Let's say that there's a joint mission to the International Space Station, composed of American and British astronauts.

They get along well for the first few days, but tensions grow, and eventually an American crew member kills a one of the British group.

How would the investigation and trial be conducted? Who would investigate? What court would the defendant be tried in?

Is there some kind of "space rulebook" that spells out what to do with murder, or crime in general?

  • While there is law that might apply, no one can be sure until it happens and it could be context specific. For example, some astronauts are considered active duty military personnel and might be subject to court martial, and if the space ship was military, so might civilians on board.
    – ohwilleke
    Commented Apr 3, 2017 at 5:58
  • Everyone votes on who is the most suspicious and ejects them. Commented Dec 17, 2020 at 15:59
  • An even more difficult question would be a Canadian killing a Japanese astronaut, both riding up in a Russian Soyuz, while in a European Space Agency module that was launched by the U.S. Shuttle.
    – DrSheldon
    Commented Jun 6, 2021 at 13:38

2 Answers 2


Maritime law applies in space which means jurisdiction lies with the country of registration of the vessel. So, if the crime occurs in transit then Russia has jurisdiction since, at present, all transportation is provided by Russian Soyuz capsules.

The ISS itself is governed by a number of international treaties, MOU and bi-lateral agreements. In essence:

The basic rule is that 'each partner shall retain jurisdiction and control over the elements it registers and over personnel in or on the Space Station who are its nationals' (Article 5 of the Intergovernmental Agreement).

  • But who owns the ISS? It's mashup of different parts, each built by different countries.
    – Munesawagi
    Commented Aug 3, 2016 at 22:46
  • 2
    @Angelplayer: Why are you assuming single ownership? In fact, why are you even assuming there's a owner at all? Ownership isn't a necessary legal concept when all parties that could have physical control have an agreement. And for the ISS, until SpaceX the only parties with de facto physical access were nation states
    – MSalters
    Commented Aug 4, 2016 at 8:54
  • 1
    @Angelplayer It doesn't matter who built it and where. Think of it this way. If a murder occurred in a vessel registered in the USA, would it matter that the engine was built in Germany, the hull was built in Russia, etc.?
    – A. Darwin
    Commented Aug 4, 2016 at 15:19
  • 2
    Can you add a link to support the assertion that maritime law applies in space? Also, in the hypothetical, does the US prosecute because it has jurisdiction over the murderer, or does the UK prosecute because it has jurisdiction over the victim?
    – phoog
    Commented Aug 6, 2016 at 9:35

Same as high seas. It's international space. The flag of the vessel, or the country of the victim usually handles prosecution but there are additional hurdles.

  • International space is governed by a different set of treaties than the high seas.
    – Mark
    Commented Dec 18, 2020 at 2:23

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