Skip to content

Contents of this page

Five space-specific treaties

Outer Space Treaty (1967)

105 ratifications + 25 signatures

The Outer Space Treaty sets the constitutive foundations for all exploration and use of outer space. It is the broadest of all the space-specific treaties and the later space-specific treaties can be seen as supplements to the Outer Space Treaty.

Rescue and Return Agreement (1968)

95 ratifications + 24 signatures

The Rescue and Return Agreement provides for the rescue and return of astronauts in distress and of space objects to their launching authorities.

Liability Convention (1972)

94 ratifications + 20 signatures

The Liability Convention defines the circumstances in which a launching State is liable for a space object, deals with the case of multiple ‘launching States’ in respect of the one space object, describes how a claim might be made, within a one-year timeframe, and provides for the establishment of an ad hoc Claims Commission to settle claims between two or more States.

Registration Convention (1975)

63 ratifications + 4 signatures

The Registration Convention provides for the registration of space objects by the, or one of the, launching States in respect of a space object.

Moon Agreement (1979)

18 ratifications + 4 signatures

Australia is one of only 18 States Party to the Moon Agreement. It covers not just the Moon, but all celestial bodies. It expands on several articles of the Outer Space Treaty, including Article I, which describes the exploration and use of outer space as the ‘province’ of humanity, on a basis of equality, plus the related provision in Article II that no State may claim sovereignty over any part of outer space (including the Moon and other celestial bodies), and Article IV which significantly limits military activities on the Moon and other celestial bodies.

The Moon Agreement provides extra detail about the specific mode of cooperative use, and most significantly, foreshadows an international regime, to be settled among States Parties, for exploitation of the natural resources of the Moon and other celestial bodies.

Click here for the latest information on the status of the five space-specific treaties.


Basic Principles of International Space Law

The topic of the legal delimitation between the upper limit of airspace and the lower limit of outer space has been on the agenda of the Committee on the Peaceful Uses of Outer Space (COPUOS) since its inception in 1957, but many States have resisted attempts to provide a definition.

Nevertheless, it is considered clear that international space law applies to objects in orbit and beyond, that it applies to things that may be described as ‘space objects’ including rockets from at least the moment of ‘intentional ignition’, it applies to astronauts and it applies to any conduct that may be described as a ‘national activity in outer space’.

Article I of the Outer Space Treaty provides that: “Outer 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, and there shall be free access to all areas of celestial bodies.”

No limitations can be presumed – every State can develop and use rocket technology and satellite technology, notwithstanding that the rockets could conceivably be used as missiles and the satellites used for spying. However, such use must be in accordance with international law, including the Charter of the United Nations, which prohibits the threat or use of force against other States (Article 2(4)).

Article I of the Outer Space Treaty provides: “The exploration and use of outer space, including the Moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development …”.

It is not clear the extent to which a space activity by a national of one State must provide some benefit to other States (as opposed to benefit only for the State involved in the activity), but the practice of States tends to suggest that it is a very low threshold, if there is any threshold at all.

Article I of the Outer Space Treaty provides: “The exploration and use of outer space, including the Moon and other celestial bodies, … shall be the province of all mankind”.

This element of the Outer Space Treaty is perhaps the most nebulous, but it suggests that the right of States to govern the space domain is secondary to the right of humanity as a whole to govern the space domain.

However, there is currently no polity that could be said to be representative of humanity as a whole. This creates some uncertainty about further development of governance frameworks for outer space.

Article II of the Outer Space Treaty provides: “Outer 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.”

This has been interpreted as a bar to any assertion of property rights by any State, commercial entity or private person over any part of outer space, although whether it applies to space resources once they have been extracted from a celestial body remains uncertain.

Both the United States and Luxembourg have passed national legislation purporting to grant property rights over any resources extracted from a celestial body. This unilateral action by the United States and Luxembourg remains a matter of considerable controversy and the issue of a legal regime for resource exploitation in outer space will likely remain a matter of debate in the Committee on the Peaceful Uses of Outer Space (COPUOS) for some time.

For Australia, this is complicated by the fact that Australia is one of only 18 States Parties to the Moon Agreement, which reiterates the apparent bar to any assertion of property rights and adds a concept of outer space as the ‘common heritage of mankind’. Article 11(5) of the Moon Agreement foreshadows the establishment of an international regime (instead of disparate, unilateral, national regimes) for resource exploitation and this may put Australia in a strong position to work towards to the establishment of such an international regime.

Article III of the Outer Space Treaty provides: “States Parties to the Treaty shall carry on activities in the exploration and use of outer space, including the Moon and other celestial bodies, in accordance with international law, including the Charter of the United Nations, in the interest of maintaining international peace and security and promoting international cooperation and understanding.”

Thus, outer space is subject to the application of the broad body of international law generally.

This would include, for example, the inherent right of national self-defence, recognised in Article 51 of the Charter of the United Nations and therefore defensive military activities in outer space would be lawful. The conduct of those activities would be subject to relevant elements of the Laws of Armed Conflict.

Other areas of international law that may be relevant could include international human rights law and international environmental law. The detail of the application of these other areas of international law remains unclear though.

Article IV of the Outer Space Treaty provides: “States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.”

There is no restriction, though, on the transit of weapons of mass destruction through outer space, nor any restrictions on conventional weapons, although Article IV goes on to list some specific prohibitions on military activities on the Moon and other celestial bodies.

The preamble to the Outer Space Treaty refers to the use of outer space for ‘peaceful purposes’. However, the preamble is not an operative part of the treaty.

Article III is an operative part of the treaty and recognises the application of the Charter of the United Nations, which respects the sovereignty of States, up to acts of aggression. Thus, it has generally been accepted that military uses of outer space are not prohibited.

The Outer Space Treaty is a little more specific in Article IV though: “The Moon and other celestial bodies shall be used by all States Parties to the Treaty exclusively for peaceful purposes. The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military manoeuvres on celestial bodies shall be forbidden. The use of military personnel for scientific research or for any other peaceful purposes shall not be prohibited. The use of any equipment or facility necessary for peaceful exploration of the Moon and other celestial bodies shall also not be prohibited.”

The exact meaning of “exclusively for peaceful purposes” remains especially unclear. One interpretation involves the complete demilitarisation of the Moon and other celestial bodies. Another interpretation limits the meaning of “exclusively for peaceful purposes” to specific restrictions listed in Article IV.

Article VI of the Outer Space Treaty establishes a regime of government responsibility for anything that may be regarded as a “national activity in outer space”, even by non-governmental entities that have no connection with the government whatsoever.

This responsibility at least encompasses a duty of the government to ‘authorise and continually supervise’ the space activities non-governmental entities.  States may implement this through policy, or through national legislative licensing regimes, as is the case in Australia.

At its highest, Article VI would imply that a State is responsible for the activities of one of its non-governmental entities even where the non-governmental entity sought a licence, was denied a licence, but went ahead with the activity in defiance of its own government (for example, via a foreign launch). In this scenario, although the State may be responsible, in accordance with Article VI, the consequence of that responsibility should not be assumed to be equivalent to the non-governmental entity itself – that is, the non-governmental entity may bear the consequences far more heavily than the State itself. The State may sufficiently discharge its responsibility by ensuring that the non-governmental entity is dealt with appropriately.

Article VIII of the Outer Space Treaty anticipates that States will maintain a national register of space objects and the Registration Convention imposes an obligation on ‘launching States’ to provide information of an international register of space objects maintained by the United Nations Office of Outer Space Affairs (UNOOSA).

In Australia, the Space Agency provides the information to UNOOSA, using information provided to the Space Agency by a licence-holder.

The term ‘launching State’ is defined as the State which launches or procures the launch of a space object, or whose territory or facility is used for the launch of a space object – giving rise to the possibility of more than one ‘launching State’ in respect of a single space object. The Registration Convention anticipates this scenario and provides that ‘launching States’ shall determine between them, which is to be the State of registry.

Article VIII of the Outer Space Treaty recognises that the State of registry retains jurisdiction and control over the space object.

Although other States may have laws and conduct activities that have some impact on the space object, such laws and activities would be invalid or unlawful respectively, to the extent that they amounted to control over the space object. That is, only the State of registry can take enforcement action involving the space object.

However, Article VIII recognises that another State might own parts of the space object or even the whole of the space object, independently of the State of registry.

The two concepts (registration and ownership) are separate. Clearly, a State with proprietary interests, but which is not the State of registry, would want to protect its interests by some other means, such as a contract (through the non-governmental entities involved) and/or a bilateral treaty.

‘Cooperation and mutual assistance’ is a broad, guiding principle under Art IX of the Outer Space Treaty, although it is manifested in more definitive obligations, such as rescue and return, due regard and international consultations prior to any expected harmful interference.

Article IX of the Outer Space Treaty provides that: “States Parties to the Treaty … shall conduct all their activities in outer space, including the Moon and other celestial bodies, with due regard to the corresponding interests of all other States Parties to the Treaty.”

The phrase ‘due regard’ is not further defined in the space-specific treaties.

Nevertheless, there is a growing body of technical and regulatory norms of more and less global character. It appears likely that, were a court called on to apply Article IX to an apparent lack of ‘due regard’, it would draw on a relatively rich body of national and international jurisprudence about the meaning of ‘due diligence’ in a variety of contexts, and would also draw on the growing body of technical and regulatory norms, in order to conclude what, in any specific instance, could be said to amount to a lack of due regard.

However, the law is a long way from such clarity at present.

Article IX of the Outer Space Treaty provides that: “If a State Party to the Treaty has reason to believe that an activity or experiment planned by it or its nationals in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities of other States Parties in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, it shall undertake appropriate international consultations before proceeding with any such activity or experiment.”

State practice suggests a relatively high threshold of harm before a State would be obliged to undertake appropriate international consultations.

When China created a lot of space debris in 2007 by testing an anti-satellite missile on one of its own satellites, very few States suggested that China should have undertaken prior international consultations. Similarly, no States suggested that India should have undertaken prior international consultations in 2019 when it also tested an anti-satellite missile on one of its own satellites, causing space debris.

Article IX of the Outer Space Treaty provides that: “States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.”

The term ‘harmful contamination’ is not further defined.

Nevertheless, the international, non-governmental organisation, the Committee on Space Research (COSPAR) has been developing a ‘Planetary Protection Policy’ for many years and this represents that best available account of what should be regarded as ‘harmful contamination’ to be avoided.

The Rescue and Return Agreement 1968 expands on the obligation of rescue and return of astronauts in Article V of the Outer Space Treaty. The Rescue and Return Agreement encompasses a positive obligation to rescue astronauts, even outside a State’s jurisdiction, if the State is in a position to do so, and return them to the ‘launching authority’.

There is an obligation to recover and return space objects that have come down within a State’s jurisdiction, but in areas beyond the State’s jurisdiction, the obligation only arises if the space object is passively ‘found’ in such areas. The costs of recovery and return can be claimed from the ‘launching authority’. The term ‘launching authority’ in the Rescue and Return Agreement, as opposed to ‘State of registry’, or ‘launching State’ elsewhere, creates some confusion and uncertainty about the scope of the phrase.

The Liability Convention expands on Article VII of the Outer Space Treaty.

The launching State is absolutely liable for damage caused by its space objects on Earth (including to an aircraft in flight). However, in space, the launching State is only liable if the damage is due to its fault or the fault of someone for whom it is responsible. 

The term ‘launching State’ is defined as the State which launches or procures the launch of a space object, or whose territory or facility is used for the launch of a space object.

The Liability Convention covers circumstances where there are two or more launching States. It also covers the manner of making and settling a claim, including through a multi-national Claims Commission. There has been no definitive instance of the application of the Liability Convention, so there is considerable uncertainty about how it would operate in practice.


National Implementation of International Space Law

States seek to discharge their responsibility, and mitigate their exposure to liability through licensing, permits and insurance requirements

The space-specific treaties place a heavy burden of responsibility, and exposure to liability, on States in respect of national space activities, even where a non-governmental entity is otherwise unconnected with the government (and perhaps operates in open defiance of the government).

Generally, States seek to discharge their responsibility, and mitigate their exposure to liability, by actively authorising (or denying) licences and permits for space activities and by requiring that non-governmental entities have insurance for their activities that covers the government.

That is the case, for example, in respect of Australia, the United Kingdom, the United States, France, and more recently, New Zealand. India and China have operated on the basis of policy decisions, reflecting the lack of commercial space activities in those countries. In both cases, that is changing and China has recently adopted legislation and India is on the cusp of doing so.

Technically, a State is only responsible for conduct that amounts to a ‘national activity in outer space’. The scope of this term is unclear.

Space activity legislation in most States extends to activities of nationals abroad, so the term is generally thought to encompass any activity within the territory of a State, as well as any activity by a national of the State. The term is not limited to activity actually physically in space.

For example, a rocket is generally considered to be a space activity at least from the moment of intentional ignition, even if the attempted launch goes awry. More difficult examples include space object laser-tracking, the space effects of which are minimal, and yet it is undoubtedly a space-related activity.

The scope of the term ‘national activity in outer space’ gives rise to the possibility of overlapping licensing regimes, such that an aspiring space entrepreneur from Australia, seeking to have a satellite launched in the United Kingdom, for example, would have to get a licence in two jurisdictions.

Some legislation, such as in Australia and New Zealand, foreshadows reciprocal recognition arrangements, but in practice, such arrangements are rare throughout the world (compare this to the aviation industry in which the Chicago Convention 1944 facilitates global recognition of aircraft airworthiness certificates).