Space Law Explained — Outer Space Treaty & Satellite Rules

*This Insight is intended to have a logical basis but not to be taken as purely factual or legal advice.

Key Points

1. Outer Space Treaty does not provide clear guidance on the legality of satellite-based lasers.
2. One should apply to the ITU when planning a telecommunications satellite.
3. Do not interfere with the remote sensing activities of other states.
4. Do not kill in outer space.
5. One should not appropriate the Moon or any other part of outer space as one’s territory.

Would “Star Wars” have been legal?

The essential feature of the American Strategic Defense Initiative (SDI), often dubbed “Star Wars”, concerned satellite-based lasers. Triggered by relevant information, these would destroy the large majority of any fleet of attacking nuclear missiles during their trajectory through outer space. In that way, United States air defenses would have to cope only with a few remaining incoming missiles.

The Outer Space Treaty provides no clear guidance on the lawfulness of such laser-weapon satellites. The stationing of weapons of mass destruction in space is prohibited, but “weapons of mass destruction” is usually understood to mean nuclear, biological, and chemical weapons. Whether laser-beam weapons would fall within that category is debatable.

Moreover, while SDI’s realization might have increased tensions between the superpowers, its purpose was proclaimed to be defensive. A state has the right to defend itself against armed attacks, and that right does not simply expire because such a defense might involve the use of space. The Treaty, however, adopts a more stringent regime for the Moon and other celestial bodies: they are to be used for “exclusively peaceful purposes.” States have historically disagreed on the scope of “peaceful”—the Soviet Union interpreted it as “non-military,” while the United States viewed it as “non-aggressive,” permitting non-offensive military uses. SDI never reached operational testing, so the question remains largely theoretical.

Answer: One should not station weapons of mass destruction in outer space, but defensive lasers may be lawful.

What are the traffic rules in space?

The answer is not simply “driving left” or “driving right.” “Traffic rules” mainly apply to the first phase of launch and re-entry when a space object traverses national airspace. Before entering outer space, a launch vehicle must pass through airspace; if that is only the launching state’s airspace, national authorities manage safety by clearing aircraft or timing the launch.

The legal difficulty arises when a launch or re-entry path crosses another state’s sovereign airspace. Do spacecraft have an inherent right to cross foreign airspace under a right of access to outer space, or must they obtain authorization from the overflown state? Some argue for a “right of innocent passage” by analogy with maritime law. In practice, passage has usually been permitted so long as the activity is peaceful and coordinated with national authorities about timing and trajectory.

Is there a television without frontiers?

There is no uniform legal answer. Some states argued at the United Nations that broadcasting programs via satellite into other states should be automatically allowed, based on the freedom to undertake space activities (confirmed by the Outer Space Treaty) and the freedom to impart information. Many industrialized liberal states supported this view.

However, most developing states opposed it, arguing that sovereignty over national territories includes the right to prohibit undesired broadcasts to protect cultural and social values. A 1982 UN resolution ultimately accepted the view that broadcasting into another state’s territory depends on that state’s consent. Because the resolution is not legally binding and because many industrialized nations voted against it, there is no global, binding rule: in some states you need consent; in others broadcasters have effectively ignored that restraint.

Answer: Be careful when broadcasting into another state without that state’s consent.

How about phoning home from space?

In practice there are significant restrictions on communications-satellite use despite the general freedom to use outer space. Historically, communications satellites operated from geostationary orbit (about 36,000 km above the equator), which offers two advantages: satellites appear stationary from the ground, and three well-placed satellites can cover over 99% of the world’s population (excluding polar regions).

The International Telecommunication Union (ITU) coordinates the allocation of orbital slots and frequencies for uplink and downlink signals. The ITU acts as a mediator between states and has no enforcement powers, but the coordination system worked satisfactorily until commercial pressures and orbital congestion increased.

Recent technological developments are leading to many telecommunications satellites operating in much lower orbits—sometimes just a few hundred kilometers up—which reduces latency and enables direct hand-held satellite phones. Low-orbit constellations, however, raise legal and coordination challenges because they require many fast-moving satellites. The ground rule remains: coordinate proposed satellite systems through the ITU to minimize interference and protect your operations.

Answer: Apply to the ITU when planning a telecommunications satellite.

Is spying from space allowed?

Yes. Space law does not prohibit spy satellites. By contrast with the case of the U-2 plane shot down over the Soviet Union in 1960 (which violated Soviet sovereign airspace), outer space lies outside individual state borders and can be used freely under the Outer Space Treaty. This freedom includes the use of satellites for reconnaissance.

Shooting down a spy satellite would not necessarily be lawful under that regime. Many satellites serve dual civilian and commercial purposes—detecting minerals, monitoring deforestation and agriculture, tracing environmental pollution—commonly called “remote sensing” or “earth observation.” The prevailing principle is the freedom to gather and distribute information.

A 1986 UN resolution stated that the state being imaged had no exclusive right to the imagery and could not prohibit its collection. While sensed states have rights to consultation and access to data (and sometimes preferential pricing), the baseline remains freedom of observation. Practically: do not interfere with other states’ remote sensing activities.

Answer: You should not interfere with the remote sensing activities of other states.

Can space killers be sentenced to death?

In principle, yes—but it depends on legal jurisdiction and registration. Article VIII of the Outer Space Treaty allows states to register space objects. Registration can allow a state to apply its national laws to objects it registers—similar to how flag state jurisdiction applies to ships and aircraft.

If a state registers a space station and explicitly extends national criminal law to that station, prisoners onboard could be tried under that state’s laws. For example, a murder aboard a U.S.-registered module could be prosecuted under U.S. law; the same act on another partner’s module could be prosecuted under that partner’s law. This raises coordination challenges for international projects such as an international space station composed of modules registered by different partner states and by organizations such as the European Space Agency (which, as an international organization, lacks its own criminal code).

Answer: You should not kill in outer space, either.

Who owns the Moon?

No one can own the Moon. Claims such as those by private individuals (for example, selling lunar real estate) or historical grants (a 17th-century Prussian certificate) cannot be honored: you cannot transfer what you do not possess. Article II of the 1967 Outer Space Treaty expressly excludes national appropriation of outer space, including the Moon, by any means.

Because no global legal regime exists to extend national property law into outer space, courts cannot validly enforce private claims to lunar ownership until relevant states agree on an international system. Similarly, when Neil Armstrong planted the United States flag on the Moon in 1969, he did not annex the Moon or any part of it as U.S. territory. (The planted display was a metal assembly designed to appear as a flag and did not “blow” in windless lunar conditions.)

Answer: One should not appropriate the Moon or any other part of outer space as one’s territory.

FAQ

What is space law?

Space law is an area of international law that governs activities in outer space. It comprises treaties, international agreements, and customary international law that apply to activities in outer space and on celestial bodies such as the Moon and other planets.

Who regulates space law?

Space law is developed and coordinated through the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS). UNCOPUOS provides international leadership and guidance on the legal, scientific, and technical aspects of the exploration and use of outer space.

What are the principles of space law?

Principles include the freedom of exploration and use of outer space by all states, the peaceful use of outer space, and the prevention of harmful interference with the activities of other states. Other principles include freedom of scientific research in outer space, liability of states for damage caused by their space objects, and protection of the outer space environment.

What are the treaties related to space law?

The five major treaties are the Outer Space Treaty, the Rescue Agreement, the Liability Convention, the Registration Convention, and the Moon Agreement. These treaties provide the primary legal framework for the exploration and use of outer space.