2. Territorial sovereignty under general public international law

Article III OST stipulates that ‘States Parties to the Treaty shall carry on activities in the exploration and use of outer space … in accordance with international law’. Admittedly, this provision clearly suffers from redundancy since international law governs state activities either way, wherever they take place without there being any need for a treaty provision to that effect.Footnote ⁵ Be that as it may, this reaffirmation is in any case desirable for rather obvious reasons.Footnote ⁶

It has been submitted that the DNA of the whole body of the laws that govern state activities in a given geographically defined area is more or less prejudiced by the existence or the absence of territorial sovereignty therein.Footnote ⁷ Therefore, as regards the territorial status of outer space lato sensu,Footnote ⁸ it is first appropriate to provide a summary of the rules relevant to the acquisition of sovereignty therein. Territorial sovereignty presupposes a valid title over the respective territory.Footnote ⁹ Customary international law recognizes five particular modes of acquisition of title over territory: occupation (i.e. occupation of terra nullius), prescription (i.e. usucapio), cession, accretion, and conquest.Footnote ¹⁰ Notably, only occupation and accretion are original modes of acquisition, since all the others logically imply the existence of a previous sovereign, being thus derivative.Footnote ¹¹ Moreover, at least theoretically, all titles over any given ‘portion of the surface of the globe’Footnote ¹² are established on the assumption that an original title based on occupation had been effective at some point in time. In other words, occupation is the only conceivable mode of sovereignty acquisition over any given fragment of territory which was never before subject to the supreme authority of any sovereign.Footnote ¹³

With particular reference to occupation as an original mode of territory acquisition, the following observations would presumably suffice for the purposes of this article. It is a well-established general principle of law that occupation involves two elements that must be cumulatively present in any given case. Accordingly, an objective (i.e. continuous and peaceful effective control over the territory, or corpus occupandi) and a subjective element (i.e. the intention to effectively control the territory as a sovereign, or animus occupandi) must be established. With regard to the quality and the quantity of the sovereign activities (effectivités) needed for the establishment of corpus occupandi, it has been settled in theory that relative and flexible criteria should apply;Footnote ¹⁴ indeed the amount and the nature of the effectivités required depend both on the particularities of the territoryFootnote ¹⁵ (e.g. remoteness, geomorphology) under occupation and on the quantity and quality of the competing sovereign activities of other states over the same fragment of territory.Footnote ¹⁶

However, it has been authoritatively submitted that the relativity of the threshold required to be reached by the effectivités in order to be considered as exercise of effective control, and thus as amounting to corpus occupandi, has as its limit an ‘absolute minimum requirement’.Footnote ¹⁷ In extraordinary cases where the remoteness and the hostility of the environment are extreme, this ‘absolute minimum’ would apply. Subsequently, nothing less than the exercise of those activities that are objectively sufficient to render the territory under the ‘absolute and undisputed disposition’ of the claimant state would always be required.Footnote ¹⁸ Consequently, the merit of the submission that the effectivités required for a valid assertion of effective control ‘may in certain rare circumstances be little more than symbolic’ can presumably be questioned.Footnote ¹⁹

Last, ‘activities by private persons cannot be seen as effectivités if they do not take place on the basis of official regulations or under governmental authority’.Footnote ²⁰ Of course, activities à titre de souverain (i.e. de jure imperii) performed by state organs in the exercise of their duties as well as acts of private individuals attributable to a state under the customary international law of attribution should be regarded as effectivités.

Another question that needs to be answered at this point is which areas in particular may be at all subject to occupation. According to the International Court of Justice (ICJ), ‘it was a cardinal condition of a valid “occupation” that the territory should be terra nullius – a territory belonging to no-one – at the time of the act alleged to constitute the “occupation”’.Footnote ²¹ Notably, the notion of terra nullius encompasses both areas that were never subject to a sovereign's authority and areas that have been abandoned with the sovereign's intention to forgo sovereignty.Footnote ²² However, it is of particular relevance to the subject of this article that areas with no reference whatsoever to terra firma, and thus where no state may exercise effectivités that would reach even the minimum threshold required for the establishment of effective control thereto, cannot qualify as terrae nullius.

More concretely, with respect to such areas, even the minimum threshold required in order for the respective effectivités to amount to corpus occupandi cannot possibly be reached. Hence, sovereignty thereto cannot be acquired by means of occupation.Footnote ²³ Indeed, it has been established that there is a distinction between areas under no sovereign rule where the exercise of effective control (corpus occupandi) is physically and legally possible and areas under no sovereign rule where, however, sovereign activities are impossible physically and/or legally.Footnote ²⁴ Areas belonging to the former category can be qualified as terrae nullius. Conversely, areas unsusceptible to a minimum degree of effective control, such as the high seas, have ipso facto the status of res communes omnium.Footnote ²⁵ At this point it should be noted that many commentators tend to use the term res extra commercium interchangeably with that of res communis omnium in order to refer to the exact same category of territories. Arguably, however, to the extent that both terms are used in order to encompass areas whose effective control is impossible physically and/or legally, this terminological pluralism lacks any practical significance.Footnote ²⁶

As regards the vast territories of the outer space lato sensu, the question of its territorial status can be answered only with reference to the permissibility or even the feasibility of occupation, as the only conceivable mode of territory acquisition that may be relevant in outer space. Put differently, it would be superfluous to examine whether or not outer space is subject to territorial sovereignty by means other than occupation. More accurately, as a first stage it is appropriate to conclude whether occupation in outer space is feasible and as a second whether such occupation would be permissible under standing international law.

3. The territorial status of outer space before the entry into force of the Outer Space Treaty

It has been extensively supported that even before the entry into force of the Outer Space Treaty, outer space stricto sensu, by direct analogy to the high seas, had been res communis omnium (or if one prefers, res extra commercium) and not terra nullius, since the exercise of effective control over it is physically impossible due to ‘basic astronomical facts’.Footnote ²⁷ Nevertheless, others who have disregarded the aforementioned assertions have concluded the opposite.Footnote ²⁸ Therefore, it has accurately been submitted that the outer space stricto sensu has never been amenable to occupation and thus no state could possibly acquire sovereignty thereto. By contrast, many commentators have concluded that, unlike outer space stricto sensu, celestial bodies were terrae nullius until the entry into force of the Outer Space Treaty.Footnote ²⁹ However, such a position fails to clarify the reasons why celestial bodies are, supposedly, more susceptible to effective control than outer space stricto sensu, especially if one takes into account that the environment of most celestial bodies, at least in our solar system, is actually more hostile to human beings than that of the void space between them.Footnote ³⁰ Hence, it is submitted that the outer space lato sensu has never been susceptible to occupation and thus no state could possibly acquire sovereignty thereto even in the absence of the non-appropriation principle as promulgated in the Outer Space Treaty.Footnote ³¹

Reasonably, however, the practical relevance of this clarification could be questioned in view of the universal resonance of the non-appropriation principle, which has manifestly and explicitly eliminated the acquisition of sovereignty in outer space.Footnote ³² It is certainly true that even without Article II OST, no fragment of outer space lato sensu could be acquired by any state as a matter of international law, simply because no occupation can be effective therein due to the impossibility of the establishment of corpus occupandi.Footnote ³³ Indeed, the performance of the effectivités necessary to ensure any state's ‘absolute and undisputed disposition’ over a celestial body or a portion of outer space stricto sensu has been and is expected to remain for at least a few more decades technologically unfeasible. Thus, whatever the nature of the effectivités exercised in outer space, they could not satisfy the minimum threshold required under international law in order for them to amount to effective control.Footnote ³⁴ Arguably, the argumentation demonstrated above excludes both the possibility of territory acquisition in outer space within a timeframe starting from the immemorial and ending at some uncertain point in the future; this would be valid even in the absence of Article II OST. This is particularly important if one considers that certain states have already denied that they are bound by the non-appropriation principle as a rule of customary international law.

Indisputably, there will be a day when states will have the means to effectively control at least parts of outer space. It is hoped that by the day when the occupation and thus the acquisition of sovereignty in outer space is not legally impermissible as materially unfeasible, it will continue, however, to be materially unfeasible as legally impermissible. To this end, states have taken the decisive step as early as 1967 by adopting the non-appropriation principle envisaged in Article II OST.

4. The territorial status of outer space after the entry into force of the Outer Space Treaty

Article II of the Outer Space Treaty stipulates that ‘[o]uter space, including the Moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means’. Further, Article 11(2) of the 1979 Agreement Governing the Activities of States on the Moon and Other Celestial BodiesFootnote ³⁵ (hereinafter ‘the Moon Agreement’ or ‘MA’) simply reiterates the non-appropriation principle with respect to the celestial bodies within the solar system.Footnote ³⁶ Celestial bodies outside the solar system fall, however, within the scope of Article II OST.

In order to properly indicate the rights and the duties that the state parties to the aforementioned instruments have undertaken, Article II of the Outer Space Treaty must be interpreted in accordance with the customary rules of interpretation reflected in Articles 31–3 VCLT.Footnote ³⁷ First, it must be observed that OST prohibits ‘national appropriation by means of use or occupation, or by any other means,’ in outer space and no more than that.Footnote ³⁸ As concerns the content of the term ‘national appropriation’, it has to be sought ‘in accordance with the ordinary meaning to be given to the terms … in [its] context and in the light of its object and purpose’Footnote ³⁹ of the OST. In this respect, the ordinary meaning of the word ‘appropriation’Footnote ⁴⁰ suggests that there is no doubt that Article II OST prohibits the acquisition of territorial sovereignty over any part of outer space lato sensu.Footnote ⁴¹ Notably, the drafters of the Outer Space Treaty added the phrase ‘by means of use or occupation, or by any other means,’ in order to eliminate any possible mode of territory acquisition in outer space.Footnote ⁴² It must be also noted that there is a general consensus on the fact that Article II OST dictates just the prohibition of the exercise of territorial sovereignty in outer space and not the abolishment of any other sovereign right that states may exercise under international law, with respect to their activities in outer space.Footnote ⁴³ Besides, the application of the interpretation principle expressio unius est exclusio alterius to Article II OST would confirm the aforementioned submission.Footnote ⁴⁴ However, it has been accurately submitted that, consistent with the so-called Lotus principle, the major difference between the exercise of a state's sovereign rights within its territory and the exercise thereof in an area not subject to its territorial sovereignty is that in the former instance whatever is not prohibited by international law is permissible whereas in the latter the exact opposite is true.Footnote ⁴⁵

Therefore, the adoption of the non-appropriation principle as envisaged in Article II OST and reiterated in Article 11(2) of the MA reaffirmed the status of outer space and its component parts under general international law as being res communis omnium, i.e. unsusceptible to forming a part of any state's territory.Footnote ⁴⁶ It is, furthermore, commonly accepted that the non-appropriation principle has reached the status of customary international law, due to the virtually consistent practice of states not to claim sovereignty over any fragment of outer space, accompanied by opinio juris sive necessitatis.Footnote ⁴⁷

Hopefully, the forthcoming paragraphs will elucidate two particular aspects of the non-appropriation principle, namely the legal essence of the res communis omnium regime with reference to the exploitation of spatial natural resources and the application of the non-appropriation principle to private individuals.

5. The exploitation of spatial resources in a res communis omnium regime

With regard to the content of the res communis omnium regime of outer space lato sensu reaffirmed by the Outer Space Treaty, it is first appropriate to address certain generic characteristics thereof. Ever since the formulation of legal principles governing the activities of states on the high seas, it is generally accepted in legal theory that the pillars of any res communis omnium regime are the following: in Roman law, things (res) classified as common to all were not susceptible to private ownership (dominium plenum) and therefore no citizen was entitled to exclude others from the full enjoyment of the res communis omnium.Footnote ⁴⁸ In this sense, any citizen has the right to use and exploit it to the extent that does not impair the respective freedoms of others. Accordingly, if properly applied in the domain of public international law, the aforementioned principles essentially confer a right on each particular state to freely use and exploit areas subject to a res communis omnium regime, with due regard to the interests of other states.Footnote ⁴⁹ In view of the very nature of the res communis omnium regime, it has been accurately submitted that its essence is merely founded on a perception of individualism rather on a community-orientated basis. The merit of this approach is indeed enhanced especially if one takes into account the uneven level of development between states, which ultimately turns the enjoyment of communal resources to a de facto prerogative of the technologically advanced states.Footnote ⁵⁰

At this point it should be observed that the notion of res communis omnium must not be confused with that of res communis humanitatis which is the primary theoretical foundation for the introduction of the common heritage of mankind (CHM) architecture in international law.Footnote ⁵¹ According to a concise overview of the pillars supporting any CHM structure in international law,

It is apparent that the status of res communis humanitatis cannot possibly be conferred on an area ipso facto, i.e. solely by virtue of its natural characteristics, as it is certainly the case as regards the status of res communis omnium. As concerns international space law, the Moon and the celestial bodies of our solar system have been formally subjected to a res communis humanitatis regime, pursuant to Article 11(1) of the Moon Agreement which converted the celestial bodies falling with its scope from rei communis omnium into rei communis humanitatis.Footnote ⁵³ Of course, this conversion has a legal effect only vis-à-vis state parties to the Moon Agreement.Footnote ⁵⁴ However, as is obvious from the aforementioned observations, the very conception of CHM dictates that its materialization in legal terms presupposes the establishment of a specific conventional framework whose functions would activate the CHM mechanism. This is evident from the wording of the aforementioned provision, which stipulates that the CHM doctrine ‘finds its expression in the provisions of this Agreement, in particular in paragraph 5 of this article’, by virtue of which the state parties to the Agreement undertake to establish an international regime ‘to govern the exploitation of the natural resources of the Moon as such exploitation is about to become feasible’.Footnote ⁵⁵ Indisputably, the Moon Agreement failed to introduce such a framework.Footnote ⁵⁶ This fact, in conjunction with the absence of any provision that would impose a moratorium on the exploitation of natural resources in the celestial bodies of the solar system until the establishment of a workable CHM framework, leads to the conclusion that states are free to exploit spatial natural resources, without prejudice, however, to the provisions of the Outer Space Treaty.Footnote ⁵⁷

Hence, it would be appropriate to argue that even vis-à-vis the state parties to the Moon Agreement, the conversion of the celestial bodies of the solar system into rei communis humanitatis is at best only a nominal one, since the the core provisions of the Agreement have been accurately characterized as pactum de negotiando.Footnote ⁵⁸ In fact, the res communis omnium regime remains effective in its entirety, however desirable the consolidation of the CHM principle would have been.

This article submits, however, that the adoption of a CHM regime and its materialization through the functions of an authority structured in the model of the International Seabed Authority is, inevitably, the only solution that would guarantee the equitable sharing of the universe's wealth.Footnote ⁵⁹

6. The exploitation of spatial resources under Article II of the Outer Space Treaty

Focusing on Article II of the OST for the purposes of clarifying the particular features of the res communis omnium regime in outer space, one could not but notice that the drafters of the Treaty were silent on a series of issues. In particular, it is not stipulated expressis verbis that the principle of non-appropriation of celestial bodies applies with respect both to the surface and to the subsoil thereof. In this regard the recent jurisprudence of the ICJ on the interpretation of generic terms such as ‘outer space’ would presumably dispel any doubts. Indeed, in 2009 the Court in its judgment delivered on the Case Concerning the Dispute Regarding Navigational and Related Rights reaffirmed that generic terms denote any particular element comprised with in the concept of the former.Footnote ⁶⁰ This is particularly true when the likelihood of evolvement is involved as regards the context in which the respective term is used.Footnote ⁶¹ Similarly, the ICJ on the occasion of the interpretation of another generic term, that of ‘territorial status’, stressed that ‘the expression “the territorial status of Greece” was used … as a generic term denoting any matters comprised within the concept of territorial status under general international law’.Footnote ⁶² Obviously, the Court's assertions mentioned above are relevant for the interpretation of the term ‘outer space’ in Article II of the OST. In any case, Article 11(3) of the Moon Agreement refers specifically to ‘the surface … the subsurface’ of the celestial bodies of the solar system and to ‘any part thereof or natural resources’ in order reaffirm the non-appropriation principle. Understandably, this clarification has been welcomed by many commentators.Footnote ⁶³

Another omission of the drafters of Article II of the Outer Space Treaty that has caused heated debate in the literature is the absence of any reference to the permissibility of the exploitation of natural resources in outer space lato sensu. In other words, the Outer Space Treaty has failed to provide a definite answer to the question whether the exclusion of acquisition of territorial sovereignty over any area in outer space has any impact whatsoever on the rights of states and by extension of their nationals to ‘harvest’ the natural resources contained therein for exclusive use.Footnote ⁶⁴ It has been submitted that for the systematic purposes of such an analysis a distinction should be made between exhaustible (e.g. minerals) and inexhaustible (e.g. cosmic rays) spatial resources. Further, it has not been contested that the exploitation of the latter could hardly be prohibited under Article II of the OST, even if one assumes that this provision indeed prohibits the exploitation of exhaustible spatial resources.Footnote ⁶⁵ In general, those who favour an interpretation of Article II of the OST in a manner that would render the appropriation of natural resources in outer space impermissible have failed to base their argumentation on any commendable legal ground capable of distinguishing the exercise of territorial sovereignty over a given area from the sovereign right to exploit the natural resources of that area. However, this distinction has been very well conceivable in international law and in particular in the law of the sea since the beginning of the seventeenth century.Footnote ⁶⁶ Moreover, it has been wrongly assumed that Article II of the OST establishes a res communis humanitatis and not a res communis omnium regime and therefore no state or its nationals may appropriate the natural resources of outer space lato sensu.Footnote ⁶⁷ More specifically, A. Cocca, the instigator of the CHM principle envisaged in the Moon Agreement, has asserted that

However, the prevailing opinion on the subject has been suggesting since 1970 that Article II of the OST only prohibits the incorporation of any area of outer space lato sensu in the sovereign territory of any state and not the exercise of other sovereign rights such as the freedom to exploit spatial natural resources. Accordingly, provided that the principle res accessoria sequitur principalem does not apply in outer space,Footnote ⁶⁹ the establishment of permanent space stations on the surface of celestial bodies is permissible since it would not amount to appropriation of the soil and subsoil upon which such stations would be built.Footnote ⁷⁰ More concretely, most of the members of the International Law Association (ILA) Space Law Committee argued in 1970 that ‘by analogy to the rules underlying the freedom of the seas, the appropriation of natural resources merely formed part of the freedom of exploration and use of outer space’.Footnote ⁷¹ Indeed, it has been submitted that ‘the ability of a State to exercise certain rights over areas without claiming absolute title had repeatedly been demonstrated on Earth, in particular in so far as the high seas are concerned’.Footnote ⁷² Accordingly, an interpretation of Article II of the OST with due regard to its contextFootnote ⁷³ and in particular to Article I of the OST, which stipulates, inter alia, that ‘[o]uter space including the Moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law’, would leave no doubt that the exploitation of spatial resources is an inalienable sovereign right of every state not impaired by the non-appropriation principle. Additionally, the freedom of the high seas as a norm of customary international law can be qualified as a relevant rule of international law between states in the meaning of Article 31 of the VCLT and thus it may be invoked in support of the prevailing interpretation of the Outer Space Treaty. Actually, Articles I and II of the OST must be interpreted in conjunction in order for the proclamation that outer space is the province of all mankind to acquire legal essence.Footnote ⁷⁴ Of course, the limit to each state's freedom to use outer space is the de facto exclusion of other states from their own freedoms. Indeed, such an exclusion would amount to the exercise of territorial sovereignty and would thus be prohibited.

This article, however, submits that it is rather unlikely that, if applied to outer space, the ‘freedom of the seas’ paradigm will serve the interests of the majority of Earth's population. Indeed, a res communis omnium regime is inherently favourable towards a laissez-faire approach to space exploitation since it allows states to individually harvest the ‘high frontier’.Footnote ⁷⁵ As a result, only a few societies will eventually benefit from the universe's wealth, through the means that are soon to be at the disposal of a handful of technologically advanced space-faring nations. The rest will have to settle with a freedom too expensive to exercise.Footnote ⁷⁶ By contrast, the res communis humanitatis doctrine reflects an entirely different perception.Footnote ⁷⁷ Instead of creating a free-market economy framework for resource exploitation, it focuses on the establishment of an international legal structure whereby the appropriation of natural resources of any kind cannot be conceived,Footnote ⁷⁸ while an international authority is competent for the management of any exploitative activity. The benefits of such activities are equally distributed to all states.Footnote ⁷⁹ Apparently, the CHM doctrine is ‘inconsistent with the concept of profit’.Footnote ⁸⁰ It is, in other words, obvious that ‘the essence of the CHM theory is to assist those States that have inadequate means to enjoy the benefits acquired by the commons’.Footnote ⁸¹

To summarize, the spatium liberum doctrine, which at present is the law, is undoubtedly less advanced than res communis humanitatis as the former reflects the socioeconomic relations of a global community as old as the Industrial Revolution whereas the latter seems to reflect a radically different economic paradigm, which will hopefully emerge at some point in the near future. In other words, it is inevitable that the current legal superstructure will be superseded by another, more suitable to the new socioeconomic structure, capable of expressing the interests of mankind as a whole. In this respect, the experience of the law of the sea is invaluable, for the freedom of the seas has become subject to restrictions:

7. The prohibition of the exercise of dominium plenum by private individuals over any fragment of outer space

Another issue not explicitly addressed in Article II of the Outer Space Treaty is that of the elimination of private ownership in outer space lato sensu. More concretely, the Treaty does not spell out an explicit prohibition of the exercise of dominium plenum over spatial territories by private individuals.Footnote ⁸³ However, as will be demonstrated infra, the prohibition of the acquisition of private property therein is so elementary in normative terms that it is hardly surprising that the drafters of the Treaty did not proclaimed it expressis verbis.

It is a fact that various businessmen, supported by the opinions of few scholars,Footnote ⁸⁴ have taken advantage of the aforementioned omission and have established a flourishing spatial real-estate industry, to the detriment of the interests of the international community.Footnote ⁸⁵ However, the ILA as early as 1970 had stated that with respect to outer space stricto sensu ‘the draftsmen of the principle of non-appropriation never intended this principle to be circumvented by allowing private entities to appropriate areas of the Moon and other celestial bodies’.Footnote ⁸⁶ Additionally, as regards outer space lato sensu, extensive scholarly writing has been produced in defence of the non-appropriation principle. Accordingly, some of the arguments that have been submitted will be presented below.

It is a doctrinal principle of any legal theory that the term ‘right’ acquires a legal substance only because of its conferment on its beneficiary by a certain legal order.Footnote ⁸⁷ Accordingly, the conferment of private property rights over any portion of a given territory presupposes that the state which confers the proprietary title is entitled to exclude other sovereigns from doing so. In other words, it presupposes supreme authority over that portion of territory, i.e. territorial sovereignty.Footnote ⁸⁸ Therefore, as a matter of international law, the appropriation of any part of outer space lato sensu by private individuals is precluded by Article II of the Outer Space Treaty. Hence, any state that confers proprietary rights in outer space would commit an internationally wrongful act, since nemo plus juris transfere potest, quam ipse habet.

Another argument that has also been submitted is based on the interpretation of Article II of the OST in conjunction with Article VI thereof, which stipulates, inter alia, that ‘[t]he activities of non-governmental entities in outer space … shall require authorization … by the appropriate State Party to the Treaty’. Therefore, a private entity may not engage in any activity in outer space, including activities that involve the establishment or the exercise of proprietary rights, without having been authorized by the appropriate state for that purpose. Moreover, as has already been demonstrated in this article,Footnote ⁸⁹ activities of private entities can be seen as effectivités, i.e. as sovereign activities of a state towards the acquisition of territorial sovereignty by means of occupation, provided that they take place under the regulations and/or the authority of that state. This would essentially mean that the state that authorizes the appropriation of any part of outer space by a private individual would legally claim that part by means of occupation and thus would fail to observe its obligation under Article II of the OST.Footnote ⁹⁰

8. Defying the cornerstone of international space law: the Bogotà Declaration

Although the ground upon which the non-appropriation principle is based is arguably solid, there have been instances where its very essence has been questioned. Indeed, certain state and non-state actors have defied the predominance of the res communis omnium regime in outer space. The forthcoming lines will address the most significant challenges to the non-appropriation principle.

On 3 December 1976 eight equatorial states, namely Brazil, Ecuador, Colombia, Congo, the Democratic Republic of Congo (then still Zaire), Indonesia, Kenya, and Uganda, signed an international agreement titled ‘Declaration of the First Meeting of Equatorial Countries’, widely known as the Bogotà Declaration (BD).Footnote ⁹¹ Article 1 thereof provides a definition of geostationary earth orbit (GEO or GSO)Footnote ⁹² while declaring it a limited natural resource.Footnote ⁹³ Moreover, Article 2(4) of the Declaration proclaims that GEO ‘is under the sovereignty of the equatorial States’. Consequently, as stipulated in Article 3(e), the equatorial states signing the Declaration conclude that the allocation of satellites in any fragment of the geostationary arc is subject to the sovereign will of the state on whose territory that particular point is located. This effectivité of the state signatories to the Declaration was based on two particular legal arguments aiming to circumvent the non-appropriation principle as applied to outer space stricto sensu. Not surprisingly, the promulgation of the appropriation of GEO triggered its emphatic condemnation by most states.

Article 4(4) of the Declaration provides that

The state signatories therefore purported to take advantage of the fact that the drafters of the Outer Space Treaty were unable to agree upon a definition of outer space. It is certainly true that treaty law does not provide for such a definition.Footnote ⁹⁴ However undesirable the lack of a contractual delimitation between air and outer space might be, this does not mean that international space law does not provide for a delimitation at all. On the contrary, it is submitted that a customary delimitation rule according to which ‘outer space begins at least at the lowest perigee of the orbit of the Earth's artificial satellite, that is, at an altitude of 100–110 kilometers above sea level’Footnote ⁹⁵ has indeed evolved. Indeed, the consistent practice of states for at least 40 years, accompanied by opinio juris, allows the submission of this conclusion.Footnote ⁹⁶ Notably, the ILA resolved in support of this position as early as 1980.Footnote ⁹⁷

Assuming therefore that the equatorial states that have signed the Bogotà Declaration were bound by that rule at the time when they concluded it, it is submitted that they have committed an internationally wrongful act for having breached their obligation not to claim territorial sovereignty over any part of outer space stricto sensu, prescribed by Article II of the OST. In this context an interesting question that could be raised is whether or not the equatorial states that have signed the Bogotà Declaration can be considered as persistent objectors to the aforementioned customary rule. For the purposes of this article, however, this issue cannot possibly be addressed. It suffices to submit that the state signatories to the Declaration are presumably not persistent objectors to the aforementioned delimitation rule, since the period of its crystallization must have ended prior to 1976.Footnote ⁹⁸ In any case, even if the answer is in the affirmative, that would not necessarily mean that the GEO, a spatial zone located way above the limit of 100 kilometres, would fail to fit within the ‘term outer space’, even in its generic meaning.

Another issue worth summarily addressing is the possibility that the Bogotà Declaration is evidence of the existence of a regional customary rule departing from the universal delimitation rule mentioned above. In this respect, it should be borne in mind that even if the merit of such an assertion is endorsed, such a regional custom would be effective only in the relations among the states of the region and could not be invoked against third states.Footnote ⁹⁹

Moreover, reference should be made to the second argument promulgated in the Bogotà Declaration. Article 1(3) thereof states that

In response to that argument it has been submitted that such assertions ‘contradict physical laws. The geostationary orbit does not exist per se. In each concrete case the phenomenon of a geostationary satellite is associated with a definite space object: if there is no object there is no geostationary orbit’.Footnote ¹⁰⁰ Of course, this is not to suggest that in the absence of a space object the territory where GEO may be reached disappears. It simply points out that the presence of a space object is obviously essential for an orbit to exist; territory is one thing and orbit quite another. The aforementioned observation stresses that GEO, like any other orbit, is a physical phenomenon which occurs only in the presence of a space object within a specific fragment of territory in outer space. It also underlines the fundamental distinction that needs to be made between the physical phenomenon (orbit) and the space where it occurs. In other words, it is essential always to distinguish between the territory where GEO can be reached and the orbit itself. Admittedly, the Bogotà Declaration has blurred the distinction between the two.

Indeed, GEO is a type of orbit, i.e. a physical phenomenon, and is not territory. Evidently, no state may exercise territorial sovereignty over GEO since by definition territorial sovereignty may only be exercised over segments of territory and not over physical phenomena. Apparently, however, the sovereign of the territory where a physical phenomenon takes place has the exclusive right to harvest the phenomena that occur in his territory. If no sovereign exists over that territory, no state may preclude other states from enjoying the benefits entailed by the occurrence of the phenomena. Therefore, the declaration made in Article 2(4) of the Bogotà Declaration that ‘the synchronous geostationary orbit … is under the sovereignty of the equatorial states’ is absurd.

While in Article 2(4) of the Bogotà Declaration, the state parties to the Declaration claim sovereignty over GEO, the chapeau of the very same article reads as follows: ‘Sovereignty of Equatorial States over the Corresponding Segments of the Geostationary Orbit’. Besides, Article 3 of the Bogotà Declaration refers to ‘the existence of sovereign rights over segments of geostationary orbit’. It is, therefore, apparent that the drafters of the declaration were somehow confused as regards the distinction between GEO and its corresponding segments. In any case, and since no sovereignty is conceivable over any kind of orbit, the question that needs to be answered is whether the fragments of territory where GEO can be possibly reached may form part of a state's territory. If this was the case, then the sovereign could lawfully preclude other states from utilizing that space in any manner whatsoever, including the placement of space objects into geostationary orbit. The obvious answer is that even in the absence of the gravitational phenomena generated by our planet, the territory where GEO is possible because of the Earth's gravity would still exist as a zone of void space located approximately 35,871 kilometres over the equator. Consequently, by application of the principle of non-appropriation, this territory is a res communis omnium.Footnote ¹⁰¹ The fact that within it a particular physical phenomenon such as GEO may or may not occur is totally irrelevant.

9. Concluding remarks

The preceding paragraphs have hopefully contributed to a more concise understanding of the non-appropriation principle envisaged in Article II of the Outer Space Treaty. This article has attempted to clarify that outer space lato sensu has always been a res communis omnium and therefore it has never been subject to occupation or any other mode of territory acquisition under general public international law. It has been also submitted that the prohibition of the exercise of territorial sovereignty in outer space does not impair the exercise of states’ other inherent sovereign rights thereto. Further, this article purported to stress that the reaffirmation of the status of outer space by the corpus juris spatialis and its standing as customary international law are of critical importance primarily because of the fact that the non-appropriation principle, which constitutes the cardinal norm in international space law, is the cornerstone of the whole legal architecture of the norms that govern the activities of states and thus of private individuals in outer space.

It has to be borne in mind that the contractual recognition of the fact that outer space is unsusceptible to national or private appropriation allowed the orderly development of space activities for more than forty years and has effectively prevented a colonial race in the high frontier. With due regard to this belief, the preceding paragraphs addressed the Bogotà Declaration as the most severe of the few instances where the non-appropriation principle was defied, notwithstanding that the private sector, especially in the United States, has been increasingly involving itself in business projects that pose a direct threat to the Grundnorm of international space law. In this respect, the activities of private entities are well known and due to the lack of adequate space have not been addressed in this article. Moreover, the increasing number of claims raised by private individuals on celestial bodies, including the Sun, must not go unnoticed. Accordingly, the initiatives undertaken by the International Law Association and the International Institute of Space Law in defence of the non-appropriation principle deserve high praise.

It is hoped that efforts to increase awareness of the precise legal status of the vast territories of outer space make some contribution not only to scholarly debates but also to the ever-increasing practice of states that long ago have ceased to be constrained by our planet's gravitational field.