1 Report of the Scientific and Technical Subcommittee on its fifty-seventh session, UN Doc. A/AC.105/1224 (2020), at 19, para. 104.

2 1966 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, 610 UNTS 205. As of 1 January 2020, the OST is binding on 110 states. Moreover, 23 states have signed it and are therefore obliged to refrain from acts which would defeat the object and purpose of the treaty under Art. 18 VCLT.

3 S. Marchisio, Protecting the Space Environment, in Proceedings of the 46^th Colloquium on the Law of Outer Space, 2003, at 11. Sustainability has gained considerable importance in the conduct of space activities and the issue is currently being examined by the Scientific and Technical Sub-committee of UNCOPUOS under the Agenda item ‘Long-Term Sustainability of Outer Space Activities’. The Sub-Committee put this item on its agenda in 2010. See Report of the Committee on the Peaceful Uses of Outer Space, UN Doc. A/64/20 (2009), at 23, para. 161.

4 Report of the Committee on the Peaceful Uses of Outer Space, UN Doc. A/74/20 (2019), at 12, para. 71, and at 17, para. 116 (2019 UNCOPUOS Report); cf. ‘Decision No 541/2014/EU of the European Parliament and of the Council of 16 April 2014 establishing a Framework for Space Surveillance and Tracking Support’, (2014) Official Journal of the European Union 158, at 228, recital no. 7.

5 For the qualification of orbits as ‘limited natural resources’, see Constitution of International Telecommunication Union Art. 44.

6 The UNCOPUOS is a subsidiary organ of the General Assembly, under Art. 22 of the UN Charter. Its internal division, which consists of two sub-committees, the Scientific and Technical Sub-committee and the Legal Sub-committee, was created to link the legislative process of international space law with rapid advances in technology and science.

7 See the 2019 Guidelines for the Long-term Sustainability of Outer Space Activities, UN Doc. A/AC.105/C.1/L.366 (2019), in particular Guideline A.2, para. 2(b), B.3 and D.2 (hereafter Long-term sustainability Guidelines).

8 Report of the Legal Subcommittee on its fifty-eighth session, UN Doc. A/AC.105/1203 (2019), at 24, para. 163; Report of the Scientific and Technical Subcommittee on its fifty-sixth session, UN Doc. A/AC.105/1202 (2019), at 21, para. 123. In contrast with this optimistic view, it should, however, be remembered that most mitigation measures introduce some burden on missions. For instance, requiring each satellite to be equipped with de-orbiting capacity would also mean that states would have to reserve the last bit of fuel to de-orbit the satellite with an ensuing reduction in the length of use of the satellite. See L. Viikari, The Environmental Element in Space Law (2007), at 4.

9 Report of the Scientific and Technical Subcommittee, ibid., at 121, paras. 124–125; Report of the Legal Subcommittee, ibid., at 24, para. 165; see also at 25, paras. 167, 168.

10 Report of the Legal Subcommittee, ibid., at 25, para. 173. See the 1974 Convention on Registration of Objects Launched into Outer Space (resolution 3235 (XXIX), annex), 1023 UNTS 15.

11 Report of the Scientific and Technical Subcommittee, supra note 1, at 19, para. 105.

12 Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space (Report of the Committee on the Peaceful Uses of Outer Space, UN Doc. A/62/20 (2007), at 17, paras. 118–119 and at 47–50, Annex) (hereafter UNCOPUOS Guidelines).

13 UNCOPUOS Guideline 3 (Limit the probability of accidental collision in orbit).

14 Collisions between satellites produce a number of fragments, some of which may be capable of fragmenting another object on collision creating even more fragments. The result would be an exponential increase in the number of objects over time, creating a self-sustaining debris belt around the Earth. This is also known as the Kessler Effect. See D. J. Kessler and B. G. Cour-Palais, ‘Collision Frequency of Artificial Satellites: The Creation of a Debris Belt’, (1978) Journal of Geophysical Research 2637–46.

15 ILA Draft International Instrument on the Protection of the Environment from Damage Caused by Space Debris, Art. 1(c), adopted by the Sixty-Sixth Conference of the International Law Association, Buenos Aires, 1994. The text can be found in K. H. Böckstiegel, ‘ILA Draft Convention on Space Debris’, (1995) 44 ZLW 29 –34. A satellite with a payload which is no longer able to transmit data to Earth is no longer active, but it could continue to be useful because of the information stored on board.

16 See the combination of Arts. 3.1 and 3.2.1 of the Inter-Agency Space Debris Mitigation Committee (IADC) Space Debris Mitigation Guidelines, Revision 1 – September 2007. See also the similar definition of space debris provided in Art. 2, no. 18 of the Proposal for a Regulation establishing the space programme of the Union and the European Union Agency for the Space Programme, COM/2018/447 final, 2018/0236 (COD).

17 International cooperation in the peaceful uses of outer space, A/RES/62/217 (2007), at 6, para. 26. This paragraph was part of the resolution adopted without a vote.

18 Ibid., at 7, para. 27. The Scientific and Technical Subcommittee recognizes that they have been adopted or implemented so far by several states and international organizations. See, Report of the Scientific and Technical Subcommittee, supra note 1, at 18, para. 97. The Long-term sustainability Guideline A.2 recommends that states should further ‘implement space debris mitigation measures, such as the Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space’. For an overview of international practice see the Compendium of Space Debris Mitigation Standards adopted by states and international organizations, available at www.unoosa.org/oosa/en/ourwork/topics/space-debris/compendium.html.

19 IADC Guideline 3.2.1 (emphasis added).

20 IADC Guidelines Art. 3.2.1; ILA Draft Convention Art. 1(c).

21 In this sense see C. Q. Christol, Scientific and Legal Aspects of Space Debris, in Proceedings of the 36^th Colloquium on the Law of Outer Space, 1993, at 372; L. Perek, Legal Aspects of Space Debris: A View from Outside the Legal Profession, in Proceedings of the 38^th Colloquium on the Law of Outer Space, 1995, at 53.

22 One might think of the collision which took place in 2009 between the American Iridium 33 satellite, which was still active at the time, and Cosmos 2251, a no longer functional Russian satellite.

23 In this sense see M. K. Force, When the Nature and Duration of Space Becomes Appropriation: “Use” as a Legal Predicate for a State’s Objection to Active Debris Removal, in Proceedings of the 56^th Colloquium on the Law of Outer Space, 2013, at 415.

24 See ITU Radio Regulations, 2016 Edition Art. 11 (Notification and recording of frequency assignments).

25 P.-M. Martin, ‘Les Débris Spatiaux: Remarques sur le Visible et l’Invisible en Droit’, (1994) 43 ZLW 30–7, at 35.

26 On space debris removal see infra Section 10.

27 1974 The Convention on Registration of Objects Launched into Outer Space Art. IV (hereafter Registration Convention).

28 On the limits of the Registration Convention see F. Von der Dunk, Space Debris and the Law, Proceedings of the Third European Conference on Space Debris, 2001, at 865; P. D. Man, ‘The Relevance of ITU Regulations for Clarifying the Space Debris Concept and Strengthening Guidelines on the Removal of Satellites at the End of Their Functional Life’, (2013) 38 Annals of Air & Space Law 203–36, at 214–16.

29 Cf. Recommendations on enhancing the practice of states and international intergovernmental organizations in registering space objects, UN Doc. A/RES/62/101 (2007), at 3, para. 2(b). See also the Long-term Sustainability Guideline A.5, which recommends that states and international intergovernmental organizations should take into account General Assembly resolution 62/101.

30 1972 Convention on International Liability for Damage Caused by Space Objects, 961 UNTS 187. See M. Pedrazzi, danni causati da attività spaziali e responsabilità internazionale (1996), at 82–9, 110–22; F. Von Der Dunk, supra note 28, at 863–8.

31 In general, for authors supporting that liability regimes are not appropriate tools for international environmental protection, see J. Brunnée, ‘Of Sense and Sensibility: Reflections on International Liability Regimes as Tools for Environmental Protection’, (2004) 53 ICLQ 2, 351–68; T. Scovazzi, ‘State Responsibility for Environmental Harm’, (2001) 12(1) Yearbook of International Environmental Law 43–67, at 51. See also the well-known passage in the ICJ’s Gabcikovo judgment: ‘The Court is mindful that, in the field of environmental protection, vigilance and prevention are required on account of the often irreversible character of damage to the environment and of the limitations inherent in the very mechanism of reparation of this type of damage.’ Gabcikovo-Nagymaros Project (Hungary/Slovakia), Judgment of 25 September 1997, [1997] ICJ Rep. 7, at 74, para. 140.

32 For a broad interpretation of the term ‘space object’ encompassing space debris see, ex multis, P. Stubbe, State Accountability for Space Debris (2018), at 373–5, 388–90.

33 See the wording of Art. VII OST and the definition of damage in Art. I(a) of the Liability Convention.

34 L. Condorelli, ‘La réparation des dommages catastrophiques causés par les activités spatiales’, in La réparation des dommages catastrophiques (1990), at 288–90. The ILA Draft Convention extends the notion of damage to cover ‘any adverse modification of the environment of areas within or beyond national jurisdiction or control’.

35 On the limits of the application of the liability regime to space debris see T. G. Nelson, ‘Regulating the Void: In-Orbit Collisions and Space Debris’, (2015–2016) Journal of Space Law 105–30, at 114–21, 123–4.

36 For instance, it was proposed that each state should contribute to the Fund according to its ‘actual use’ of the space ‘environment’, and a useful indicator for this purpose could be the profit made from or the cost involved in launches. S. Ospina, Outer Space: ‘Common Heritage’ or ‘Common Junkyard’ of Mankind?, in Proceedings of the 30^th Colloquium on Outer Space Law, 1987, at 231. See also A. N. Pecujlic and S. K. Germann, ‘Global Cap and Trade System for Space Debris: Putting a Price on Space Hazards’, (2015–2016) Journal of Space Law 131–45.

37 On the reparative function of liability see R. Lefeber, Transboundary Environmental Interference and the Origin of State Liability (1996).

38 On the origins of Article IX OST see S. Marchisio, ‘Article IX’, in S. Hobe, B. Schmidt-Tedd and K.-U. Schrogl (eds.), Cologne Commentary on Space Law (2009), vol. 1, at 556–60.

39 On this point see infra Section 10.

40 In this sense, see also P. Achilleas, Planetary Protection-Legal Issues, in Proceedings of the 46th Colloquium on the Law of Outer Space, 2003, at 215. This author argues that the rule imposing avoidance of harmful contamination is a general principle of space law and, as such, is also applicable to the use of outer space. On this point see infra in the text.

41 The great majority of legal doctrine hinges on the alleged ambiguity of Art. IX, putting into doubt its effectiveness. See, ex multis, F. Lyall, Protection of the Space Environment and Law, in Proceedings of the 42^nd Colloquium on the Law of Outer Space, 1999, at 474; H. Almond, A Draft Convention for Protecting the Environment of Outer Space, in Proceedings of the 23^rd Colloquium on Law of Outer Space, 1980, at 101; N. Jasentuliyana, ‘Space Debris and International Law’, (1998) 26 Journal of Space Law 139–62, at 141; 159–60; L. Viikari, supra note 8, at 110–11. Even more trenchant is C. Gray: ‘Current space law has nothing to say about space debris.’ C. Gray, ‘Global Commons, Space Power and Strategy’, in ISPI Quaderni di relazioni internazionali (2008), at 10.

42 In this sense, but as a critical note, see S. Gorove, ‘Pollution and Outer Space: A Legal Analysis and Appraisal’, (1972) New York University Journal of International Law and Politics 53–66, at 62; Viikari, ibid., at 111.

43 See para. 2 of the OST preamble.

44 It is well-known that the rule was already applied in the Trail Smelter case (United States of America, Canada, 16 April 1938, 3 UNRIAA, at 1905–1982).

45 It is true that the 1969 Vienna Convention on the law of Treaties (VCLT), according to its Art. 4, only applies to treaties concluded after its entry into force on 27 June 1980 and can therefore not apply to the Outer Space Treaty. However, the International Court of Justice has repeatedly confirmed that Arts. 31 and 32 of the VCLT laying down the fundamental principles regarding the interpretation of treaties are a reflection of customary international law. See, ex pluribus, Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment of 20 April 2010, [2010] ICJ Rep. 14, at 46, para. 65.

46 ‘The existence of the general obligation of states to ensure that activities within their jurisdiction and control respect the environment of other states or of areas beyond national control is now part of the corpus of international law relating to the environment.’ Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion of 8 July 1996, [1996] ICJ Rep. 226, at 19, para. 29. For a critical assessment of the use of the expression ‘jurisdiction and control’ rather than ‘jurisdiction or control’ see E. B. Weiss, ‘Opening the door to the Environment and to Future Generations’, in L. B De Chazournes and P. Sands (eds.), International Law, the International Court of Justice and Nuclear Weapons (1999), at 340. The passage quoted was then recalled in the Gabcikovo-Nagymaros Project case, where the ICJ emphasized ‘the great significance that it attaches to respect for the environment, not only for States but also for the whole of mankind’. Gabcikovo-Nagymaros Project (Hungary/Slovakia), supra note 31, at 41, para. 53.

47 In the sense that the ‘no harm rule’ is an obligation of conduct see, ex multis, A. E. Boyle, ‘State Responsibility and International Liability for Injurious Consequences of Acts Not Prohibited by International Law: A Necessary Distinction?’, (1990) 39 ICLQ 1–26, at 14–15 and the literature it cites; A. Gattini, ‘International Responsibility of the State and International Responsibility of Judicial Persons for Environmental Damage: Where do we stand?’, in Y. Levashova, T. Lambooy and I. Dekker (eds)., Bridging the gap between International Investment Law and the Environment (2015), at 117; P. Birnie, A. Boyle and C. Redgwell, International Law and the Environment (2009), at 137; T. Scovazzi, supra note 31, at 49–50.

48 Contra, focusing on the wording of this part of Art. IX OST, P. Stubbe argues that this norm ought to be regarded as prohibiting contamination in absolute terms and obliging states to adopt a certain conduct to this end: P. Stubbe, supra note 32, at 158–62. However, the author himself then recognizes that Art. IX OST is the ‘space-specific’ expression of the no harm rule. Ibid., at 247.

49 In this sense see also Stubbe, ibid., at 158.

50 On the consultation mechanism established in Art. IX OST in the case of potential interference with other space activities see Section 8.

51 P.-M. Dupuy, ‘Soft Law and the International Law of the Environment’, (1991) 12 Michigan Journal of International Law 420–35, at 434.

52 The ITU Recommendation on environmental protection of the geostationary satellite orbit consistently specifies that ‘as little debris as possible should be released into the GSO region during the placement of a satellite in orbit’. Environmental protection of the geostationary-satellite orbit, Rec ITU-R S.1003-2 (12/2010).

53 According to the precautionary approach, when there are threats of ‘serious or irreversible damage’ to the environment, lack of scientific certainty cannot be invoked by states in order to postpone preventive measures (see principle 15 of the Rio Declaration). ‘This obligation applies in situations where scientific evidence concerning the scope and potential negative impact of the activity in question is insufficient but where there are plausible indications of potential risks. A sponsoring State would not meet its obligation of due diligence if it disregarded those risks.’ Responsibilities and obligations of States with respect to activities in the Area, Advisory Opinion, 1 February 2011, ITLOS Reports 2011, 10, at 46, para. 131. The Law of the Sea Tribunal has come the closest to acceptance of the customary nature of the precautionary approach: ‘it is appropriate to point out that the precautionary approach is also an integral part of the general obligation of due diligence of sponsoring states, which is applicable even outside the scope of the Regulations’. Ibid., para. 131. See also Pulp Mills, supra note 45, at 71, para. 164.

54 See Responsibilities and obligations of States with respect to activities in the Area, Advisory Opinion, ibid., at 48, paras. 136–137.

55 Cf. UNCOPUOS Guideline 1.

56 Responsibilities and obligations of States with respect to activities in the Area, Advisory Opinion, supra note 53, at 43, para. 117.

57 ‘The standard of due diligence against which the conduct of the State of origin should be examined is that which is generally considered to be appropriate and proportional to the degree of risk of transboundary harm in the particular instance.’ Para. 11 of the commentary to Art. 3, Draft Articles on Prevention of Transboundary Harm from Hazardous Activities.

58 Pulp Mills, supra note 45, at 72, para. 204.

59 Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v. Nicaragua) and Construction of a Road in Costa Rica along the San Juan River (Nicaragua v. Costa Rica), Judgment of 16 December 2015, [2015] ICJ Rep. 665, at 706, para. 104. M. A. Fitzmaurice defines EIAs as the ‘very fundamental of contemporary environmental law and the heart of prevention’. See M. A. Fitzmaurice, International Protection of the Environment (2001), at 284.

60 Certain Activities Carried Out by Nicaragua, ibid., at 705, para. 100.

61 Ibid., at 719, para. 146.

62 For the application of the obligation to perform an EIA even when the harm might affect areas beyond the national jurisdiction, see Responsibilities and obligations of States with respect to activities in the Area, Advisory Opinion, supra note 53, at 51, para. 148. The reasoning of the Seabed Disputes Chamber is, however, loose because it used the ICJ’s recognition of the customary obligation in a transboundary context as the legal basis to extend its spatial scope to areas beyond national jurisdiction. However, the existence of a customary obligation in a transboundary context does not necessarily mean that the obligation has the same status in areas beyond national jurisdiction. On the environmental aspects of this advisory opinion see L. Pineschi, ‘The Duty of Environmental Impact Assessment in the First ITLOS Chamber’s Advisory Opinion’, in N. Boschiero et al. (eds.), International Courts and the Development of international Law: Essays in Honour of Tullio Treves (2013), at 425–39.

63 F. Durante argues that Art. III OST has a pleonastic character because when states operate in outer space they continue to operate as members of the international community, i.e., as legal entities whose relations are regulated by international law to the extent that it is compatible with special rules enacted for the space environment. F. Durante, ‘La codificazione dei principi sull’esplorazione e l’utilizzazione dello spazio extra-atmosferico’, in Le droit international à l’heure de sa codification. Etudes en l’honneur de Roberto Ago (1987), vol. II, at 160.

64 Certain activities, supra note 59, Separate Opinion of Judge ad hoc Dugard, at 849, para. 19.

65 Contra, L.-A. Duvic-Paoli keeps the distinction between a preliminary assessment that evaluates whether the planned activity should be subject to an EIA and the EIA itself: L.-A. Duvic-Paoli, The Prevention Principle in International Environmental Law (2018), at 212.

66 In this sense see also Birnie, Boyle and Redgwell, supra note 47, at 171; ‘Almost by definition, ultra-hazardous activities must be carried out through the adoption of measures of “ultra-prevention” of harm.’ T. Scovazzi, supra note 31, at 49.

67 For the qualification of space activities as ultra-hazardous see the ILC Draft Articles on Prevention of Transboundary Harm from Hazardous Activities, para. 4 of the Commentary to Art. 1.

68 Pulp Mills, supra note 45, at 82 and 83, paras. 204–205; see also Certain activities, supra note 59, at 706, para. 104.

69 Certain Activities, supra note 59, Separate opinion of Judge Bhandari, at 801, para. 33.

70 Ibid., at 803, para. 41.

71 Ibid., at 805, paras. 45–46.

72 Pulp Mills, supra note 45, at 79, para. 197.

73 UNCOPUOS Guidelines 2 and 5; IADC Mitigation Guideline 5.2.2. The main causes of fragmentation are currently explosive events due to residual fuel or the batteries on board. Think of the break-up of a Proton launch stage belonging to the Russian Federation in 2007, for example.

74 UNCOPUOS Guideline 1; see also the Long-term sustainability Guideline B.8: ‘Design and operation of space objects regardless of their physical and operational characteristics.’

75 Several strategies, including the shielding of the critical components of a spacecraft, can be adopted to protect a spacecraft from the consequences of orbital debris impacts. See UNCOPUOS Guideline 3.

76 UNCOPUOS Guideline 2; see also 5.2.2 IADC Mitigation Guidelines. Art. 4.1.2 (n. SD-DE-05) of the European Code of Conduct for Space Debris Mitigation is even more detailed and sets a specific break-up probability threshold.

77 In this sense see Statement by the European Space Agency on Space Debris at the 2020 Scientific and Technical Subcommittee (6 February 2020).

78 European Code of Conduct for Space Debris Mitigation Art. 3.3 (no. SD-MM-03).

79 The UK Outer Space Act, for example, requires the licensee to conduct its operations in such a way as to prevent the contamination of outer space or adverse changes to the environment of the Earth. See UK Outer Space Act of 1986, Sec. 5 e) i).

80 In this sense see the Long-term sustainability Guideline B.8, para. 2. On this see S. J. Garber, ‘Incentives for Keeping Space Clean: Orbital Debris and Mitigation Waivers’, (2017) 49 Journal of Space Law 179–202.

81 Certain Activities, supra note 59, at 706, para. 104. International practice leaves little doubt that the EIA must be communicated to potentially affected states. Cf. South China Sea Arbitration (The Republic of Philippines v. The People’s Republic of China), PCA Case Nº 2013-19, at 395–6, paras. 987–991.

82 See the final part of Art. IX OST.

83 Pulp Mills, supra note 45, at 59, para. 115; see also MOX Plant (Ireland v. United Kingdom), Provisional Measures, Order of 3 December 2001, [2001] ITLOS Rep. 95, at 110, para. 84.

84 In this sense see also E. Ruozzi, ‘The Obligation to Undertake an Environmental Assessment in the Jurisprudence of the ICJ: A Principle in Search of Autonomy’, (2017) 8 European Journal of Risk Regulation 158–69, at 169.

85 Ex multis Gorove, supra note 42, at 63–4; M. Williams, ‘Safeguarding Outer Space: On the Road to Debris Mitigation’, in Security in Space: The Next Generation: Conference Report, 31 March-1 April 2008, United Nations Institute for Disarmament Research (UNIDIR) (2008), at 86.

86 N. Mateesco-Matte, ‘Environmental Implications and Responsibilities in the Use of Outer Space’, (1989) 14 Annals of Air & Space Law 419–48, at 430; Gorove, supra note 42, at 63; M. Williams, ibid., at 87; Nelson, supra note 35, at 122–3.

87 K.-H. Böckstiegel, ‘The Settlement of Disputes Regarding Space Activities’, in G. Lafferranderie and D. Crowther (eds.), Outlook on Space Law Over the Next 30 Years (1997), at 237–8.

88 The ICJ recalled the principle that a treaty must not be interpreted in such a way that would render parts of the text redundant or meaningless in Fisheries Jurisdiction (Spain v. Canada), Jurisdiction of the Court, Judgment of 4 December 1998, [1998] ICJ Rep. 432, at 455, para. 52; Application of the International Convention on the Elimination of All Forms of Racial Discrimination (Georgia v. Russian Federation), Preliminary Objections, Judgment of 1 April 2011, [2011] ICJ Rep. 70, at 125–6, paras. 133–134.

89 See Espoo Convention, Implementation Committee’s findings and recommendations further to a submission by Romania regarding Ukraine, Meeting of the Parties to the Convention on Environmental Impact Assessment in a Transboundary Context, ECE/MP.EIA/10 (2008), Annex 1, at 91, para. 53.

90 On the concept of self-interpretation see G. Abi-Saab, ‘General Cours’, in Recueil des cours (1987), vol. VII, at 223; R. Kolb, Interprétation et création du droit international (2006), at 286; A. Tanzi, Introduzione al diritto internazionale contemporaneo (2019), at 235–6.

91 VCLT Arts. 26, 31.

92 Abi-Saab, supra note 90, at 226.

93 On the possibility for any state to invoke responsibility in the case of a breach of an obligation to protect the environment of international space see R. L. Johnstone, Offshore Oil and Gas Development in the Arctic under International Law (2015), at 222–5; G. Gaja, ‘States having an Interest in Compliance with the Obligation Breached’, in J. Crawford, A. Pellet and S. Olleson (eds.), The Law of International Responsibility (2010), at 961; Scovazzi, supra note 31, at 62–3. In addition, the interest at stake to maintain the freedom of exploration and use of outer space is apparently not a particular interest of a state party but of the international community as a whole. Therefore, the obligation to avoid harmful contamination is due to all states. See V. Kopal, Outer Space as a Global Common, in Proceedings of the 40^th Colloquium on the Law of Outer Space, 1997, at 108–18.

94 L. Viikari even argues that such consultations might be necessary before any future launch of a space object because space objects always tend to turn into or produce some debris that may gravely interfere with the space activities of all states: Viikari, supra note 8, at 60. However, this thesis really seems to go too far.

95 Lac Lanoux Arbitration (France v. Spain), 16 November 1957, (1957) 12 RIAA 281, at 307.

96 The doctrinal debate on the lawfulness of the military use of outer space is vast. See, ex multis, M. Gestri, ‘Portata e limiti del principio dell’uso pacifico nel diritto dello spazio’, in F. Francioni and F. Pocar, Il regime internazionale dello spazio (1993), at 51–78; L. Condorelli and Z. Mériboute, ‘Some Remarks on the State of International Law Concerning Military Activities in Outer Space’, (1985) Italian Yearbook of International Law, at 3.

97 For the arguments supporting the ‘non-military’ interpretation see the passionate pages in G. Gal, Space Law (1969), at 164–72.

98 See UNCOPUOS Guideline 4; IADC Mitigation Guidelines 5.2.3. The European Code of Conduct is even more trenchant: ‘Intentional destruction of a space system or any of its parts in orbit is prohibited.’, Art. 4.1.2 (n. SD-DE-04).

99 Report of the Legal Subcommittee, supra note 8, at 26, para. 184.

100 2019 UNCOPUOS Report, supra note 4, at 30, para. 230.

101 In 2019, India destroyed one of its own satellites that was in low-earth orbit. The Indian ASAT test increased the number of states in possession of this capability to four. In 2021, Russia destroyed one of its inactive satellites and created over 1,500 pieces of debris.

102 One might think of the ‘necessary’ destruction of a space object posing a potential danger to the population on the ground.

103 In this sense see also Pedrazzi, supra note 30, at 117.

104 On the lawfulness of anti-satellite weapon testing see also S. Marchisio, ‘Gli usi militari dello spazio: scenari internazionali e tavoli negoziali’, in S. Marchisio and U. Montuoro, Lo spazio cyber e cosmico (2019), at 159.

105 The applicant states argued that France had been infringing the fundamental principle of freedom of the high seas by imposing a no-fly and no-shipping zone in the area where the tests were taking place. The parallel with the freedom to explore and use outer space is quite evident. See the Nuclear Tests Case (Australia v. France), Application Instituting Proceedings, 9 May 1973, at 51, para. 49; Nuclear Tests case (New Zealand v. France), Application Instituting Proceedings, 9 May 1973, at 8, para. 28. For an overview of these cases see A. Pietrobon, ‘Nuclear Powers’ Disarmament Obligation under the Treaty on the Non-Proliferation of Nuclear Weapons and the Comprehensive Nuclear Test Ban Treaty’, (2014) 27 LJIL 169–88, at 171–2.

106 Request for an Examination of the Situation in Accordance with Paragraph 63 of the Court’s Judgment of 20 December 1974 in the Nuclear Tests (New Zealand v. France) case, Order of 22 September 1995, [1995] ICJ Rep. 288.

107 Ibid., at 306, para. 63.

108 Ibid., para. 64.

109 Request for an Examination, supra note 106, Application Instituting Proceedings, 21 August 1995, at 36–40, paras. 73–82.

110 For this reason, it makes no sense to emphasize the need to submit the intentional destruction of space objects to criteria and procedures (see 2019 UNCOPUOS Report, supra note 4, at 30, para. 230). They are already there. The point instead is to make them more specific and procedurally stringent.

111 See supra Section 6.

112 In this sense see also M. Mineiro, ‘The United States and the Legality of Outer Space Weaponization: A Proposal for Greater Transparency and a Dispute Resolution Mechanism’, (2008) 33 Annals of Air & Space Law 441–68, at 456; B. L. Hart, ‘Anti-Satellite Weapons: Threats, Laws and the Uncertain Future of Space’, (2008) 33 Annals of Air & Space Law 344–81, at 378–9; S. G. Gunasekara, ‘Mutually Assured Destruction: Space Weapons, Orbital Debris, and the Deterrence Theory for Environmental Sustainability’, (2012) 37 Air and Space Law 141–164, at 160–1.

113 See UNCOPUOS Guideline 4; IADC Mitigation Guideline no. 5.2.3.

114 For definitions of LEO and GEO see IADC Guideline 3.3.2(1) and 3.3.2(2).

115 In order to facilitate consensus, the UNCOPUOS Guidelines leave out many technical aspects in comparison to the IADC Guidelines. They do not speak of de-orbiting (for the definition of ‘de-orbit,’ see IADC Guideline 3.4.2) but generally of removal, and also the so-called 25- year rule is not made explicit: ‘25 years [is found] to be a reasonable and appropriate lifetime limit’. IADC Guideline 5.3.2.

116 On re-entry see also IADC Space Debris Mitigation Guideline 5.3.2; Art. 5.4 European Code of Conduct.

117 In similar terms see the long-term sustainability Guideline A.4, para. 6.

118 See also the ITU Recommendation, supra note 52.

119 See infra in the text.

120 Small satellites currently lack on-board propulsion systems and are therefore unable to voluntarily change their trajectories or perform de-orbiting procedures. They are launched piggyback and only the state procuring the launch of the primary payload is able to select the destination orbit. Technological development will enable these technical obstacles to be overcome because launch vehicles dedicated to small satellites will soon be available. Therefore, it will be possible to plan their injection into an orbit from which natural decay would be possible. On the legal challenges posed by small (and micro) satellites see P. Rosher and A. Shaw, ‘Micro Satellites: The Smaller the Satellites, the Bigger the Challenges?’, (2016) 41 Air and Space Law 311–28.

121 Art. 40 of the Decree on Technical Regulation issued on 31 March 2011 pursuant to Act no. 2009-643 of 9 June 2009.

122 All these aspects, namely the existence of a minimum de-orbiting capability and the characteristic of the selected orbit, should be considered in the EIA. See supra Section 6.

123 G. Chung suggests that legal control and jurisdiction over registered space objects cease to exist when there is an ‘expressed’ or ‘implied’ act of abandonment, with the consequence that other states could unilaterally remove those objects: G. Chung, ‘Jurisdiction and Control Aspects of Space Debris Removal’, in A. Froehlich (ed.), Space Security and Legal Aspects of Active Debris Removal (2019), at 41. Caution should nonetheless be exercised before drawing the conclusion that a space object is a res derelicta from an ‘implied’ act of abandonment. This option could easily lead to abuse.

124 The lawfulness of keeping non-functional satellites in orbit has therefore been questioned by a number of eminent space law scholars. M. Williams, Space Debris and International Law, Proceedings of the 38^th Colloquium on the Law of Outer Space, 1995, at 66: ‘it is to be wondered whether inactive satellites are complying with the requirements of Article I of the 1967 Space Treaty, particularly the ‘benefit and interest of all countries’ and ‘freedom of scientific investigation’. See also IAA Cosmic Study, Space Debris Environment Remediation, 2011, at 63.

125 In the sense that a customary norm obliging to de-orbit no longer functional objects already exists: Martin, supra note 25, at 35–6.

126 The expression ‘paper satellites’ refers to the practice of registering satellites without actually launching them, merely informed by an intention to hog valuable space resources for future purposes. The ITU promulgated intrusive measures to combat this gross subversion of the ITU registration procedure, such as the cancellation of an unused entry. Non-functional satellites are likewise a waste of valuable resources. They serve no other function but to deprive access to space by other users.

127 Agreement on the Rescue of Astronauts, the Return of Astronauts and the Return of Objects Launched into Outer Space, UN Doc. A/RES/2345(XXII) (1967). As of 1 January 2020, it is binding on 98 states.

128 Emphasis added.

129 See supra note 93.

130 H. DeSaussure goes even farther and focuses on the due regard principle contained in Article IX and on an analogy with derelicts at sea to derive a right for other states to remove a threatening space object: H. De Saussure, ‘An International Right to Reorbit Earth Threatening Satellites’, (1978) 3 AASL 383–94, at 390–4.

131 UNCOPUOS Guideline 6; see also Long-term sustainability Guideline B.9 and D.2 para. 4.

132 On the need for a specific provision with this purpose see also Pedrazzi, supra note 30, at 117. On the need to strengthen the non-binding recommendation that advises ITU members to remove their disused satellites from orbit at the end of their lifetimes into a binding enforceable obligation see Man, supra note 28, at 234.

133 See also the detailed 2007 Nairobi International Convention on the Removal of Wrecks.