Monumental progress has been made in the exploration of outer space since the launch of Sputnik 1, the first manmade satellite, over six decades ago (NASA | History – Sputnik 2011). This rapid advancement in technology and activities related to outer space necessitates the parallel development of regulatory laws (Zhao & Jiang 2019). Indeed, despite outer space not being subject to national sovereignty and jurisdiction, the absence of comprehensive legal frameworks could lead to regulatory vacuums. This gap in governance has become increasingly relevant, especially since the Reagan Administration’s “Star Wars” initiative in the 1980s, which shifted the notion of space-based military conflicts from theoretical discussions to realistic possibilities (Handley 2023).
Reflecting these advancements and concerns, space has evolved into a critical arena for national defense and strategic interests. This evolution is evident in NATO’s designation of space as the fifth operational domain, alongside land, water, air, and cyberspace (Space Militarization | How Does Law Protect in War? – Online Casebook, n.d.). Further emphasizing this shift, the establishment of the United States Space Force (USSF) as a new branch within the US Armed Forces symbolizes a growing trend among nations towards the militarization of space, igniting debates about the implications and legalities of such militarization.
As humanity extends its reach into the cosmos, the once peaceful realm of outer space increasingly becomes an arena for strategic competition and potential conflict. The militarization and weaponization of space mark a significant shift in how nations perceive and utilize this new frontier. This shift presents unique challenges to International Humanitarian Law (IHL), a body of law traditionally applied to terrestrial warfare. Principles of IHL, such as distinction, proportionality, and prevention of unnecessary suffering, are now being tested in the context of space, an environment vastly different from Earth’s battlefields. This essay addresses the pivotal question of how IHL can be extended and adapted to the complex, multi-dimensional landscape of space warfare.
Current Legal Framework
The origin of the Outer Space Treaty is anchored in the discussions of the Legal Subcommittee in 1966. This led to the United Nations General Assembly adopting resolution 2222 (XXI) that same year. This resolution was an extension of the principles laid out in the Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space, which itself was established by the General Assembly resolution 1962 (XVIII) in 1963. (Robert Wickramatunga, n.d.).
The International Committee of the Red Cross (ICRC) has significantly influenced the discourse on space law, aligning with its humanitarian objectives. Their involvement is particularly notable in shaping the UN General Assembly Resolution. This resolution focuses on curbing space-related threats by developing a framework of norms, rules, and principles for responsible conduct in outer space. Furthermore, the ICRC’s engagement with the General Assembly Resolution on preventing an arms race in outer space underscores its dedication to applying humanitarian values in this emerging arena.
In line with the principles of IHL, the Treaty and the ICRC’s Customary IHL Study (Rules 70-84) prohibit the use of weapons that are indiscriminate or cause superfluous injury or unnecessary suffering (ICRC, n.d.). These prohibitions are not confined to terrestrial warfare but extend to space activities as well. Moreover, the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques, through Articles I and II, expressly prohibits the military or hostile use of environmental modification techniques. These include any method of altering natural processes to affect the dynamics of Earth or outer space, especially if these modifications have widespread, long-lasting, or severe impact.
From Land Mines to Space Mines
The Outer Space Treaty lays a thorough legal foundation for activities in outer space. This framework is further refined by the International Committee of the Red Cross (ICRC), which emphasizes the importance of conducting space activities responsibly. Their combined efforts highlight the critical need for ethical and accountable actions in this expansive domain. However, the actual application and enforcement of these principles in real-world scenarios present a distinct set of challenges. This is particularly evident when examining specific incidents that test the limits and interpretations of the established legal norms. In a groundbreaking move in 2007, China successfully tested a direct-ascent Anti-Satellite (ASAT) missile by targeting and destroying one of its obsolete weather satellites (Stephens & Steer 2015). This event was not only a display of China’s advanced space capabilities but also a stark demonstration of the consequences of employing such weaponry. In their detailed analysis of the ASAT, Nicholas L. Johnson from NASA Johnson Space Center, along with his colleagues E. Stansbery, J.-C. Liou, M. Horstman, C. Stokely, and D. Whitlock, provides a comprehensive examination of the event’s characteristics and consequences. They stated the missile strike generated an extensive debris field, scattering over two million fragments, each as large as 10 cm. These fragments, orbiting at speeds from 3,000 to 7,600 meters per second (or about 27,000 kilometers per hour), pose a significant risk to space operations. To illustrate, these speeds dwarf that of a 5.56mm bullet from a standard military rifle, which travels at 940 meters per second. The 2007 ASAT missile test by China, while showcasing advanced capabilities, also highlighted the legal ambiguities in the Outer Space Treaty concerning active space weaponry.
The incident brought to light the potential for a dangerous escalation in space debris, known as the Kessler Syndrome, where one collision begets more, leading to a self-perpetuating cycle of space debris creation (Riley 2023).
Furthermore, the testing and deployment of co-orbital ASAT weapons compound these dangers. These rocket-launched devices are designed to enter the same orbital path as their target and can be navigated within orbit to approach and eventually destroy it Stephens & Steer 2015). The catastrophic 2009 collision between the inactive Soviet-era Cosmos 2251 satellite and an active Iridium communications satellite illustrates the extensive destructive potential of co-orbital ASATs (Iannotta 2009). This incident resulted in more widespread destruction than the debris field created by China’s 2007 ASAT missile test, underscoring the severe risks associated with these kinds of space weapons.
The employment of ASAT weapons in space, an escalation in contemporary military strategies, not only introduces numerous humanitarian concerns but it also poses a challenge in the face of the principles of International Humanitarian Law (IHL) (Stephens & Steer 2015). The capability of ASATs to disrupt, damage, or even destroy satellites used for civilian and dual purposes (both civilian and military) brings into focus the far-reaching implications of such military actions in space.
Central to the concerns raised by the deployment of ASAT weapons is the creation of space debris. As I discussed before, when ASATs are used to destroy space objects, they generate extensive debris fields. This debris, which can remain in orbit for years, poses a persistent threat to vital civilian satellites that are crucial for communication and weather forecasting and also to the International Space Station (ISS). This outcome is particularly problematic from an IHL perspective, as it leads to indiscriminate effects that are uncontrollable once initiated. Such actions directly breached the principle of distinction, a cornerstone of IHL, which mandates a clear differentiation between civilian and military objectives.
Moreover, the impairment of weather satellites through ASAT activities has direct and detrimental effects on disaster management and civilian protection. IHL places a high premium on the safeguarding of civilians, particularly during conflicts. The disruption of critical services like weather forecasting, which is essential for predicting and managing natural disasters, can be interpreted as a violation of IHL’s principle of civilian protection. Similarly, the interruption of satellite communications, pivotal for humanitarian assistance during emergencies, further challenges the principle of humanitarian relief as enshrined in IHL.
Another aspect of concern is the existence of astronauts in space, widely regarded as civilians under IHL, who also face increased risks due to the potential for collisions with space debris resulting from ASAT use. This not only endangers their lives but also violates the principle of civilian protection. IHL’s specific treatment of astronauts as envoys of mankind highlights the obligation to ensure their safety, underscoring a broader commitment to humanitarian principles in the domain of space.
Future Challenges and Limitations
In the realm of space law, the limitations of International Humanitarian Law (IHL) and the Outer Space Treaty (OST) in regulating weapons in space present significant challenges. These limitations reflect the complexity and evolving nature of space activities and the need for a nuanced legal framework.
In 50 years of existence, OST has managed to establish legal frameworks for peacekeeping in outer space. However, since its inception, OST witnessed technological and military advances such as the privatization of space exploration, dangers of the excessive satellite debris and the weaponization and militarization of space which pose a challenge and limitation.
In conclusion, the escalating militarization and weaponization of space underscore the urgent need for robust legal frameworks to manage these developments. The limitations of the OST and IHL in this context are increasingly apparent. While the OST laid a foundational framework for peace in space, its vague definitions and lack of comprehensive rules on the weaponization of space have led to regulatory gaps. This is exacerbated by the OST’s inability to enforce its provisions effectively due to the absence of a dedicated space law enforcement body.
The duality of space technologies and the rapid pace of technological advancements further complicate the application of IHL, which struggles to adapt its principles to the distinctive challenges of space warfare. These principles, designed for terrestrial conflicts, face interpretative challenges when applied to the outer space. As nations continue to prioritize military interests in space, there is a growing necessity to develop new treaties and legal mechanisms that can keep pace with technological advancements and ensure the peaceful use of outer space. The future of space governance hinges on the international community’s ability to address these challenges and limitations, ensuring that space remains a domain for peaceful exploration and cooperation.
 See, ICRC, Study on Customary International Humanitarian Law, 2005, Rules 7–11, 14, 15.
 See, Article 54, ICRC Customary IHL Study; Article 54, Additional Protocol I; Article 14, Additional Protocol II.
 Working paper titled “Humanitarian Implications and Limitations Imposed by International Humanitarian Law (IHL) on the Possible Deployment of Weapons in Outer Space” is a working paper presented by the International Committee of the Red Cross (ICRC). This paper was submitted to the Group of Governmental Experts, who are focused on developing additional practical measures to prevent an arms race in outer space.
 Outer Space Treaty, Art. V and Rescue of Astronauts Agreement, Arts I-IV.