4.2 Areas for Further Research
First, the thesis has argued that the BBNJ applies to splashdowns but has not examined how States would comply in practice. A detailed study of the institutional and procedural architecture of BBNJ compliance in the space sector, including the role of national licensing regimes, the Scientific and Technical Body, the Clearing-House Mechanism, and the Conference of the Parties, would be a valuable practical contribution. In particular, the question of how UNCOPUOS and the BBNJ Conference of the Parties would coordinate on sector-specific EIA guidelines, as contemplated by Article 38 of the BBNJ, warrants close examination. The proposed EU Space Law Regulation (2025), which introduces environmental footprint declarations for space operators, may offer an early model of how national regulatory frameworks can be adapted to accommodate marine environmental requirements.(1) European Commission, Proposal for a Regulation on the Safety, Resilience and Sustainability of Space Activities in the Union (EU Space Act), COM(2025) 345 final (25 June 2025), arts. 96–100.
Second, the thesis has focused on the obligations of State Parties to the BBNJ. A broader study of the position of non-Parties, including major spacefaring States that may not ratify the BBNJ, would be valuable. The relevant question is whether and to what extent the EIA obligation binds non-Parties as a matter of customary international law, particularly in light of the ITLOS and ICJ jurisprudence establishing EIA as a general customary rule. The progressive development of customary law in this area, and its potential to bind States that decline to ratify the BBNJ, deserves sustained scholarly attention.
Third, the thesis has noted the scientific uncertainty surrounding the environmental impacts of splashdown operations but has not undertaken a detailed scientific review. A genuinely interdisciplinary study, combining legal analysis with oceanographic, ecotoxicological, and chemical evidence, is required for further evidence-based discussions on impact of space debris in the high seas using the best available science. In particular, data on the bioaccumulation of metallic particulates from disposed of satellites in food webs, and on the long-term effects of legacy contamination in the spacecraft cemetery, would potentially ground claims of significant harm under Article 206 UNCLOS and Article 30 of the BBNJ. The observation that no systematic monitoring programme exists for the spacecraft cemetery is itself a finding that invites urgent interdisciplinary response.
Fourth, this thesis has been confined to activities in ABNJ. The question of reentries over or within territorial waters and exclusive economic zones raises distinct jurisdictional issues, including coastal State rights to require EIAs for activities in their EEZ and the applicability of UNCLOS Article 56, that could form the basis of a separate study. Similarly, the legal status of uncontrolled reentries that cannot be attributed to any deliberate planning decision raises unresolved questions of State responsibility and liability under the OST Liability Convention framework that this thesis has not addressed.
Fifth and finally, the thesis has operated at the level of the obligation to conduct an EIA. A natural extension of this research would examine the substantive content of the no-harm obligation: assuming a fully compliant EIA were conducted and demonstrated significant adverse impacts, what follows? Does the BBNJ prohibit the activity, require alternatives analysis, or merely require mitigation? The interaction between the procedural EIA obligation and the substantive no-harm rule under Article 6 of the BBNJ, and the extent to which Article 34’s obligation to prevent significant adverse impacts functions as a de facto substantive veto, merits detailed doctrinal analysis that lies beyond the scope of this thesis but would be a significant contribution to the emerging law of ABNJ governance.
The governance of outer space and the high seas has long been treated as the province of two separate legal communities, operating with separate instruments, separate institutions, and separate scholarly traditions. The physical reality of space object reentry has always complicated that separation; the entry into force of the BBNJ has now given it legal consequence. The challenge for international law, and for the States that make and apply it, is to develop the institutional, procedural, and normative infrastructure to manage that consequence responsibly. This thesis has sought to contribute to that project by clarifying the legal foundations and identifying the normative obligations that already exist. The work of building compliance frameworks to discharge those obligations remains to be done.