Revista Brasileira de Direito Aeroespacial

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Observing the Earth From Space
in Light of the Principle of Sovereignty

Professor Dr. Maureen Williams (1)        


The observation of the Earth from outer space by remote sensing satellites has always been a highly sensitive topic in the eyes of the international community as has been the question of direct broadcast satellites. This is reflected in the fact that, within the United Nations framework, it was not possible to reach a binding international agreement to govern these matters. A set of Principles was adopted instead, in 1986 and 1982, respectively, which laid down guidelines for these activities. Likewise, the use of nuclear power sources in outer space followed a similar pattern: the treatment of this matter within the world organization culminated with the adoption of a series of Principles in 1992.

In the case of Earth observation by means of space technologies the first hindrance is the confrontation of two traditional principles of International Law, namely the freedom of exploration and use of outer space declared in Article I of the 1967 Space Treaty, and the principle of sovereignty which, when applied to this field, may be seen as the principle of non-intervention in the internal affairs of States or principle of exclusive jurisdiction, enshrined in Article 2.7 of the United Nations Charter. There is yet another confrontation between freedom of information (as applied to the distribution of the collected data) and prior consent of the sensed State. To this one may add the fact that State sovereignty over natural resources has been repeatedly proclaimed by United Nations General Assembly Resolutions.

By way of illustration reference will be made to an episode which took place at the dawn of the space era, in 1960. On May 16th of that year, during a summit meeting celebrated in Paris, Adenauer, Eisenhower, De Gaulle, Krushchev and Macmillan were immersed in vitriolic conversation. At a given moment - according to Macmillan´s Memoirs – Krushchev addressed Eisenhower harshly on the issue of the flight of the American U2 which had been shot down shortly before over Soviet territory, with pilot Guy Powers on board. At his point De Gaulle intervened observing that the artificial satellites launched by the USSR since 1957 were just as responsible for spying activities as the U2. To which Krushchev answered that it was not so because Sputniks did not carry cameras on board (2).

This is, precisely, what remote sensing is all about. It implies the collection of information by means of space technologies.

Back in 1960, the answers given at the Paris summit were not altogether wrong. There was a great deal of confusion in those days concerning the legal status of outer space in the absence of an agreement which - as later embodied in Article I of the 1967 Space Treaty – proclaimed the freedom of exploration and use of the new regions reached by man .

Nowadays the panorama is infinitely more complex and perhaps slightly clearer from the legal point of view. This is so in spite of States not having yet agreed on the point at which they may extend their sovereign rights in space and at what height the régime of freedom of exploration and use enshrined in the 1967 Treaty began to apply (3). In other words, if a photograph is taken from an aircraft over the territory of a third State the latter would have every right to object to the activity on the grounds that his sovereign rights were being affected. It should be borne in mind that, until the beginning of the space age, the territory of a State was considered its castle (4) - indeed inaccessible . It was seen as something like an ivory tower.

As Isidoro Ruiz Moreno - Argentine international lawyer of great renown - had observed (5) at the outset of the space era, behind the idea of sovereignty the process of unification of the whole international community was being hindered. The underlying idea then was to consider States as absolute sovereigns, both within and outside their national boundaries.

However, it is now valid to doubt whether a State - within the present international context – is absolutely free to accept whatever it pleases and to invoke the principle of self-determination within the limits of its own will.

Ruiz Moreno believes that sovereignty has never been absolute, not even in the time of the most powerful monarchs. If we go back in history to the days of Francisco de Vitoria, the attitude of this Jesuit scholar calls our attention. It was the time when Charles V was King of Spain and Emperor of Germany, and the Pope had bestowed upon him the right to conquer America. Vitoria confronted both sovereigns, the Pope and the Emperor, using his talent as only weapon. He questioned the unlimited right of the Emperor to conduct the external relations of his realm and also conditioned the way in which he should treat his subjects. Vitoria, at the same time, questioned the Pope´s authority to grant the newly discovered territories in America (6).

It is indisputable that, in the present world, facts are largely overriding the Law. It is doubtless that a photograph taken from outer space, thousands of kilometers away from the Earth surface, is much clearer and precise than that same photograph taken from an aircraft in airspace, in other words, in an area subjected to State sovereignty. This leads to the paradox that an activity will be legitimate or otherwise depending on the distance it is taken from.

For this reason it is recommendable for lawyers and scientists to work together on the basis of an interdisciplinary approach, in order to provide realistic and viable solutions likely to be accepted by the international community. As will be seen later, this is an area in which Argentina and Brazil could move ahead within the framework of Mercosur.

In the first place, it should be borne in mind that remote sensing, just as any other technology is, in itself, totally neutral. It is neither bad nor good. It all depends on the use it is given.

Therefore, it is important to distinguish between Earth observation, in itself, and the manipulation to which the collected data might be subjected. In the first case, the mere act of taking a photograph is altogether legitimate pursuant to the terms of the 1967 Space Treaty - presently in force among almost one hundred States. However so, it may be validly held that most of its provisions are part of today’s customary international law. In the second assumption, when it comes to the distribution of the collected data, a number of problems are raised. When the information falls into the hands of only one State, or a small group of States, concerning, inter alia, the state of crops, or the sanitary conditions of cattle of a third State, this would allow the former to control the market to the detriment of the products of the third State in question.

The complexity of this problem, particularly from the political angle, accounts for the fact that, at the global level, it was not possible to go beyond the United Nations adoption, in 1986, of a set of Principles on Remote Sensing to reach a binding international instrument as was the case in other areas of the law of outer space resulting in the Astronauts Agreement, International Liability for Damage caused by Space Objects , the Convention on Registration and the Moon Agreement.


Be that as it may, it is beyond question that the international scenario is now very different to that of 1986 - a time when the world was still divided in two confronted political units - and it is even more different to the years that followed the adoption of the 1967 Space Treaty when the use of remote sensing technologies was in its early experimental stages. The LANDSAT program, for example, was put into operation by the USA in July 1971.

Another factor of change is the increasing commercialization of space activities in the world of today. The activities of private entities in space are constantly growing. For this reason, no doubt, Professor Bin Cheng includes remote sensing in Part VI of his book STUDIES IN INTERNATIONAL SPACE LAW which deals specifically with commercial space activities (7) . Likewise, the III United Nations Conference on the Exploration and Peaceful Use of Outer Space, held in Vienna in July 1999, put a strong accent on the space industry which, for the first time, had a significant space at this Conference.

It is interesting to have in mind that, at the time of the operation of the LANDSAT program of the seventies, space activities were exclusive to the USA and the USSR. Today, per contra, many States have become active participants in the use of outer space. Brazil, for example, has had its national satellites in the geostationary orbit for over fifteen years. So is the case of Argentina, who also has its scientific satellites operating in the lower orbits.

The unprecedented growth of the commercial aspects of space activities is reflected in the exploitation of the geostationary orbit for telecommunication purposes, the use of remote sensing technologies and launching services.


An attempt will now be made to identify realistic possibilities of advancing on the 1986 Principles over which the Legal Subcommittee of COPUOS took fifteen years to agree upon and which were subsequently adopted by consensus at the United Nations (8).

The regional field is, by and large, the most appropriate scenario for the mentioned objective, particularly at the present stage of evolution of space technologies using remote sensing satellites. That is to say that, on the basis of the 1986 Principles, it seems sensible to start considering the possibility of some kind of regional agreement - of undoubted commercial characteristics - in the Mercosur context. It is today fair to say that the end result of the 1986 text has not really justified the lengthy and patient preparatory work at COPUOS. Anyway, most of the Principles are now part of general international law and, consequently, of a mandatory nature.

Education appears to be an appropriate field for a first stage. To this we may add the multiplicity of commercial possibilities stemming from digital mapping using remote sensing satellites - and its use, as evidence, before national and international courts. We may also list the space technologies applied for advanced weather forecasts and to "produce rain" over regions affected by draught, the detection of subterranean water and related examples.

Brazil and Argentina have established precedents concerning the regulations of remote sensing activities. The joint proposal made by these two countries to the Legal Subcommittee of COPUOS (9) aiming at the adoption of a convention to govern the matter was discussed in detail in this forum in the early seventies. Article V of this proposal established that "States parties shall refrain from undertaking activities of remote sensing of national resources belonging to another State party, including the resources located in maritime areas under national jurisdiction, without the consent of the latter". This meant the inclusion of resources in the continental shelf and exclusive economic zone. Article IX of the joint proposal provided that when a State collected data on the natural resources of another by remote sensing techniques it could by no means transmit or transfer this information without the consent of the sensed State.

Interesting, for its implications, is the fact that the highly industrialized States - particularly the USA during the development of its LANDSAT program – favored policies based on the free distribution of the information collected regardless of the consent of the sensed State. France, for its part, from the very beginning drew a clean line between "primary data" and "analyzed data". In the first case the approach was far more liberal and prior consent was only required for photographs of a very high resolution.

The UN Principles do not address the possibility of distributing information to third States. Principle XII was thoroughly discussed within the framework of Project 2001, a four-year research program on "The Legal Framework for the Commercial Use of Outer Space" (10),conducted by Professor Böckstiegel from Cologne University, with considerable international implications. The conclusion of the Working Group was that Principle XII - which envisages no preferential treatment for the sensed State - did not prohibit the commercialization of data collected by remote sensing technologies. The only protection for the latter is embodied in Principle IV declaring that remote sensing activities should be conducted on the basis of respect for the principle of full and permanent sovereignty of all States and peoples over their own wealth and natural resources, and shall not be conducted in a manner detrimental to the legitimate rights and interests of the sensed State. However, this provision is subject to interpretation with the ensuing dangers and uncertainties this course of action implies.

Bin Cheng (11) underlines the flexibility of Principle I which defines remote sensing activities as the operation of remote sensing space systems, primary data collection and storage stations, and activities in processing, interpreting and disseminating the processed data. However so, the Principles make no reference to the uses that may be given to the collected data which is, indeed, a very serious gap in the law.

In the present state of evolution of international law the most realistic means of protection for sensed States is possibly article VI of the 1967 Space Treaty which makes States responsible for their national activities in space. In some way Principle XIV would be confirming this Article, albeit with a more limited scope, when referring exclusively to remote sensing activities. Thus, any other space activity would remain subject to the "rules of international law on state responsibility".

Principle II contains a clause frequently used in recent international instruments concerning the duty to take into particular consideration the needs of the developing countries. This requirement is repeated in Principles IX, XII and XIII. This clause, to be read jointly with the principle of international cooperation, could be of use to give maximum benefit to developing countries.

On general lines, as indicated previously, the 1986 Principles declare what is today customary international law. Moreover, many of the Principles make express reference to the 1967 Space Treaty of which many provisions reflect international customs of a long-standing tradition.

On the occasion of the Workshop organized within the technical forum of Unispace III to which reference was made earlier, and where Dr. José Monserrat Filho and the present writer took active part, remote sensing issues were the object of careful attention. Among the conclusions drawn from Session 4 of the above-mentioned Workshop dedicated to remote sensing, the already familiar confrontation between freedom of access to data and distribution thereof on the one side, and the growing restrictions imposed on commercial data on the other, were once again made clearly evident (12).

A certain degree of concern was shown at this Workshop in connection with the EUMETSAT procedures. Since 1994 this organization had begun to encrypt the data collected by its remote sensing satellites. In brief, an idea started to gain ground among the participants in the Unispace Workshop -particularly among delegates of developing countries - in the sense that the 1986 UN Principles had become part of State practice today. This, together with a growing opinio juris generalis on the matter, was reason enough to convert the Principles into a binding instrument (13).

To sum up, a number of pillars may be identified upon which the UN Principles are founded, inter alia:

Today, fifteen years after the adoption of the UN Principles, the need to have more precise rules on the matter is beyond question. This objective would probably provide a useful basis for joint cooperation between Argentina and Brazil. It is necessary to fill the gaps in the law governing remote sensing activities and adapt some of these Principles for their application in a globalized world. It is equally important to continue the cooperation efforts between the two countries in the fields of Space Law, strengthened on the occasion of the X Brazilian Symposium on Remote Sensing held in Foz do Iguaçu in April 2001 (14) . The conclusions reached at this meeting are thus indicating and showing us the way.

The time has come to consider the possibility of a "Space Mercosur". As a starting point we may refer to the Argentine-Brazilian cooperation, the participation, debates, conclusions and recommendations stemming from Unispace III, and the findings of the UBACYT Project on "International law and the commercial aspects of space activities" (15), presently conducted by the University of Buenos Aires. In this context, remote sensing technologies and their legal implications take pride of place.


1. Chair of Public International Law, University of Buenos Aires. Senior Career Scientist, National Council of Scientific Research, Argentina. Permanent Rapporteur of the Space Law Committee of the International Law Association (London).     Back

2. This anecdote appears in Harold Macmillan´s Memoirs and is quoted by the present author in "Las Actividades de los Estados en el Espacio Ultraterrestre a la Luz del Derecho Internacional Positivo", Revista del Colegio de Abogados de la Ciudad de Buenos Aires, Tomo XXXIX - N°1, 1979. See also, by the present author, "Earth-surveying from space in the Light of the Principle of Sovereignty" in Proceedings of the XV Colloquium on the Law of Outer Space, Vienna 1972 (IAF- International Institute of Space Law).    Back

3. The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and other Celestial Bodies was open for signature on 27 January 1967. In accordance with its Article 14.3 it entered into force on 10 October of that same year when the fifth instrument of ratification was deposited.     Back

4. See Bin Cheng, op.cit. , loc.cit. in note 7 infra, at p. 572.    Back

5. See Ruiz Moreno, Isidoro, ESTUDIOS DE DERECHO INTERNACIONAL PUBLICO (Movimiento Humanista de Derecho, N°11, Facultad de Derecho, UBA), Buenos Aires 1965, p.36.    Back

6. See Ruiz Moreno, Isidoro, op.cit. in note 4, cit. by Williams, Silvia Maureen in TELECOMUNICACIONES POR SATELITES, published by Abeledo Perrot, Buenos Aires, 1981. This book is based on a doctoral thesis of the author, which was awarded the "Premio Facultad".    Back

7. See Bin Cheng, STUDIES IN INTERNATIONAL SPACE LAW, published by Clarendon Oxford in 1997, Part VI, Chapter 22 entitled "Legal and Commercial Aspects of Data Gathering by Remote Sensing", pp. 572-620.    Back

8.  The Principles are known as "Principles relating to Remote Sensing from Space". They were adopted by UNGA Resolution 41/65 in December 1986.    Back

9. Doc. A/C.1/1047, Treaty on Remote Sensing - Draft Basic Articles.    Back

10. One of the Workshops set up in the Framework of Project 2001 concerned the "Legal Framework for Remote Sensing Activities". See, in particular, the subchapter on "commercialisation of space data" at p.22 of the "Proceedings of Project 2001 - Workshop on Remote Sensing Issues" which reflects the discussions of the Group during a Colloquium held in Toulouse on 28 October 1998.     Back

11. See Cheng, Bin, op.cit. in note 4, p.589 et seq.12.     Back

12. See "Proceedings of the Workshop on Space Law in the Twenty-first Century", organised by the IISL and the United Nations Office for Outer Space Affairs at Vienna, Technical Forum, July 1999, especially Working Session N°4 . Published by the United Nations, New York 2000.    Back

13. Ibid. See, in particular, the positions of Dres. Rebellón Betancourt , Yakovenko and Chandresakhar, commentators of Session N°4 of the Unispace III Workshop.    Back

14. This Symposium was held in Foz do Iguaçu between 21-26 April 2001, under the auspices of the Instituto Nacional de Pesquisas Espaciais (INPE, Ministério da Ciência e Tecnologia), the Sociedade Brasileira de Direito Aerospacial and the Sociedade Latino-Americana de Sensoriamento Remoto e Sistemas de Informaçoes Espaciais of Brazil.    Back

15. At this moment the UBACyT DE0015 Project, sponsored by the University of Buenos Aires and directed by the present writer, is dealing with some of the international legal aspects of Earth observation, in cooperation with participants of Project 2001 (Köln University), the British Institute of International & Comparative Law, the International Law Association and the Institut International de Droit de lÉspace. At the governmental level these teams are liaised with the UN Office for Outer Space Affairs in Vienna.    Back

(Volta ao Sumário)

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