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On Terraforming (Part Two: Is it Legal?)

There’s a long and short answer to the question of whether terraforming is legal, and (un)fortunately one word covers both: maybe. In this post I’ll examine terraforming in the context of space law as it exists at present. There’s nothing[1] stopping the states of the world from drafting a terraforming Mars treaty, but until they do, space law as it exists is what we’ve got. There are in essence two major ‘issues’ with terraforming in the context of the Outer Space Treaty and related space law: the non-appropriation principle in Article II of the Outer Space Treaty (OST) and ‘Planetary Protection’.

Article II, VI and IX of the Outer Space Treaty are the most important articles for questions relating to terraforming, however there are other relevant aspects of space law that I will also discuss. Though before I get too deep into these topics it is probably worth giving a brief introductory overview of space law. I expect most of my readers are probably reasonably familiar and if not, you can also have a look back at the archives of this blog to see some more in-depth discussions, particularly around Article II of the Outer Space Treaty, but nevertheless I will provide an overview here.


Or if you prefer a video, AstrobiologyOU has got you covered

Space law as the term itself would suggest is the body of law (predominantly international but there is a growing and important body of national law in many countries around the world) which governs human activities in outer space. The primary instrument is the Outer Space Treaty of 1967 which lays out the fundamental principles of space law – chief among these being the freedom of use and access for all countries and the ‘non-appropriation’ principle designed to prevent Earth states from annexing territory in outer space. There are four other ‘space law treaties’: the Rescue Agreement (about the rescue and return of astronauts and space objects); the Registration Convention (concerning the registration of objects launched into outer space); the Liability Convention (concerning liability for damage caused by space objects); and the Moon Agreement (an attempted development of the OST more focused on surface activities, while not as dead as claimed it does have a low number of state parties and thus has limited direct relevance to many space law questions.) These treaties are the ‘space specific ones’ but all of international law applies to activities in outer space. Further, there are ‘non-binding’ or ‘soft law’ instruments which also shape the space governance regime, most notably, for our purposes, is ‘planetary protection’ but more on that in a moment.

The Outer Space Treaty is the central framework for space governance, and therefore it makes sense to start with that. As mentioned, Article II is one of the more important elements especially for this particular discussion. Article II, which codifies the ‘non-appropriation principle,’ prohibits the appropriation of outer space, the Moon, and other celestial bodies (which includes everything from the smallest asteroid to Jupiter, and the Sun too) by means of use, occupation, claims of sovereignty or any other means. The use of ‘any other means’ makes this a fairly broad prohibition, but it is important to note that it prohibits the use of those means to appropriate outer space not necessarily those means itself (except, of course, where those means – such as a claim of sovereignty – can’t be anything other than appropriation). A state can still use outer space, but that use does not give rise to a right to appropriate (for example, Apollo 11 was perfectly legitimate activity under the OST but the fact that Apollo 11 landed on the Moon or even in the Sea of Tranquillity doesn’t give the USA any special rights over the territory.[2])

So, the question is, does terraforming constitute ‘national appropriation’ as defined by Article II OST? This is where the ‘by other means’ part of the article becomes important as that indicates an intention to interpret this broadly. Terraforming itself could be one of those other means. Terraforming is a fairly significant transformation of a planetary environment, to undertake such a transformation has implications about power and control of the world in question, therefore even if done ‘for the benefit of humanity’ by one nation or actor, the act of terraforming alone could constitute appropriation – to put it simply to claim that you have the right to make such a change is in essence a form of claim to ownership. And that’s without even considering the history of the claim that the act of ‘improvement’ generates property rights.[3] Whether or not terraforming itself constitutes appropriation, a nation authorising either itself or a private entity (be they a real person or an artificial legal entity like a corporation) to conduct terraforming would probably constitute a claim of sovereignty; only a sovereign would have the authority to authorise such an activity. This issue isn’t necessarily solved by going through the UN or any other body as the UN and other international bodies only have authority due to the devolved/transferred authority of their member states[4] and if the member states can’t appropriate celestial bodies then they can’t authorise the UN to do so either (though this is something of a legal technicality as the international community could either amend the Outer Space Treaty or ratify a new treaty which does give the UN authority, but lots of areas of legal practice rest on these sorts of technicalities so it’s also not meaningless, particularly if you take the view that the rule of law matters.)

The non-appropriation principle isn’t the only potential legal obstacle for terraformers. Article III OST stipulates that all of international law applies in outer space, this potentially means that international environmental law applies in outer space, however in the absence of a known biosphere that may not be too much of a barrier beyond the difficulties of adhering to things like the precautionary principle. The ban on nuclear explosions in the Partial and Comprehensive Test Ban Treaties, as well as the Treaty Prohibiting Nuclear Weapons[5], renders one of the proposed methods of ‘warming’ Mars (see previous post) incompatible with international law (stay tuned for more ways terraforming methods may be incompatible with international law). While again this isn’t necessarily insurmountable, the nature and purpose of nuclear explosive devices may give reason to pause on whether this is a barrier that is worth ‘surmounting.’ Nuclear weapons are a scourge of humanity and should be eliminated (as the 5 leading nuclear powers are legally bound to do under the Non-Proliferation Treaty), whether using them to terraform Mars could be a ‘good’ use for them (particularly if part of their elimination) is a reasonable point for discussion, but ‘nuking Mars’ is certainly not something that should be discussed lightly.

That was a thinly veiled reference to Elon Musk, which raises the next legal issue, the application of international space law to individuals and corporate entities. Despite what Musk may have claimed (believes) he cannot escape the Outer Space Treaty. While the Treaty itself applies directly neither to himself nor to SpaceX as an American citizen and a US company they are subject to US law and the US is required to ‘authorise and continually supervise’ the activities of its nationals in outer space (Article VI OST) which is why the US requires licences for launches.[6] These licences need to be compatible with the US government’s obligations under international law. Granted this relies on how the US interprets its international obligations (and the international community’s willingness and ability to hold it to those obligations). The other side of the Article VI coin is that states are responsible for their nationals in outer space, so governments cannot distance themselves from the actions or behaviours of private individuals or entities as they have an international legal obligation specifically to authorise and supervise these activities. This could be particularly relevant for certain forms of terraforming activities such as releasing genetically engineered organisms intended to alter the atmosphere, the temptation to ‘covertly’ release such organisms among certain pro-terraforming space enthusiasts may be quite strong, but states have a duty to ensure this doesn’t happen (and a lack of national law banning such an action isn’t an excuse for failure to adhere to the international obligation).

Speaking of releasing organisms, Article IX of the Outer Space Treaty, and the Planetary Protection regime, will also present issues for terraforming. Article IX OST says that states must avoid the ‘harmful contamination’ of other celestial bodies, as well as avoid ‘harmful interference’ with the activities of other states. Harmful contamination is somewhat of a high bar, it isn’t enough for contamination to occur, but it needs to be harmful, which then prompts the question, to what or whom? So far, the response to this question has been the ‘planetary protection’ measures developed by COSPAR and various space agencies which focus on protecting the ‘scientific integrity’ of celestial bodies (if we find life on Mars, we want to be sure it is Martian life and not Earth life that hitched a ride).


A video produced by AstrobiologyOU providing an overview of planetary protection

Though there may be an argument for a broader ‘environmental’ approach to space governance.


Andrea Owe’s keynote provides an excellent overview of ‘space environmental ethics’

Article 7 of the Moon Agreement does go further than ‘harmful contamination’ stipulating that states should prevent disrupting the existing balance of the environment. However, as mentioned the Moon Agreement does not have many parties and therefore this idea could be regarded as having been rejected by the international community.[7] It is also worth noting that the proposed definition for Ecocide includes ‘outer space.’[8] So, the case for a broader approach is not without merit. I’ll get more into this in the next post because it involves a discussion about ‘ethics’ and the ‘value’ of environments, but the building blocks of a legal approach are there.

Stepping back a tad – the duty to avoid harmful interference with the activities of others in Article IX OST may also have relevance. While ‘harmful interference’ generally refers to radio interference there may be potential for a broader reading. Mars is a primary target for the search for life and terraforming would certainly interfere with that search. This is not the strongest basis to oppose terraforming, and the activities protected from harmful interference may need to be actively ongoing at the time in question but it does highlight the need for any future governance of activity in outer space to think beyond the activity in question, whether on Mars, the Moon, or simply Earth orbit.

Framing this post with the question ‘is terraforming legal?’ was a tad cheeky, there isn’t really a yes or no answer but as I have discussed there are a number of fairly big issues presented by space law as it exists. Now, a ‘simple’ solution, and one favoured by certain segments of the space expansionist cohort would be to either ignore space law or to change it. The first option is a bad idea, while existing space law is far from perfect it does create a reasonably stable rules-based environment that enables space activities to, well, happen (without international rules on radio frequencies communications satellites couldn’t exist as interference would be a nightmare). The second option is a possibility, and the regime has evolved over the years (see the developments on the topic of space resources since 2015). However, for something as big as terraforming this requires a genuine discussion about values, goals, objectives. This can’t be as simple as ‘is it legal’, we must also ask ‘is it right’, ‘sensible’, ‘ethical’ and so on. Terraforming Mars would be an epochal project and would draw on considerable global resources and talent, its not enough for it to be ‘legal,’ as the next post will discuss.

[1]Well, actually there are a few…

[2]Any rights the US may have are firmly attached to the object(s), so you can’t go and take ownership of what remains of the Apollo 11 lander, at least not without the OK of the US government – despite what has been claimed private property hasn’t been banned in outer space,

[3]Which is too much to cover in this post, but suffice it to say that claims of ‘improvement’ were one of the prime ‘justifications’ for stealing lands from Indigenous peoples around the world

[4]Overly simplistic but basically if it’s not yours you can’t give it to someone else

[5]These three treaties have different levels of acceptance and strength in international law but suffice it to say there is a broad acceptance of a ban on nuclear explosions (weapons or not), which is re-enforced by Article IV of the Outer Space Treaty

[6]See Title 51 USC §50940(a) – it’s also why debates about whether Art VI is ‘self-executing’ are a tad moot, as Congress has incorporated Art VI into US Federal Law

[7]Though the focus for objection to the Moon Agreement did, and does, centre on the Common Heritage of Mankind principle in Article 11, but that is too much to get into here

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