| Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies | |
|---|---|
 Parties Signatories Non-parties | |
| Signed | 27 January 1967 |
| Location | London,Moscow andWashington, D.C. |
| Effective | 10 October 1967; 58 years ago (1967-10-10) |
| Condition | 5 ratifications, including the depositary Governments |
| Parties | 118[1][2][3][4] |
| Depositary | Governments of the United Kingdom of Great Britain and Northern Ireland, the Union of Soviet Socialist Republics and the United States of America |
| Languages | English, French, Russian, Spanish, Chinese and Arabic |
| Full text | |
 Outer Space Treaty of 1967 atWikisource | |
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TheOuter Space Treaty, formally called theTreaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, is amultilateraltreaty that forms the basis of internationalspace law.
Negotiated and drafted under the auspices of theUnited Nations, it was opened for signature in theUnited States, theUnited Kingdom, and theSoviet Union on 27 January 1967, entering into force on 10 October 1967. As of October 2025[update], 118 countries are parties to the treaty—including all majorspacefaring nations—and another 20 are signatories.[1][5][6]
Key provisions of the treaty include prohibiting nuclear weapons in space; limiting the use of theMoon and all othercelestial bodies to peaceful purposes; establishing that space shall be freely explored and used by all nations; and precluding any country from claiming sovereignty over outer space or any celestial body. Although it forbids establishing military bases, testing weapons and conducting military maneuvers on celestial bodies, the treaty does not expressly ban all military activities in space, nor the establishment ofmilitary space forces or the placement of conventional weapons in space.[7][8]
The OST also declares that space is an area for free use and exploration by all and "shall be the province of all mankind". Drawing heavily from theAntarctic Treaty of 1961, the Outer Space Treaty likewise focuses on regulating certain activities and preventing unrestricted competition that were thought might lead to conflict at that time.[9] Consequently, it is largely silent or ambiguous on newly developed space activities such aslunar andasteroid mining.[10][11][12]
OST was at the heart of a 'network' of inter-state treaties and strategic power negotiations to achieve the best available conditions fornuclear weapons world security.
OST was the most important link in the chain of international legal arrangements for space from the late 1950s to the mid-1980s. The OST was followed by four additional agreements, with varied levels of accession:the safe return of astronauts who land in a foreign country (1967);liability for damages caused by spacecraft (1972); theregistration of space vehicles (1976); andrules for activities on the Moon (1979).[13] As the first and most foundational legal instrument of space law,[14] the Outer Space Treaty and its broader principles of promoting the civil and peaceful use of space continue to underpin multilateral initiatives in space, such as theInternational Space Station and theArtemis Program.[15][16]
The Outer Space Treaty was spurred by the development ofintercontinental ballistic missiles (ICBMs) in the 1950s, which could reach targets throughouter space.[9] The Soviet Union's launch ofSputnik, the first artificial satellite, in October 1957, followed by a subsequentarms race with the United States, hastened proposals to prohibit the use of outer space for military purposes. On 17 October 1963, theU.N. General Assembly unanimously adopted a resolution prohibiting the introduction ofweapons of mass destruction in outer space. Various proposals for an arms control treaty governing outer space were debated during a General Assembly session in December 1966, culminating in the drafting and adoption of the Outer Space Treaty the following January.[9]
The Outer Space Treaty represents the basic legal framework of internationalspace law. According to theU.N. Office for Outer Space Affairs (UNOOSA), the core principles of the treaty are:[17]
Among its principles, it bars states party to the treaty from placingweapons of mass destruction inEarth orbit, installing them on theMoon or any othercelestial body, or otherwise stationing them inouter space. It specifically limits the use of the Moon and other celestial bodies to peaceful purposes, and expressly prohibits their use for testing weapons of any kind, conducting military maneuvers, or establishing military bases, installations, and fortifications (Article IV). However, the treaty does not prohibit the placement ofconventional weapons in orbit, and thus some highly destructive attack tactics, such askinetic bombardment, are still potentially allowable.[18] In addition, the treaty explicitly allows the use of military personnel and resources to support peaceful uses of space, mirroring a common practice permitted by the Antarctic Treaty regarding that continent. The treaty also states that the exploration of outer space shall be done to benefit all countries and that space shall be free for exploration and use by all the states.
Article II of the treaty explicitly forbids any government from "appropriating" a celestial body such as the Moon or a planet, whether by declaration, use, occupation, or "any other means".[19] However, the state that launches a space object, such as a satellite or space station, retains jurisdiction and control over that object;[20] by extension, a state is also liable for damages caused by its space object.[21]
Article VI of the Outer Space Treaty deals with international responsibility, stating that "the activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty" and that States Party shall bear international responsibility for national space activities whether carried out by governmental or non-governmental entities.
As a result of discussions arising fromProject West Ford in 1963, a consultation clause was included in Article IX of the Outer Space Treaty: "A State Party to the Treaty which has reason to believe that an activity or experiment planned by another State Party in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, may request consultation concerning the activity or experiment."[22][23]
Being primarily an arms control treaty for the peaceful use of outer space, the Outer Space Treaty offers limited and ambiguous regulations to newer space activities such aslunar andasteroid mining.[10][12][24] It is therefore debated whether the extraction of resources falls within the prohibitive language of appropriation, or whether the use of such resources encompasses the commercial use and exploitation.[25]
Seeking clearer guidelines, private U.S. companies lobbied the U.S. government, which in 2015 introduced the U.S.Commercial Space Launch Competitiveness Act of 2015 legalizing space mining.[26] Similar national legislation to legalize the appropriation of extraterrestrial resources are now being introduced by other countries, including Luxembourg, Japan, China, India, and Russia.[10][24][27][28] In addition, the U.S. has led the creation of a series of bilateral agreements known as theArtemis Accords that seek to clarify a number of issues related to the Outer Space Treaty, including the use of space resources.[29] This has created some controversy regarding legal claims over the mining of celestial bodies for profit.[24][25]
The "Declaration of the First Meeting of Equatorial Countries", also known as the "Bogota Declaration", was one of the few attempts to challenge the Outer Space Treaty. It was promulgated in 1976 by eightequatorial countries to assertsovereignty over those portions of thegeostationary orbit that continuously lie over the signatory nations' territory.[30] These claims did not receive wider international support or recognition, and were subsequently abandoned.[31]
As the first international legal instrument concerning space, the Outer Space Treaty is considered the "cornerstone" of space law.[32][33] It was also the first major achievement of the United Nations in this area of law, following the adoption of the first U.N. General Assembly resolution on space in 1958,[34] and the first meeting of the U.N.Committee on the Peaceful Uses of Outer Space (COPUOS) the subsequent year.[35]
Within roughly a decade of the treaty's entry into force, several other treaties were brokered by the U.N. to further develop the legal framework for activities in space:[33]
With the exception of the Moon Treaty, to which only 18 nations are party, all other treaties on space law have been ratified by most majorspace-faring nations (namely those capable oforbital spaceflight).[36] COPUOS coordinates these treaties and other questions ofspace jurisdiction, aided by theU.N. Office for Outer Space Affairs.
The Outer Space Treaty was opened for signature in the United States, the United Kingdom, and the Soviet Union on 27 January 1967, and entered into force on 10 October 1967. As of October 2025, 118 countries are parties to the treaty, while another 20 have signed the treaty but have not completed ratification.[1]
Multiple dates indicate the different days in which states submitted their signature or deposition, which varied by location: (L) forLondon, (M) forMoscow, and (W) forWashington, D.C. Also indicated is whether the state became a party by way of signature and subsequentratification, byaccession to the treaty after it had closed for signature, or bysuccession of states after separation from some other party to the treaty.
| State[1][2][3][4] | Signed | Deposited | Method |
|---|---|---|---|
 Afghanistan |
|
| Ratification |
 Algeria | 27 Jan 1992 (W) | Accession | |
 Antigua and Barbuda |
| Succession from United Kingdom | |
 Argentina |
| 26 Mar 1969 (M, W) | Ratification |
 Armenia | 28 Mar 2018 (M) | Accession | |
 Australia | 27 Jan 1967 (W) | 10 Oct 1967 (L, M, W) | Ratification |
 Austria | 20 Feb 1967 (L, M, W) | 26 Feb 1968 (L, M, W) | Ratification |
 Azerbaijan | 9 Sep 2015 (L) | Accession | |
 Bahamas |
| Succession fromUnited Kingdom | |
 Bahrain | 7 Aug 2019 (M) | Accession | |
 Bangladesh |
| Accession | |
 Barbados | 12 Sep 1968 (W) | Accession | |
 Belarus | 10 Feb 1967 (M) | 31 Oct 1967 (M) | Ratification |
 Belgium |
|
| Ratification |
 Benin |
| Accession | |
 Bosnia and Herzegovina | 29 Sep 2020 (L) | Accession | |
 Brazil |
| 5 Mar 1969 (L, M, W) | Ratification |
 Bulgaria | 27 Jan 1967 (L, M, W) |
| Ratification |
 Burkina Faso | 3 Mar 1967 (W) | 18 Jun 1968 (W) | Ratification |
 Canada | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification |
 Chile |
| 8 Oct 1981 (W) | Ratification |
 China |
| Accession | |
 Colombia | 27 Jan 1967 (W) |
| Ratification |
 Croatia | 10 Mar 2023 (W) | Accession | |
 Cuba | 3 Jun 1977 (M) | Accession | |
 Cyprus |
|
| Ratification |
 Czech Republic |
| Succession fromCzechoslovakia | |
 Denmark | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification |
 Dominican Republic | 27 Jan 1967 (W) | 21 Nov 1968 (W) | Ratification |
 Ecuador |
| 7 Mar 1969 (W) | Ratification |
 Egypt | 27 Jan 1967 (M, W) |
| Ratification |
 El Salvador | 27 Jan 1967 (W) | 15 Jan 1969 (W) | Ratification |
 Equatorial Guinea | 16 Jan 1989 (M) | Accession | |
 Estonia | 19 Apr 2010 (M) | Accession | |
 Fiji |
| Succession fromUnited Kingdom | |
 Finland | 27 Jan 1967 (L, M, W) | 12 Jul 1967 (L, M, W) | Ratification |
 France | 25 Sep 1967 (L, M, W) | 5 Aug 1970 (L, M, W) | Ratification |
 Germany | 27 Jan 1967 (L, M, W) | 10 Feb 1971 (L, W) | Ratification |
 Greece | 27 Jan 1967 (W) | 19 Jan 1971 (L) | Ratification |
 Guinea-Bissau | 20 Aug 1976 (M) | Accession | |
 Hungary | 27 Jan 1967 (L, M, W) | 26 Jun 1967 (L, M, W) | Ratification |
 Iceland | 27 Jan 1967 (L, M, W) | 5 Feb 1968 (L, M, W) | Ratification |
 India | 3 Mar 1967 (L, M, W) | 18 Jan 1982 (L, M, W) | Ratification |
 Indonesia |
| 25 Jun 2002 (L) | Ratification |
 Iraq |
|
| Ratification |
 Ireland | 27 Jan 1967 (L, W) |
| Ratification |
 Israel | 27 Jan 1967 (L, M, W) |
| Ratification |
 Italy | 27 Jan 1967 (L, M, W) | 4 May 1972 (L, M, W) | Ratification |
 Jamaica | 29 Jun 1967 (L, M, W) |
| Ratification |
 Japan | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification |
 Kazakhstan | 11 Jun 1998 (M) | Accession | |
 Kenya | 19 Jan 1984 (L) | Accession | |
 North Korea | 5 Mar 2009 (M) | Accession | |
 South Korea | 27 Jan 1967 (W) | 13 Oct 1967 (W) | Ratification |
 Kuwait |
| Accession | |
 Laos |
|
| Ratification |
 Latvia | 23 May 2025 (W) | Accession | |
 Lebanon | 23 Feb 1967 (L, M, W) |
| Ratification |
 Libya | 3 Jul 1968 (W) | Accession | |
 Lithuania | 25 Mar 2013 (W) | Accession | |
 Luxembourg |
| 17 Jan 2006 (L, M, W) | Ratification |
 Madagascar | 22 Aug 1968 (W) | Accession | |
 Malaysia |
| 21 Oct 2025 (W) | Ratification |
 Mali | 11 Jun 1968 (M) | Accession | |
 Malta | 22 May 2017 (L) | Accession | |
 Mauritius |
| Succession fromUnited Kingdom | |
 Mexico | 27 Jan 1967 (L, M, W) | 31 Jan 1968 (L, M, W) | Ratification |
 Mongolia | 27 Jan 1967 (M) | 10 Oct 1967 (M) | Ratification |
 Morocco |
| Accession | |
 Myanmar | 22 May 1967 (L, M, W) | 18 Mar 1970 (L, M, W) | Ratification |
 Nepal |
|
| Ratification |
 Netherlands | 10 Feb 1967 (L, M, W) | 10 Oct 1969 (L, M, W) | Ratification |
 New Zealand | 27 Jan 1967 (L, M, W) | 31 May 1968 (L, M, W) | Ratification |
 Nicaragua |
|
| Ratification |
 Niger | 1 Feb 1967 (W) |
| Ratification |
 Nigeria | 14 Nov 1967 (L) | Accession | |
 Norway | 3 Feb 1967 (L, M, W) | 1 Jul 1969 (L, M, W) | Ratification |
 Oman | 4 Feb 2022 (L) | Accession | |
 Pakistan | 12 Sep 1967 (L, M, W) | 8 Apr 1968 (L, M, W) | Ratification |
 Panama | 27 Jan 1967 (W) | 9 Aug 2023 (W) | Ratification |
 Papua New Guinea |
| Succession fromAustralia | |
 Paraguay | 22 Dec 2016 (L) | Accession | |
 Peru | 30 Jun 1967 (W) |
| Ratification |
 Poland | 27 Jan 1967 (L, M, W) | 30 Jan 1968 (L, M, W) | Ratification |
 Portugal | 29 May 1996 (L) | Accession | |
 Qatar | 13 Mar 2012 (W) | Accession | |
 Romania | 27 Jan 1967 (L, M, W) | 9 Apr 1968 (L, M, W) | Ratification |
 Russia | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification as the Soviet Union |
 Saint Vincent and the Grenadines | 13 May 1999 (L) | Succession fromUnited Kingdom | |
 San Marino |
|
| Ratification |
 Saudi Arabia | 17 Dec 1976 (W) | Accession | |
 Seychelles | 5 Jan 1978 (L) | Accession | |
 Sierra Leone |
|
| Ratification |
 Singapore | 10 Sep 1976 (L, M, W) | Accession | |
 Slovakia |
| Succession fromCzechoslovakia | |
 Slovenia | 8 Feb 2019 (L) | Accession | |
 South Africa | 1 Mar 1967 (W) |
| Ratification |
 Spain |
| Accession | |
 Sri Lanka | 10 Mar 1967 (L) | 18 Nov 1986 (L, M, W) | Ratification |
 Sweden | 27 Jan 1967 (L, M, W) | 11 Oct 1967 (L, M, W) | Ratification |
 Switzerland |
| 18 Dec 1969 (L, M, W) | Ratification |
 Syria | 19 Nov 1968 (M) | Accession | |
 Thailand | 27 Jan 1967 (L, M, W) |
| Ratification |
 Togo | 27 Jan 1967 (W) | 26 Jun 1989 (W) | Ratification |
 Tonga |
| Succession fromUnited Kingdom | |
 Tunisia |
|
| Ratification |
 Turkey | 27 Jan 1967 (L, M, W) | 27 Mar 1968 (L, M, W) | Ratification |
 Uganda | 24 Apr 1968 (W) | Accession | |
 Ukraine | 10 Feb 1967 (M) | 31 Oct 1967 (M) | Ratification |
 United Arab Emirates | 4 Oct 2000 (W) | Accession | |
| United Kingdom | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification |
 United States | 27 Jan 1967 (L, M, W) | 10 Oct 1967 (L, M, W) | Ratification |
 Uruguay |
| 31 Aug 1970 (W) | Ratification |
 Uzbekistan | 17 Oct 2024 (M) | Accession | |
 Venezuela | 27 Jan 1967 (W) | 3 Mar 1970 (W) | Ratification |
 Vietnam | 20 Jun 1980 (M) | Accession | |
 Yemen | 1 Jun 1979 (M) | Accession | |
 Zambia |
| Accession |
TheRepublic of China (Taiwan), which is currently recognized by11 UN member states, ratified the treaty prior to theUnited Nations General Assembly'svote to transfer China's seat to thePeople's Republic of China (PRC) in 1971. When the PRC subsequently ratified the treaty, they described the Republic of China's (ROC) ratification as "illegal". The ROC has committed itself to continue to adhere to the requirements of the treaty, and the United States has declared that it still considers the ROC to be "bound by its obligations".[5]
| State | Signed | Deposited | Method |
|---|---|---|---|
 Republic of China | 27 Jan 1967 | 24 Jul 1970 | Ratification |
20 states have signed but not ratified the treaty.
| State | Signed |
|---|---|
 Bolivia | 27 Jan 1967 (W) |
 Botswana | 27 Jan 1967 (W) |
 Burundi | 27 Jan 1967 (W) |
 Cameroon | 27 Jan 1967 (W) |
 Central African Republic | 27 Jan 1967 (W) |
 Democratic Republic of the Congo |
|
 Ethiopia |
|
 Gambia | 2 Jun 1967 (L) |
 Ghana |
|
 Guyana | 3 Feb 1967 (W) |
 Haiti | 27 Jan 1967 (W) |
 Holy See | 5 Apr 1967 (L) |
 Honduras | 27 Jan 1967 (W) |
 Iran | 27 Jan 1967 (L) |
 Jordan | 2 Feb 1967 (W) |
 Lesotho | 27 Jan 1967 (W) |
 Philippines |
|
 Rwanda | 27 Jan 1967 (W) |
 Somalia | 2 Feb 1967 (W) |
 Trinidad and Tobago |
|
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The remainingUN member states andUnited Nations General Assembly observer states which have neither ratified nor signed the Outer Space Treaty are:[37]
Albania
Andorra
Angola
Belize
Bhutan
Brunei
Cambodia
Cape Verde
Chad
Comoros
Republic of the Congo
Costa Rica
Djibouti
Dominica
East Timor
Eritrea
Eswatini
Gabon
Georgia
Grenada
Guatemala
Guinea
Ivory Coast
Kiribati
Kyrgyzstan
Liberia
Liechtenstein
Malawi
Maldives
Marshall Islands
Mauritania
Federated States of Micronesia
Moldova
Monaco
Montenegro
Mozambique
Namibia
Nauru
North Macedonia
Palau
Palestine
Saint Kitts and Nevis
Saint Lucia
Samoa
São Tomé and Príncipe
Senegal
Serbia
Solomon Islands
South Sudan
Sudan
Suriname
Tajikistan
Tanzania
Turkmenistan
Tuvalu
Vanuatu
Zimbabwe
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