Outer Space Treaty
What It Says, What It Doesn’t, and Why Every Space Company Should Know It
Section titled “What It Says, What It Doesn’t, and Why Every Space Company Should Know It”A plain-language guide to the 57-year-old document that still runs the final frontier.
The Foundation No One Reads
Section titled “The Foundation No One Reads”In January 1967, with the Cold War running hot and the Moon suddenly within reach, the United States, the Soviet Union, and the United Kingdom signed a treaty. Its goal was straightforward, if audacious: stop the space race from becoming a space war, and establish ground rules for a domain no human had yet set foot in.
The Outer Space Treaty — formally, the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies — entered into force in October 1967. It has 17 articles. It runs fewer than 2,000 words. And it remains the closest thing humanity has to a constitution for space.
As of January 1, 2026, 118 countries have ratified it, including every major spacefaring nation. The near-universal adoption, combined with that striking brevity, is exactly why it creates as many questions as it answers — particularly now, as commercial space shifts from government programme to venture-funded industry.
Here is what it actually says, where it goes silent, and why it matters to anyone building a business beyond Earth.
The Six Principles That Actually Matter
Section titled “The Six Principles That Actually Matter”1. Space Belongs to Everyone — and to No One
Section titled “1. Space Belongs to Everyone — and to No One”Article I sets the tone. Outer space, including the Moon and other celestial bodies, is described as “the province of all mankind.” Exploration shall be free, open to all states, and conducted for the benefit of every country — not just the ones with space programmes.
No border checks. No “keep out” signs backed by legal force.
Article II makes this concrete: no country can claim sovereignty over outer space or any celestial body. Planting a flag on the Moon and legally calling it yours is not an option under international law. The United States cannot own Mars. China cannot own the far side of the Moon. This is called the non-appropriation principle, and it is the bedrock of space law.
The principle is unambiguous when applied to states — the entities that signed and ratified the OST. What it means for private companies — as such not directly bound to the OST — is more challenging to assess.
2. Space Is for Peaceful Purposes (Mostly)
Section titled “2. Space Is for Peaceful Purposes (Mostly)”Article IV does two things, and separating them matters because they apply to different parts of space.
For the Moon and other celestial bodies: a full peaceful-use requirement. No military bases, no weapons testing, no manoeuvres. Military personnel may be present, but only for scientific or other peaceful activities.
For Earth orbit and the rest of outer space (excluding celestial bodies): the rule is narrower. States cannot place nuclear weapons or other weapons of mass destruction in orbit or station them anywhere in space. Conventional weapons? The Treaty says nothing. Satellites with dual uses (military-civilian)? Not prohibited.
This distinction carries real commercial weight. GPS is a military system. So is much of the reconnaissance infrastructure in low Earth orbit. The OST bans none of it. What it bans is the extreme category: WMDs orbiting Earth.
3. States Are Responsible — Even for Private Companies
Section titled “3. States Are Responsible — Even for Private Companies”This is where the Treaty gets commercially significant, and where some space companis are genuinely surprised.
Article VI establishes that states bear “international responsibility” for national activities in outer space, whether those activities are conducted by government agencies or private companies. The state must also “authorize and continuously supervise” any non-governmental actors operating under its jurisdiction.
In plain terms: if a private company causes a problem in space, the state that authorised it is on the hook under international law. This is precisely why every country with a growing domestic space sector has — or is urgently putting in place — a national space law or at least a licensing regime. That regime is how a state discharges its supervisory obligation under the OST.
Article VII layers liability on top: the state that launches an object, or from whose territory or facility it was launched, is internationally liable for damage that object causes — whether on Earth or in space to another state’s spacecraft.
The 1972 Liability Convention (a separate treaty that builds directly on the OST) draws a key distinction here. Damage caused on Earth’s surface triggers absolute liability — the launching state pays regardless of fault. Damage caused in space triggers fault-based liability — the claimant state must prove negligence. If two satellites collide in orbit, the burden is on the aggrieved party to demonstrate the other spacecraft behaved carelessly. That is a harder case to make.
4. Jurisdiction Follows the Registry
Section titled “4. Jurisdiction Follows the Registry”Article VIII establishes the flag state principle. The country in whose registry a space object is listed retains jurisdiction and control over it — even when it is orbiting at 500 kilometres altitude or sitting on the lunar surface.
This is why states maintain formal registries, a process expanded upon by the 1976 Registration Convention. It is also why the choice of where to register a spacecraft matters commercially, in the same way choosing where to incorporate a company or flag a ship carries legal and regulatory consequences.
5. Astronauts Are Envoys of Mankind
Section titled “5. Astronauts Are Envoys of Mankind”Article V requires states to regard astronauts as “envoys of mankind” and to render every possible assistance to any astronaut in distress. The 1968 Rescue Agreement elaborates: states must assist and promptly return any astronaut who lands in their territory, regardless of which country launched them. During the Cold War, this was a meaningful political commitment.
Today, with commercial crew missions multiplying and space tourism broadening the pool of people reaching orbit, the question of who qualifies as an “astronaut” under the Outer Space Treaty is less settled than the text suggests. The OST does not define the term.
6. Transparency and Consultation
Section titled “6. Transparency and Consultation”Articles IX and XI impose lighter-touch obligations. States must conduct activities with “due regard” to the interests of others, and must inform the United Nations Secretary-General and the broader international community of their space activities.
Where a state believes another’s planned activity could cause harmful interference with its own operations, it may request consultation. That is a diplomatic friction mechanism — not a veto, and not enforceable. There is no international body with authority to halt an activity. Consultation is the ceiling of what the Treaty provides.
The Three Big Gaps
Section titled “The Three Big Gaps”Gap 1: Asteroid Mining
Section titled “Gap 1: Asteroid Mining”Article II prohibits national appropriation of celestial bodies by states. But does extracting resources from them — and selling those resources — constitute appropriation? The Treaty does not say.
The US Commercial Space Launch Competitiveness Act (2015) answered this question for American companies: no, extraction is not appropriation. Under US law, companies can own the resources they take from space, in the same way a fishing vessel owns the fish it hauls aboard (according to their view). Luxembourg passed equivalent legislation in 2017. The UAE followed. Several other states are considering similar frameworks.
Other countries and a significant body of international legal opinion disagree. The “province of all mankind” language in Article I, they argue, creates a collective interest in space resources that cannot simply be privatised through domestic legislation — whatever one nation’s courts might say.
This is genuinely unsettled international law. No international court has resolved it. No consensus has formed. The tension between commercial resource extraction and the non-appropriation principle is the single most commercially significant legal uncertainty in the industry today.
Gap 2: Enforcement Mechanism
Section titled “Gap 2: Enforcement Mechanism”The OST has no court. No sanctions regime. No international authority empowered to investigate violations or impose consequences. Compliance rests on diplomatic pressure, reciprocity, and political will.
When Russia conducted an anti-satellite missile test in 2021 — creating thousands of pieces of orbital debris and endangering the crew of the International Space Station — the available response under space law was: condemnation in press releases, statements at the United Nations, and informal diplomatic channels.
For commercial operators, this means the legal environment in orbit is less like regulated airspace and more like international waters. Norms exist. Enforcement is another matter.
Gap 3: The Treaty Was Written Before Commercial Space Existed
Section titled “Gap 3: The Treaty Was Written Before Commercial Space Existed”The OST’s drafters had governments in mind. The word “company” does not appear in the text. Satellite mega-constellations, space tourism, in-orbit manufacturing, private lunar landers — none of these concepts were on the table in 1967.
Article VI’s requirement that states “authorize and continuously supervise” private actors was a prescient piece of drafting, but it delegates the hard questions entirely to national law. The result is a patchwork: some states have thorough licensing regimes; others have almost nothing. The Treaty sets no minimum standard for what adequate supervision looks like.
A Brief Note on the Moon Agreement
Section titled “A Brief Note on the Moon Agreement”The 1979 Moon Agreement attempted to close the resource extraction gap by declaring the Moon and its natural resources the “common heritage of mankind” — a legal concept implying that any commercial benefit must be shared internationally before extraction can begin, under a framework yet to be established.
It has never been ratified by the United States, Russia, China, or any other major spacefaring nation.
Why This Matters Right Now
Section titled “Why This Matters Right Now”The first generation of space law was written when only superpowers had rockets. The second generation is being written now — through national licensing laws, bilateral agreements, and frameworks like the Artemis Accords.
The Artemis Accords (2020), led by NASA and now signed by over 40 countries, address transparency, interoperability, space resource extraction rights, and the “safety zones” around operations on celestial bodies. They are not a treaty and do not override the OST, but they represent the clearest signal yet of where the United States and its partners intend space governance to go.
For anyone building in this industry — launching satellites, planning lunar missions, developing in-orbit infrastructure, or investing in any of the above — the OST is the floor everything else is built on. Understanding what it says, what it deliberately leaves open, and where the current debates are, is not a legal technicality. It is operational knowledge.