MarIus

3.1.1 Article 27 Analysis: Objectives

The BBNJ’s Article 27 sets out the objectives of Part IV: to establish processes, thresholds, and requirements for conducting and reporting EIAs; to ensure that relevant activities are assessed and conducted so as to prevent, mitigate, and manage significant adverse impacts; and to support the consideration of cumulative impacts. Article 27 also explicitly states that one of the objectives of the EIA section is to "provide for strategic environmental assessments" and to support the establishment and enhancement of Parties' capacities to prepare, conduct, and evaluate EIAs.(1) De Lucia and Iavicoli, "From Outer Space to Ocean Depths." These objectives are directly applicable to splashdown operations, where hundreds of events over five decades have produced cumulative effects that remain scientifically uncertain.(2) De Lucia and Guo, “Assessing before Sinking.”

3.1.2 Article 28 Analysis: General Obligation

Article 28 of the BBNJ establishes the general obligation for States Parties to conduct EIAs in respect of planned activities under their jurisdiction or control that take place in ABNJ.(3) BBNJ, art. 28(1); see Section 2.1.2 above on the "jurisdiction or control" allocation framework. Two features of the provision are of particular significance for the analysis of splashdown operations.

The first is the pre-authorisation character of the obligation. Under Article 28(1), the EIA must be conducted before the activity is authorised; a post-hoc assessment conducted after a splashdown has occurred cannot satisfy the obligation.(4)Pulp Mills, I.C.J. Reports 2010, para. 205; Tanaka, "Reflections on the EIA in the BBNJ," 95–96. For future splashdown operations, including the ISS deorbit planned for no earlier than 2030, the obligation is already in force for all States Parties.(5) De Lucia and Guo, "Assessing before Sinking," 1–29.

The second, and more consequential, feature is the pathway established by Article 28(2), which extends the EIA obligation to activities conducted within national jurisdiction where a Party determines that the activity "may cause substantial pollution of or significant and harmful changes" to the marine environment in ABNJ. As established in Section 2.4.3, the deorbit burn initiating a controlled reentry is carried out beyond national jurisdiction, but it is authorised through a domestic licensing framework. Launch authorisation decisions are exercises of State authority within the national legal order and therefore constitute activities "within national jurisdiction".(6)Vienna Convention on the Law of Treaties, art. 31(1); BBNJ, art. 28(2). The legally operative question is not where the authorisation is physically executed, but whether the activity it approves may cause substantial pollution or significant and harmful changes to the marine environment in ABNJ. Where the licensed activity involves a controlled splashdown on the high seas, that causal nexus is integral to the authorisation itself: the purpose of the licence is to permit the deposition of a space object in the marine environment of ABNJ. Article 28(2) is accordingly engaged as a matter of ordinary textual interpretation.(7) BBNJ, art. 28(2); UNCLOS, art. 206.

The inadequacy of existing practice is illustrated by NASA's 1996 EIA for the International Space Station, which acknowledged open ocean areas as part of the affected environment but confined its analysis to the risk of debris physically striking marine life near the surface, without addressing marine ecosystem impacts.(8) National Aeronautics and Space Administration, International Space Station Final Environmental Impact Statement, NASA Technical Report 19960053133 (1996). The obligation under Article 28 as operationalised through Part IV demands a qualitatively different and substantially more rigorous inquiry.

That inquiry proceeds through the procedural pathway established by Part IV: screening to determine whether the licensed activity may have more than a minor or transitory effect on the marine environment in ABNJ, or whether its effects are unknown or poorly understood; scoping of the issues, impacts, and mitigation measures to be addressed; preparation of an EIA before authorisation using the best available science; public notification and publication through the Clearing-House Mechanism; a reasoned decision-making stage at which EIA findings are taken into account before the activity proceeds; and post-authorisation monitoring, reporting, and review.(9) BBNJ, arts. 30–37; Tanaka, "Reflections on the EIA in the BBNJ," 99–102; see Section 3.1.4 below for analysis of each procedural stage. A State may discharge these obligations through its own national EIA process, provided that process satisfies the BBNJ’s equivalency, notification, and transparency requirements.(10) BBNJ, arts. 29(4)–(5); see Section 2.2 above on the "not undermine" clause and the equivalency framework.

For splashdown and reentry operations, Article 28(2) is the strongest textual basis for BBNJ EIA obligations precisely because it captures the authorisation decision rather than requiring the physical activity to occur within ABNJ. The deorbit burn is an act of implementation; the legally operative moment is the national licensing decision that precedes it. A State that approves a debris mitigation plan designating the high seas as the intended endpoint has taken an action within national jurisdiction whose effects in ABNJ are not merely foreseeable but intentional. A domestic characterisation of the authorisation as an administrative act without extraterritorial effect cannot displace the Article 28(2) obligation: it is the extraterritorial effect, the deposition of a space object in the marine environment of ABNJ, that the authorisation is designed to bring about.(11) De Lucia and Guo, "Assessing before Sinking," 1–29; Pozdnakova, "Pollution of the Marine Environment by Spaceflights," 87–88.

3.1.3 Article 29 Analysis: Relationship with Other EIA Processes and the Exemption Question

Article 29(4) provides that it is not necessary to conduct a screening or EIA of a planned activity in ABNJ if the potential impacts of the planned activity or category of activity have been assessed in accordance with the requirements of other relevant legal instruments or frameworks or by relevant global, regional, subregional or sectoral bodies. This is the operative exemption provision, and it must be examined carefully in the splashdown context.

Applying the BBNJ’s EIA framework to space object reentries is not without controversy in practice. States with significant commercial space programmes, including the United States and Russia, neither of which had ratified the BBNJ as of the date of this thesis,(12) BBNJ, Status of Ratification. have not endorsed the view that splashdown operations require marine environmental assessment. The cost and operational flexibility implications for commercial launch operators, and the potential for EIA obligations to constrain urgent end-of-life disposal decisions, are practical objections that warrant acknowledgement. This thesis does not argue that the BBNJ framework should apply to splashdowns as the preferred application of policy; rather that it applies as a matter of existing international law.

A launching state might argue that the UNCOPUOS Space Debris Mitigation Guidelines and the IADC framework constitute an assessment under "other relevant legal instruments or frameworks," such that no BBNJ EIA is required for compliant splashdowns. This chapter argues that the exemption does not apply for two reasons. First, the UNCOPUOS guidelines contain no environmental impact assessment of the marine environment; they address orbital sustainability and focus on potential impacts to humans, not oceanic ecology. The "assessment" required for the Article 29(4) exemption must be an assessment of the potential impacts on the marine environment, the subject matter the BBNJ is designed to address. A space debris mitigation assessment focused exclusively on collision risk in low Earth orbit is categorically different in subject matter. Second, Article 29 also requires information exchange for activities already assessed under existing EIA mechanisms(13) Ross Harper, “Planetary Protection: A New Launch Pad for the Regulation of the Commercial Space Industry,” California Western International Law Journal 50, no. 1 (2020), https://scholarlycommons.law.cwsl.edu/cwilj/vol50/iss1/8. and, to date, no such exchange has taken place in the splashdown context. This points to a gap in the space law framework, evidencing that its application not been understood, by any state, as constituting an EIA for purposes of the marine environment.

Article 29 establishes a series of mechanisms to better align the EIA provisions at the global, regional, sub-regional, and sectoral levels, and read in combination with Article 38, seek to promote the application of BBNJ EIA standards to relevant bodies. This suggests that the appropriate response for the space sector is not to invoke Article 29(4) as an exemption but rather for states and UNCOPUOS to develop sector-specific EIA guidelines that meet BBNJ standards, an important step towards aligning the existing regulatory frameworks and removing ambiguities in Treaty applications. Under Article 29(1), Parties are required to promote the BBNJ’s EIA standards within the international frameworks and bodies to which they belong, including UNCOPUOS.(14) Tanaka, "Reflections on the EIA in the BBNJ," 95–96. Under Article 29(3), the Conference of the Parties is mandated to collaborate with relevant bodies to develop or update EIA standards and guidelines. States Parties to the BBNJ who are UNCOPUOS members are therefore under a positive obligation to promote BBNJ-compatible EIA standards in the space governance context. The coherence mechanisms in Articles 5 and 29 function not merely as a shield against regime conflict, but as an active instrument of normative convergence between space law and marine law.

3.1.4 Article 30 Analysis: Screening

The threshold for screening centers on planned activities which may have more than a minor or transitory effect on the marine environment, or the effects of the activity are unknown or poorly understood.(15) BBNJ, art. 30(1). The factors informing that determination include the type of activity and technology used, the ecological characteristics of the location, the potential for cumulative impacts, and the extent to which effects remain unknown.(16) Ibid., art. 30(2). Splashdown operations independently satisfy both limbs of the threshold.

On the first limb, the limited understanding of the environmental effects of splashdown activities make it difficult to characterize them as minor or transitory. Space debris contains hazardous substances, including propellant residues acutely toxic to aquatic organisms and metallic particulates documented to accumulate in the water column, whose deposition in the marine environment constitutes more than a negligible impact.(17) Pozdnakova, "Pollution of the Marine Environment by Spaceflights," 77, 84–85; Byers and Byers, "Toxic Splash," 580–91 The cumulative effect of over 260 space objects deposited in the spacecraft cemetery over five decades represents a continuous and progressive environmental stressor irreconcilable with any ordinary understanding of a transitory impact.(18) De Lucia and Iavicoli, "From Outer Space to Ocean Depths," 368–70; Baker et al., Natural Capital and Exploitation of the Deep Ocean.

This conclusion is reinforced by the 2025 revision of the IADC Space Debris Mitigation Guidelines, which for the first time expressly acknowledges that ground environmental pollution "caused by radioactive substances, toxic substances or any other environmental pollutants resulting from on-board articles, should be prevented or minimized."(19) IADC, Space Debris Mitigation Guidelines(2025 rev.), UN Doc. A/AC.105/C.1/2025/CRP.9. The significance of this development is twofold. First, it forecloses any characterisation of marine environmental impacts from splashdowns as trivial or negligible. Second, the IADC Guidelines represent the most developed expression of environmental awareness within the UNCOPUOS regulatory architecture and constitute the space law regime's closest existing analogue to an environmental risk-management framework. Their non-binding character and absence of any verification or enforcement mechanism means, however, that a general acknowledgement that pollution "should be prevented or minimized" falls far short of the procedural obligations imposed by Part IV of the BBNJ. The Guidelines' evolution in a more environmentally conscious direction is consistent with the principle, affirmed in the ITLOS Climate Change Advisory Opinion, that the due diligence standard develops as scientific understanding advances, a trajectory that reinforces rather than displaces the BBNJ EIA obligation.(20)Request for Advisory Opinion(ITLOS, 2024); Sands and Peel, Principles of International Environmental Law, 605.

On the second limb, the effects of splashdown operations on the marine environment remain unknown or poorly understood. No systematic monitoring of the spacecraft cemetery exists; the deep-sea ecosystems of the South Pacific Oceanic Uninhabited Area have been minimally studied; and the long-term consequences of progressive material accumulation on the ocean floor are not well characterised.(21) Lawrence et al., "The Case for Space Environmentalism," 428–35; This epistemic deficit does not extinguish the EIA obligation, the precautionary approach requires preventive action precisely in conditions of scientific uncertainty. It does, however, present a methodological challenge for any EIA conducted on the basis of existing scientific knowledge, reinforcing the necessity of baseline environmental assessment as an integral component of the scoping exercise.

Beyond individual EIA assessments, Article 39 of the BBNJ establishes a framework for strategic environmental assessments, including authority for the Conference of the Parties to initiate an SEA motu proprio in respect of an entire ocean area or region.(22) BBNJ, arts. 39(1)–(2); Tanaka, "Reflections on the EIA in the BBNJ," 109–10. This power could be exercised in relation to the spacecraft cemetery to collate information about deposited space objects, assess cumulative impacts, and identify data gaps and research priorities. The COP's capacity to initiate such an assessment without requiring the consent of individual States constitutes a significant institutional innovation in international environmental governance with direct application to the spacecraft cemetery, and has no parallel in the existing space law framework.(23) De Lucia and Guo, "Assessing before Sinking," 1–29; Tanaka, "Reflections on the EIA in the BBNJ," 109–10.

3.1.5 Articles 31–34 Analysis: EIA Process, Content, Publication, and Decision-Making

Where screening concludes that an EIA is required, Part IV establishes a procedural pathway through Articles 31 to 37 governing scoping, assessment, publication, decision-making, and monitoring. This section addresses the content, publication, and decision-making stages; the screening threshold is addressed in Section 3.1.4 above.

The minimum content of the EIA report is specified in Article 33(2) and includes: a description of the planned activity and the results of the scoping exercise; a baseline assessment of the affected marine environment; a description of potential impacts, including cumulative and transboundary impacts; proposed prevention, mitigation, and management measures; an account of uncertainties and gaps in knowledge; information on the public consultation process; and a non-technical summary.(24) BBNJ, art. 33(2); Tanaka, "Reflections on the EIA in the BBNJ," 97–98. Each of these requirements, if applied to the ISS deorbit, would demand forms of investigation and disclosure not previously required for splashdown operations. Most consequentially, a baseline assessment of the ecological state of the spacecraft cemetery, the condition of the South Pacific Oceanic Uninhabited Area prior to further debris deposition, does not currently exist and would need to be commissioned before any future authorisation could be granted.(25) Baker et al., Natural Capital and Exploitation of the Deep Ocean; De Lucia and Iavicoli, "From Outer Space to Ocean Depths," 368–70;

The publication requirements under Article 33(3)–(5), the obligations arising from the Clearing-House Mechanism, and the institutional disparity between the BBNJ EIA architecture and the UNCOPUOS voluntary framework and its implications for the Article 5 analysis are addressed in Section 2.2 above.

Article 34 governs the decision-making stage. The BBNJ does not transfer decision-making authority to the Conference of the Parties or the Scientific and Technical Body; States retain sovereignty over their authorisation decisions.(26) BBNJ, art. 34(1). However, Article 34(2) imposes a substantive constraint on the exercise of that discretion: where an EIA demonstrates that significant adverse impacts are likely, the authorising Party must ensure that measures to prevent, mitigate, and manage such impacts are identified and that the activity is conducted accordingly.(27) BBNJ, art. 34(2); Pulp Mills on the River Uruguay, Judgment, I.C.J. Reports 2010, para. 205. This provision imports a concrete substantive standard into what might otherwise be read as a purely procedural framework. A Party that completes an EIA identifying significant adverse marine environmental impacts cannot proceed to authorise the activity without addressing those findings. Applied to splashdown operations, a State conducting a BBNJ-compliant EIA that identifies significant marine environmental impacts would be required, as a matter of treaty obligation, to impose conditions on or decline to authorise the proposed operation.

3.1.6 Article 35 Analysis: Monitoring and Review

Article 35 requires States Parties to maintain ongoing surveillance of the impacts of activities in ABNJ that they permit or in which they engage, and to monitor the environmental impacts of authorised activities against the conditions set out in the approval decision.(28) BBNJ, arts. 35–36; The provision's particular significance in the splashdown context lies in its engagement with cumulative impact assessment. As established early in this paper, the BBNJ defines cumulative impacts as the combined effects of an activity together with those of past, present, and reasonably foreseeable activities.(29) BBNJ, art. 1(6); see Section 2.5 above. The spacecraft cemetery exemplifies this; a product of the repetition of similar activities over more than fifty years. Its future trajectory, incorporating the ISS deorbit and continued commercial splashdowns, involves reasonably foreseeable activities of significant and increasing scale.

The cumulative dimensions of the problem are substantial. The spacecraft cemetery has received over 260 objects since the 1970s, ranging from small satellites to the 130-tonne Mir space station.(30) De Lucia and Iavicoli, "From Outer Space to Ocean Depths," 366–68; García, "The Spacecraft Cemetery at the Loneliest Point on Earth." The ISS deorbit planned for 2030 will deorbit a further approximately 420 tonnes of material in a single event, a mass that exceeds by an order of magnitude any ordinary reading of the "minor or transitory" threshold in Article 30(1).(31) NASA, International Space Station Transition Report (January 2022); BBNJ, art. 30(1). Commercial reentry operations compound this trajectory: Starlink operations alone currently account for approximately forty per cent of all annual satellite reentries globally, each depositing aluminium alloy fragments, composite materials, and residual propellants into the same confined ocean zone.(32) Bennett, "Orbital Debris Requires Prevention and Mitigation across the Satellite Life Cycle," 95; Thibaut Maury et al., "Space Debris through the Prism of the Environmental Performance of Space Systems: The Case of Sentinel-3 Redesigned Mission," Journal of Space Safety Engineering 7 (2020): 198–205, https://doi.org/10.1016/j.jsse.2020.07.002. These figures are not isolated data points; they constitute the empirical foundation for the cumulative impact analysis that Article 35's monitoring framework is designed to support.

A monitoring framework under Article 35 would, for the first time, require systematic data collection on the environmental condition of the South Pacific Oceanic Uninhabited Area and create a mechanism through which the aggregate effects of splashdown operations become legally cognizable as a matter of treaty obligation. This transformation from the current characterisation of individual events as isolated and negligible to a regime of systematic cumulative assessment is directly engaged by Article 27's objective of supporting the consideration of cumulative impacts in EIA procedures conducted under Part IV.(33) BBNJ, art. 27; De Lucia and Guo, "Assessing before Sinking," 1–29.

The relationship between Article 35 and the existing space law framework warrants direct statement. The ITLOS Climate Change Advisory confirmed that compliance with an external regulatory regime does not carry any automatic implication of compliance with the more stringent obligations of the law of the sea concerning marine environmental protection.(34) ITLOS, Advisory Opinion, para. 232; BBNJ, arts. 5, 35. States cannot rely on adherence to the IADC Guidelines as discharging their Article 35 monitoring obligations. The two frameworks are additive, not substitutive: BBNJ monitoring obligations attach independently of and in addition to whatever obligations arise under the space debris mitigation framework.