Challenges to Space Activities in the Context of Mega Satellite Constellations: A Focus on Environmental Impacts

With the advent of small satellite constellations, the risk of collisions with current objects in outer space, LEO in particular, has significantly increased. This raises the possibility of catastrophic scenarios, often referred to as ‘Kessler Syndrome.’ According to National Aeronautics and Space Administration (NASA), LEO may become congested in the future, leading to more accidents and debris falling back to Earth (Kessler et al. 2010). The most remarkable case was when the inactive Cosmos Satellite 2251 collided with Iridium Satellite 33 and triggered panic in the space sector concerning protecting the environment in space (Jakhu 2010). The outer space treaty (OST) places considerable importance on collision prevention rather than intrusion into outer space. It asserts that it is the responsibility of all states to avert such occurrences.

Although this treaty outlines the principles of collaboration, its vague language and lack of specific guidelines make it inadequate for preventing orbital collisions or addressing satellite accidents. In addition, OST does not discriminate between small and mega satellites, and all of its provisions are primarily designed for large satellites and seek to extend the same benefits and obligations to small satellites without accounting for their unique needs (Marboe & Mosteshar 2016). The OST (1967; UN 1966) and the Liability Convention (LC) (1972; Convention on International Liability for Damage Caused by Space Objects 1971), administer the regulation of space objects (Abbas 2024). While composing the OST, there were no legal provisions regarding the deployment and operation of MSCs in any orbit. Both treaties classify satellites as space objects without differentiating between large and small satellites. Instead, they focus on damages resulting from space activities. They created a structure for getting compensation, granting participants who undergo losses to pursue compensation from those who defiant treaty commitments. Article VII of the OST holds each member state legally responsible for any damage sustained during space operations. Article VII of the OST clearly emphasizes that all member states are responsible for any damage suffered during their space activities. Article I of the LC states that the states that launch the satellite or that launch satellites from its territory are accountable. Article II establishes that launching states are liable for every and any damage to space objects.

Moreover, the OST and, particularly its Article VI, imposes the responsibility for the damages incurred during outer space activities on member states. It also extends this responsibility to non-governmental organizations involved in these activities, provided they operate with the consent and authority of their respective governments. As a result, states become liable for the activities of private companies providing services in space from these states. However, the OST does not define “damage” or specify liability limits; instead, Article 1(a) of the LC defines damage to include personal injury, loss of life, property damage—whether to individuals or states—and health-related issues. Some scholars argue that only recoverable damage caused physically by small satellites in space should be emphasized (Christol 1980).

In a recent report to Congress (FAA 2023), the USA Federal Aviation Administration (FAA) expressed concerns regarding the potential dangers posed by SpaceX Starlink satellites when they re-enter the Earth’s atmosphere. The FAA’s concerns specifically relate to the space debris released by these satellites, which poses a risk to individuals on the ground or aircraft in flight. The report, submitted in September 2023, suggested that if current trends continue, by 2035, debris from such re-entries is likely to result in one fatality every two years. Thus, the FAA is addressing the issue of space debris management and the safe deorbiting of defunct satellites with urgency. The FAA report also specified that over 85% of the risk to both ground populations and aviation in 2035 from re-entering debris would be attributed to Starlink satellites. Therefore, Starlink is a major source of risk in the space domain. The FAA report also assessed the potential risks to individuals on the ground and in aircraft associated with the debris released by the unplanned re-entry of satellites positioned in LEO. The report assumes that by 2035, 12 major satellite constellations will achieve full operational status in orbit and will adhere to satellite deorbiting protocols (Schrogl et al. 2018).

In a detailed interaction with the Federal Communication Commission, NASA expressed concerns about Starlink’s development and the potential for increased orbital collisions. The National Telecommunications and Information Administration submitted a five-page document, accompanied by an additional note from the National Science Foundation, on behalf of NASA (2022). A significant increase in the number of satellites that SpaceX intends to launch has drawn attention from NASA, which states that there is an inherent risk of debris-generating collision events owing to the sheer quantity of objects involved in such an increase (Grotch 2022). This assertion reflects deep-seated concerns about the crowding of specific orbital regions owing to SpaceX’s initiative to expand its Starlink constellations. As noted by NASA, Starlink expansion represents a major threat, increasing the likelihood of space debris generation and the frequency of collisions given the increasing number of satellites and the confined nature of their operational altitudes.

Space debris has emerged as a significant global challenge, jeopardizing the sustainability of space activities and necessitating proactive management. In recent years, an increase in collision incidents has contributed to the accumulation of debris, transforming space into a congested environment filled with hazardous materials (Sheer et al. 2023).

Even the smallest particles of space debris pose a substantial threat, as they can travel at speeds of nearly 10 km/s (approximately 6.21 miles/s)—equivalent to ten times the speed of a bullet—resulting in considerable momentum and potential for catastrophic damage. This debris can trigger chain reactions, creating a debris belt around the Earth and exacerbating the risk of collisions with operational satellites (Sheer & Li 2019a). Even tiny fragments can generate significant energy, increasing their potential for destruction and endangering astronauts aboard the International Space Station, as well as other satellites. For instance, OneWeb currently operates a macro-constellation network consisting of approximately 1,000 functional satellites in LEO (Foreman et al. 2017), with plans to double this number in the future. The growing volume of debris poses a serious threat to these operational satellites, particularly given their relatively short lifespan of just three to five years. This short operational period is likely to lead to an even greater accumulation of space debris as small satellite constellations continue to be deployed. The expansion of mega-constellations amplifies the requirement for effective space traffic management. These constellations are formed by launching a dense distribution of assets into orbits, mainly in LEO, which raises the likelihood of collisions, resulting in the generation of space debris (McClintock et al. 2023).

However, it is expected that state laws regarding the disposal of defunct satellites and the relevant launcher upper stages will be implemented. It would be obligatory for each operator to demonstrate a plan for safely deorbiting their satellites towards designated graveyard orbits at the end of their mission. In addition, operators should have an insurance policy in place to bear the burden of rescue costs in case of mission failure (Sheer & Li 2019b).

Sustainable space activities involve the responsible and efficient use of resources while minimizing negative impacts on both Earth and space environments (Durrieu & Nelson 2013). Although space exploration and utilization offer tremendous opportunities, they also present several challenges in terms of sustainability. Some key issues related to sustainable space activities, such as space launches and operations, can have environmental impacts on both Earth and space. Rocket launches produce greenhouse gas emissions, and the disposal of rocket stages can contaminate ecosystems (Sirieys 2022). The placement of satellites in specific orbits can interfere with astronomical observations and hinder scientific research. Sustainable space activities involve minimizing these impacts through cleaner propulsion systems, responsible launch practices, and coordination among stakeholders. Satellite manufacturers and operators should take responsibility for cleaning up space debris. Another challenge in outer-space innovation is balancing this responsibility while advocating international cooperation on issues such as cybersecurity and the growing number of medium-sized satellite constellations (Hassan & Sheer 2024).

Space activities involve numerous countries, organizations, and commercial entities. Sustainable space exploration requires international cooperation to establish common guidelines and frameworks for the responsible and equitable use of space resources, debris mitigation, and environmental protection. Effective governance mechanisms are required to address issues such as space traffic management, resource allocation, and dispute resolution.

As space activities expand, ethical considerations have become increasingly important. These include the preservation of pristine celestial bodies, respect for indigenous rights in space exploration, equitable access to space resources, and the potential militarization of space. Sustainable space activities require addressing these ethical concerns and ensuring responsible and inclusive practices (McClintock 2023).

The United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) describes space sustainability as ensuring the stability and safety of the space environment while keeping space “open for exploration, use, and international cooperation by current and future generations.” The sustainability of outer space is essential for forthcoming access and exploitation. Efforts to harmonize rapid advancements in satellite technology with the principles of space sustainability are crucial to ensure the continued exploration and use of space and its preservation as a shared and equitable resource for all nations and future generations (West 2020).

The proliferation of orbital space debris poses a hazard to both ongoing and future space activities. Starlink aims to enhance global broadband access; however, its extensive network of satellites adds complexity to the orbital environment, increasing the risk of collisions and the creation of additional debris. A safe, secure, and peaceful space environment is essential for ensuring continued access to and use of space-based infrastructure (Höyhtyä 2022). The societal benefits of mega-constellations must be balanced with the need to maintain the sustainability of the space domain. The increasing number of satellites and space missions can affect scientific observation and research. Light pollution from satellites can interfere with astronomical observations and affect both professional and amateur astronomers (Varela-Perez 2023). Preserving space as a platform for scientific research is crucial for sustainable space activities, and efforts should be made to minimize interference with scientific observations.

Addressing these issues requires a multifaceted approach involving technological advancements, policy frameworks, international collaboration, and public engagement. By promoting sustainable practices and responsible behavior in space activities, we can ensure the long-term viability and benefits of space exploration and utilization while minimizing the negative impacts on both the Earth and space environments (Carrio 2022).

The ITU defines harmful interference as any disturbance that impairs the functionality of radio navigation and other critical safety services or significantly interrupts services that comply with radio regulations. According to ITU Article 45, all radio stations must operate in a manner that prevents harmful interference with the radio services or communications of other member states or any entities authorized to operate in accordance with radio regulations. The ITU identifies unauthorized use of transmitting devices and military operations near conflict zones as the leading causes of such interference.

The integral role of space in supporting the economic, commercial, and military interests of technologically advanced nations makes harmful interference a considerable threat to satellite operations. This risk is further compounded in the context of LEO satellites, which are primarily used for communication and are central to national security (ITU 2020). The escalating reliance on these satellites increases the chances of contested space scenarios, intensifying their vulnerability to harmful interference. Moreover, the advent of mega-constellations and the growing involvement of private satellite ventures introduce additional complexities to national security considerations.

Competition for access to the radio spectrum is increasing. The ITU plays a crucial role in assigning frequencies to communication satellites. However, satellite companies do not directly interact with the ITU or participate in these agreements. Instead, they secure licenses through their national regulatory bodies, which, in turn, submit a general outline of the satellite proposal—including details on the intended frequencies and orbits—to the ITU during the early planning stages, on behalf of satellite companies (Byers & Boley 2023). Moreover, unauthorized access to satellite networks represents a significant national security concern, particularly when it compromises intelligence and surveillance capabilities. Unauthorized access is defined as the unlawful infiltration of satellite networks by state or non-state actors, which allows them to intercept, manipulate, or disrupt the flow of information. This is an espionage risk, as confidential state or commercial data could be compromised, threatening the operational integrity of critical national infrastructure that may depend on satellite systems. The sovereignty of a nation is inherently tied to its ability to control and protect its communication channels and surveillance capabilities.

The ITU follows the principle of equity, recognizing that every state has a natural right to gain access to space (Copiz 2002). Such provisions are contained in Article 44(2) of the ITU Convention, designated specifically and quite exclusively to the GEO, which is located approximately 35,785 km (22,236 miles) above the equator. However, the prevalent “first come, first served” policy for allotting orbital slots and frequencies has raised concerns. As developing countries strive to launch their satellites using innovative technologies, they may find that the GEO is already saturated (Cappella 2019). In this regard, Article 44 emphasizes the special character of zones such as the GEO, stressing that radio frequencies and satellite orbits are restricted natural wealth, which should be used with reason, effectiveness, and economy.

Therefore, all member states are obliged to control the continuous utilization of these resources, considering the special requirements of developing countries. Furthermore, the principle of equitable access is embedded in the preface to the radio regulations. Remarkably, Article 44, Clause 2 of the ITU Constitution facilitates the conception of equitable access as a prerequisite for the economical and efficient usage of orbits. The same issue has been a concern regarding the growing number of mega satellite constellations in LEO.

The massive spectrum required for mega-constellations has intensified competition among operators. Due to the ITU “first-come, first-served” policy, spectrum slots are quickly claimed and reserved—often with little thought given to equitable access and coordination. In international orbit/spectrum resource management, the ITU Constitution, Convention, and radio regulations (Radio Regulations 2020), balance them to foresee the rights, responsibilities, and responsibilities of ITU member countries (ITU Constitution 1992). International treaties stipulate fundamental rules leading to fundamental characteristics such as the dispersal of radio frequencies among various radio communication services, fellow nations' entitlement to utilize orbital natural resources, and the global recognition of these benefits and rights.

In the Master International Frequency Register (MIFR), frequency allocations and any linked orbits, such as geostationary satellite orbits that are in use or anticipated to be used, are recorded. These guidelines serve as the cornerstone for the efficient use of orbital resources and the radio frequency spectrum, guaranteeing fair access and efficient international communication (UNOOSA & ITU 2015). A key aspect of ITU radio regulations for satellite services is maintaining non-interference in the operation of satellite networks while enabling the efficient, rational, economic, and justifiable deployment of orbital slots and radio frequency band resources.

Important procedural measures include the notification and fixation of certain radio frequencies in the MIFR, coordination among members, and the advance dissemination of certain information. This radio frequency spectrum enables international cooperation and communication by enabling the effective and efficient management of the radio frequency spectrum. Furthermore, there is a need for the worldwide acceptance of frequency usage, which includes all applications of radio frequencies. For instance, an aspiring satellite organization or non-government agency must check the MIFR before choosing a frequency.

Each administration that intends to launch operations in non-geostationary and geostationary fixed Satellite Services is typically required to submit an application to the ITU within two years of either making or commencing operations within the network. If such frequency allots are not utilized within the designated timeframe, a three-month notice will be issued to the administration concerned, and the ITU will cancel the frequency allocation. In addition, there is an urgent demand for developing a regulatory framework to ease the deployment of small-satellite constellations.

In international treaties directing space activities, there are various “soft law” documents that can be applied by both states and space operators. One of the key benefits of these soft law instruments is their flexibility in design and modification, as they do not impose a formal procedure for amendments. The only concern is the adoption of documents endorsed by the UN Committee on the Peaceful Uses of Outer Space, particularly when these documents are approved by consensus. The following documents affect the activities of satellites encompassed in various satellite constellations:

The United Nation General Assembly adopted a resolution suggesting that countries willingly offer more detailed and standardized information about the space objects they launch. This resolution aims to enhance the Registration Convention (1976; Convention on Registration of Objects Launched into Outer Space 1974), which requires states to register their space objects with the UN. The new recommendations and decisions include additional data, such as the date and time of a particular space object being launched, its orbital parameters, and the operational status of space objects, thereby allowing for better identification and tracking of such space objects in orbit (UNGA 2008).

The countries’ acceptance of liability in International Direct Television Broadcasting includes the provisions of responsibility, even for the control and management of the satellite orbits in the Indian-Oceanic region. “States are to undertake international responsibility for the activities associated with the satellite international direct television broadcasting which they conduct, or authorize to be conducted, within their jurisdiction” (von der Dunk 2019).

In 2019, UNCOPUOS adopted 21 Guidelines for the Long-Term Sustainability of Outer Space Activities, which address the critical issue of space debris mitigation in both the short and long term (UNOOSA 2019). As non-binding instruments, these guidelines provide a roadmap for space operators and manufacturers to selectively address the foundation for establishing minimum standards in the design of mega-constellations. Over several years, UNCOPUOS has been actively considering certain aspects of outer space activities and their sustainability. The Scientific and Technical Sub-Committee of this body has been working diligently to develop these guidelines, with particular attention to security and operational issues. The main purpose of these international guidelines is to ensure the sustainability of outer space activities, which could be challenged by problems such as the rapid rise of satellite constellations (MSCs), increased collision hazards, and growing space debris. These guidelines are very important and necessary and have gained official endorsement through a resolution aimed at addressing these challenges.

The implementation of these recommendations can further enhance the level of interstate cooperation for the nonaggressive use and utilization of activities in outer space. They apply equally to both governmental and non-governmental entities engaged in space activities. The guidelines have been organized into four sections: 1) It considers the methods for organizing and formulating policies for carrying out space operations; 2) It deals with the provision of safety and security of outer space; 3) It concentrates on comprehension, development, and international interaction; 4) It focuses on innovation in technology and research in science (UNOOSA 2021a).

An important institution facilitating international cooperation on space debris mitigation is the Inter-Agency Debris Coordination Committee (IADC) (IADC Space Debris Mitigation Guidelines 2002), which creates operational documents applicable to all space-related activities aimed at addressing the alarming issue of space debris—whether of natural or artificial origin (Yakovlev 2005). Managing space debris appears to be an important task, given that the guidelines offered by the IADC are not legally binding. The primary objective of these guidelines is to facilitate the coordination of research activities and the dissemination of relevant information among member space agencies, to the end that, debris delimitation approaches will be analyzed and effective transnational efforts aimed at the prevention of abusive practices in outer space will be reinforced. Moreover, the IADC guiding principle was useful to UNCOPUOS, as its recommendations were implemented.

In 2007, UNCOPUOS adopted seven Space Debris Mitigation Guidelines to reduce space debris and ensure sustainable outer space activities (UNCOPUOS 2007). Some of the issues that these guidelines seek to address are unintentional debris generated through normal operations, break-ups and collisions, intact spacecraft without a purpose in LEO and GEO, and the purposeful destruction of spacecraft. The degree of commitment of the states to implement these guidelines varies. Some states have adopted national laws to address this issue, registering laws based on these guidelines (Larsen 2017). Accordingly, these states prohibit the launching of small satellite constellations until it is demonstrated that their operations cause no damage to space vehicles or their components while performing regular operations. In addition, these licenses aim to promote the prohibition of harmful or destructive behaviors in space, constrain post-mission break-ups due to stored energy, and mandate the deorbiting of spacecraft after completing low-Earth missions.

These “voluntary guidelines” are followed informally on a global scale, without any legal sanctions for non-compliance. Such guidelines are, therefore, not fully adhered to by states or private space operators. In addition, because of the absence of a proper framework for enforcement, certain space activities contribute more debris than is acceptable (Mejía-Kaiser 2020).

The Code of Conduct for Space Debris Mitigation is a voluntary, self-regulatory instrument expected to be adopted by the ESA and national space agencies in Europe, along with their contractors. While these standards were established by the ESA, these shortcomings were addressed in relation to additional efforts by the Centre National D’Études Spatiales, which included debris mitigation strategies, safety concerns, and recommendations concerning space debris (Alby 2004).

These standards describe the precautions that must be integrated when designing and using space platforms to eliminate or reduce the chances of producing space debris. It also provides guidance on securing space objects from the danger of space collisions and proposes access methods for carrying out the directives and procedures specified in the standards regarding space operations. European space industries, national space agencies, and all stakeholders involved in the design, construction, launch, exploration, enhancement, program execution, planning, or management of missions, ‘within’ and ‘outside’ Europe, are expected to follow and apply the recommendations aimed at ESA guidance. All spacecraft in orbits around the Earth must abide by the established standards. It is essential for stakeholders to consult the Debris Mitigation Handbook, published by the ESA, before reviewing the directives contained in these guidelines (Wouters et al. 2016).

Rapid advancements in satellite technology and mega-constellations have surpassed the development of international space law, which remains fragmented and outdated (Abashidze et al. 2022). The primary legal framework governing these activities is the 1967 OST (OST 1967). This Treaty establishes two key principles for satellite constellations. It serves as the foundational legal framework for space activities but faces significant challenges in addressing the complexities of modern mega-constellations. Article I of the OST states that outer space is free for exploration and use by all states without discrimination. However, this principle does not account for the saturation of Earth's orbits owing to mega-constellations, which may effectively limit access for other satellites and actors, raising concerns about the equitable use of space resources. Article II prohibits any state from claiming sovereignty over outer space or celestial bodies (OST 1967).

This principle aims to prevent exclusive rights in space; however, the deployment of large satellite constellations may lead to the de facto appropriation of orbital slots, hindering other nations' abilities to operate in these regions (Johnson 2020). Article VI mandates that states bear international obligations for national activities in outer space, whether acted upon by governmental or non-governmental entities. This provision emphasizes that states must ensure compliance with the OST's principles; however, the treaty lacks specific enforcement mechanisms to address violations related to mega-constellations.

Article VII addresses the liability for harm triggered by space objects (LC 1972). As the volume of satellites increases, so does the risk of collisions and the resulting debris, which could lead to significant damage to the Earth or in orbit. The OST provides a framework for liability but lacks robust mechanisms for managing the risks associated with increased satellite traffic.

Despite these provisions, OST is often criticized as outdated and insufficient for regulating the rapid growth of commercial space activities and mega-constellations. Its vague language and reliance on principles, rather than binding rules, limit its effectiveness in ensuring sustainable practices in space. It should be amended to include more detailed regulations and binding rules that can adapt to new technologies and operational realities, specifically tailored to manage mega-constellations and their impact on space traffic and debris.

These principles have also led to succeeding treaties, including the 1972 LC, which outlines state liability for damage caused by space objects, and the Registration Convention, which dictates the registration of launched objects and distribution of information to the UN Secretary-General (Registration Convention 1976). While existing treaties grant a foundation, they must be renewed to effectively manage the unique challenges posed by modern satellite technologies.