and with potential for physical interference, it arguably violates both the “due regard” obligation and the duty to consult, as articulated in Article IX of the OST.

Defining “Peaceful Purposes”: Between Principle and Practice

The case of Cosmos 2588, particularly its close co-orbital manoeuvring near a U.S. military satellite without prior consultation, raises a deeper legal issue. Namely, what exactly constitutes a “peaceful” activity in outer space?

The use of outer space for “peaceful purposes” has been a cornerstone principle of space law since the dawn of the space age. Despite its centrality, the meaning of the term of “peaceful” is not defined in the Outer Space Treaty, to which both Russia and the United States are parties.

In this respect, two primary interpretations have emerged over time.

1. The non-militarization doctrine: This view advocates for a complete prohibition on any military activities in outer space.

2. The non-aggression doctrine: More commonly accepted in State practice, this interpretation allows for military uses of outer space so long as they do not involve the threat or use of force, as outlined in Article 2(4) of the UN Charter.

Over time, State practice strongly indicates that the notion of “peaceful purposes” cannot be interpreted to exclude all military activities. To date, passive military uses such as surveillance, reconnaissance, early warning systems, and satellite navigation have become routine and widely accepted. These functions, while military in nature, are generally not seen as violating the peaceful purposes principle.

However, Cosmos 2588 complicates this framework. Unlike passive systems, it shows manoeuvrability, co-orbital positioning, and suspected kinetic capabilities. Thus, Cosmos 2588 serves as a practical test case for the boundaries of the non-aggression doctrine. Can a space system that does not attack but appears to prepare for offensive action still be considered “peaceful”? Yet, the deliberate proximity of systems like Cosmos 2588 to U.S. satellites raises pressing questions about when such positioning crosses the threshold into a prohibited threat—a question explored in the following section.

“Threat to Use Force” in Outer Space: Applying Article 2(4)

The blurred distinction between peaceful and hostile space activities—as illustrated by Cosmos 2588— leads naturally to a critical legal question. At what point does a satellite’s behaviour constitute a “threat to use force” under international law?

This question is addressed by Article 2(4) of the UN Charter which states, “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.”

Article 2(4) applies to any activity in the exploration and use of outer space, including the Moon and other celestial bodies, in accordance with Article III of the OST. This provision mandates that all space activities be carried out in accordance with international law and the UN Charter. As such, the “peaceful purposes” principle must be interpreted in light of Article 2(4) of the UN Charter.

In the 1996 Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, the International Court of Justice emphasized that a threat to use force is unlawful if the actual use of force would itself be unlawful. Similarly, as highlighted in the Woomera Manual on the International Law of Military Space Operations—a non-binding but authoritative guide developed by legal experts—a threat to force is not defined by capability alone. Rather, it requires conduct that, in context, signals an intention to unlawfully use force. This includes factors like proximity, timing, and geopolitical tension.

In the case of Cosmos 2588, although no force has been used, the satellite’s close co-orbital positioning near a U.S. military asset—combined with its manoeuvrability and suspected kinetic capability—may be seen as a calculated display of force readiness. Moreover, the broader context matters. The long-standing strategic rivalry between the United States and Russia, rooted in Cold War mistrust and increasingly manifesting in orbital manoeuvring, strengthens the perception that these behaviours are not benign.

Legal Certainty in Orbit: Future of Space Governance

As Cosmos 2588 illustrates, the legal frameworks governing space have not kept pace with the speed and complexity of counterspace technologies. Despite international efforts to maintain outer space for peaceful purposes, the rapid evolution of space technology and the growing dependence on satellites for both military and civilian applications have positioned outer space as a critical arena for strategic competition among nations.

The absence of clear and binding legal restrictions against peacetime deployment of counterspace technologies—particularly ASAT weapons—poses a vital challenge to maintain international peace and security. Given this legal ambiguity, while binding treaty regulations remain essential for ensuring predictability and legal stability in orbit, the pace of technological innovation—coupled with geopolitical tensions—makes comprehensive legal regulation increasingly difficult.

The Role of Soft Law

In this sense, soft law instruments can be adopted as a practical alternative to new treaties without limiting the development of emerging space technologies.

A range of non-binding initiatives has emerged in recent years to promote responsible conduct in space and mitigate the risks posed by ASAT technologies. These include:

– The 2013 UN Group of Governmental Experts recommendations on Transparency and Confidence-Building Measures;

– The European Union’s International Code of Conduct for Outer Space Activities;

– The Russia-China proposed Treaty on the Prevention of the Placement of Weapons in Outer Space, which notably does not prohibit ground-based ASAT weapons; and

– The work of the ongoing Open-Ended Working Group on the prevention of an arms race in outer space, operating under the auspices of the UN General Assembly.

Although these instruments lack binding legal authority, soft law instruments help bridge regulatory gaps and foster mutual understanding, specifically with dual-use technologies. Over time, soft law norms—if widely accepted and consistently applied—can evolve into customary international law and binding legal obligations through incorporation into national legislation.

Conclusion

The growing militarization of outer space, as illustrated by the case of Cosmos 2588, demonstrates the widening gap between technological capabilities in space and the legal frameworks meant to regulate them. Its behaviour—marked by close proximity to a U.S. military satellite, suspected kinetic capabilities, and a lack of transparency—exposes how current regulatory frameworks under the OST struggle to address the realities of modern counterspace operations. Key legal principles such as “peaceful purposes,” “due-regard,” and “threat of force” remain vague and open to conflicting interpretation, especially when applied to dual-use, manoeuvrable satellites.

In the absence of progress on binding legal instruments, soft law initiatives stand as the most useful tools for shaping responsible conduct in space. Still, their success depends entirely on political will and consistent State practice. Ultimately, Cosmos 2588 reminds us that space security is no longer a theoretical issue. The legal certainty in orbit will require more than aspirational principles, before today’s grey zones become tomorrow’s battlegrounds.

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Berfin Deniz Çabuk is a PhD Candidate in international law at Utrecht University.

The views expressed are those of the author, and do not necessarily reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense. 

Articles of War is a forum for professionals to share opinions and cultivate ideas. Articles of War does not screen articles to fit a particular editorial agenda, nor endorse or advocate material that is published. Authorship does not indicate affiliation with Articles of War, the Lieber Institute, or the United States Military Academy West Point.

 

 

 

 

 

 

Photo credit: Ministry of Defence of the Russian Federation, mil.ru