Colonization of the Moon is a process or concept employed by some proposals for robotic or human exploitation and settlement endeavours on the Moon. Settling of the Moon is therefore a more specific concept, for which the broader concept of colonization is often used as a synonym, a use that is contested in the light of colonialism.
Laying claim to the Moon has been declared illegal through international space law and no state has made such claims, despite having a range of probes and artificial remains on the Moon.
While a range of proposals for missions of lunar colonization, exploitation or permanent exploration have been raised, current projects for establishing permanent crewed presence on the Moon are not for colonizing the Moon, but rather focus on building moonbases for exploration and to a lesser extent for exploitation of lunar resources.
The commercialization of the Moon is a contentious issue for national and international lunar regulation and laws (such as the Moon treaty).
Colonization of the Moon has been imagined as early as the first half of the 17th century by John Wilkins in A Discourse Concerning a New Planet.
Colonization of the Moon as a material process has been taking place since the first artificial objects reached the Moon after 1959. Luna landers scattered pennants of the Soviet Union on the Moon, and U.S. flags were symbolically planted at their landing sites by the Apollo astronauts, but no nation claims ownership of any part of the Moon's surface. Russia, China, India, and the U.S. are party to the 1967 Outer Space Treaty, which defines the Moon and all outer space as the "province of all mankind", restricting the use of the Moon to peaceful purposes and explicitly banning military installations and weapons of mass destruction from the Moon.
The landing of U.S. astronauts was seen as a precedence for the superiority of the free-market socioeconomic model of the U.S., and in this case as the successful model for space flight, exploration and ultimately human presence in the form of colonization. In the 1970s the word and goal of colonization was discouraged by NASA and funds as well as focus shifted away from the Moon and particularly to Mars. But the U.S. eventually nevertheless opposed the 1979 Moon Agreement which aimed to restrict the exploitation of the Moon and its resources. Subsequently, the treaty has been signed and ratified by only 18 nations, as of January 2020, none of which engage in self-launched human space exploration.
After U.S. missions in the 1990s suggested the presence of lunar water ice, its actual discovery in the soil at the lunar poles by Chandrayaan-1 (ISRO) in 2008–09 renewed interest in the Moon. A range of moonbases have been proposed by states and public actors. Currently the U.S.-led international Artemis program seeks to establish with private contractors a state run orbital lunar way-station in the 2020s, and China proposed with Russia the so-called International Lunar Research Station to be established in the 2030s and aim for an Earth-Moon Space Economic Zone to develop by 2050.
Current proposals mainly have the goal of exploration, but such proposals and projects have increasingly aimed for enabling exploitation or commercialization of the Moon. This move to exploitation has been criticized as colonialist and contrasted by proposals for conservation (e.g. by the organization For All Moonkind), collaborative stewardship (e.g. by the organization Open Lunar Foundation, chaired by Chris Hadfield) and the Declaration of the Rights of the Moon, drawing on the concept of the Rights of Nature for a legal personality of non-human entities in space.
Far from being a colony, the temporary Tranquility Base of the first crewed mission to the Moon in 1969, as well as its successor camps of the Apollo missions, has been the closest to a colony on the Moon so far.
Before and since then a permanent human presence through colonization of the Moon has been pursued and advocated for by a range of civil actors and space advocacy groups. But most importantly different countries have been putting forward concepts and plans for not only new crewed expeditions, but also for moonbases.
The pursued purpose of such moonbases is broad, but is mostly for space exploration, but also for exploiting and commercializing the Moon and advocating for a lunar and cis-lunar infrastructure, economy and settled society.
The most advanced contemporary missions share this spectrum of purpose, between exploration and exploitation. For example, the leading Artemis program and International Lunar Research Station projects, while focusing on exploration, they do both mention prospecting for lunar resource extraction for in-situ resource utilization as an objective, in the case of the American policy including that the Artemis program should furthermore enable resource commercialization and private enterprise.
These bases are planned to be crewed, but only eventually permanently. Commercial proposals though have suggested building and use of moonbases for tourism and possibly settlement.
Although Luna landers scattered pennants of the Soviet Union on the Moon, and U.S. flags were symbolically planted at their landing sites by the Apollo astronauts, no nation claims ownership of any part of the Moon's surface. Likewise no private ownership of parts of the Moon, or as a whole, is considered credible.
The 1967 Outer Space Treaty defines the Moon and all outer space as the "province of all mankind". It restricts the use of the Moon to peaceful purposes, explicitly banning military installations and weapons of mass destruction. A majority of countries are parties of this treaty. The 1979 Moon Agreement was created to elaborate, and restrict the exploitation of the Moon's resources by any single nation, leaving it to a yet unspecified international regulatory regime. As of January 2020, it has been signed and ratified by 18 nations, none of which have human spaceflight capabilities.
Since 2020, countries have joined the U.S. in their Artemis Accords, which are challenging the treaty. The U.S. has furthermore emphasized in a presidential executive order ("Encouraging International Support for the Recovery and Use of Space Resources.") that "the United States does not view outer space as a 'global commons'" and calls the Moon Agreement "a failed attempt at constraining free enterprise."
With Australia signing and ratifying both the Moon Treaty in 1986 as well as the Artemis Accords in 2020, there has been a discussion if they can be harmonized. In this light an Implementation Agreement for the Moon Treaty has been advocated for, as a way to compensate for the shortcomings of the Moon Treaty and to harmonize it with other laws and agreements such as the Artemis Accords, allowing it to be more widely accepted.
In the face of such increasing commercial and national interest, particularly prospecting territories, U.S. lawmakers have introduced in late 2020 specific regulation for the conservation of historic landing sites and interest groups have argued for making such sites World Heritage Sites and zones of scientific value protected zones, all of which add to the legal availability and territorialization of the Moon.In 2021, the Declaration of the Rights of the Moon was created by a group of "lawyers, space archaeologists and concerned citizens", drawing on precedents in the Rights of Nature movement and the concept of legal personality for non-human entities in space.
Space colonization has been discussed as postcolonial continuation of imperialism and colonialism, calling for decolonization instead of colonization. Critics argue that the present politico-legal regimes and their philosophic grounding advantage imperialist development of space and that key decisionmakers in space colonization are often wealthy elites affiliated with private corporations, and that space colonization would primarily appeal to their peers rather than ordinary citizens. Furthermore, it is argued that there is a need for inclusive and democratic participation and implementation of any space exploration, infrastructure or habitation. According to space law expert Michael Dodge, existing space law, such as the Outer Space Treaty, guarantees access to space, but does not enforce social inclusiveness or regulate non-state actors.
Particularly the narrative of the "New Frontier", has been criticized as unreflected continuation of settler colonialism and manifest destiny, continuing the narrative of exploration as fundamental to the assumed human nature. Joon Yun considers space colonization as a solution to human survival and global problems like pollution to be imperialist, as such others have identified space as a new sacrifice zone of colonialism.
More specifically the advocacy for territorial colonization of Mars opposed to habitation in the atmospheric space of Venus has been called surfacism, a concept similar to Thomas Golds surface chauvinism.
More generally space infrastructure such as the Mauna Kea Observatories have also been criticized and protested against as being colonialist. Guiana Space Centre has also been the site of anti-colonial protests, connecting colonization as an issue on Earth and in space.
For long-term sustainability, a space colony should be close to self-sufficient. Mining and refining the Moon's materials on-site – for use both on the Moon and elsewhere in the Solar System – could provide an advantage over deliveries from Earth, as they can be launched into space at a much lower energy cost than from Earth. It is possible that large amounts of cargo would need to be launched into space for interplanetary exploration in the 21st century, and the lower cost of providing goods from the Moon might be attractive.
In the long term, the Moon will likely play an important role in supplying space-based construction facilities with raw materials. Microgravity in space allows for the processing of materials in ways impossible or difficult on Earth, such as "foaming" metals, where a gas is injected into a molten metal, and then the metal is annealed slowly. On Earth, gas bubbles may rise or fall due to their relative density to air, but in a zero gravity environment this does not happen. The annealing process requires large amounts of energy, as a material is kept very hot for an extended period of time (allowing the molecular structure to realign), and this too may be more efficient in space, as the vacuum drastically reduces all heat transfer except through radiative heat loss.
Exporting material to Earth in trade from the Moon is problematic due to the cost of transportation, which would vary greatly if the Moon is industrially developed (see "Launch costs" above). One suggested trade commodity is helium-3 (3He) which is carried by the solar wind and accumulated on the Moon's surface over billions of years, but occurs only rarely on Earth. Helium-3 might be present in the lunar regolith in quantities of 0.01 ppm to 0.05 ppm (depending on soil). In 2006 it had a market price of about $1,500 per gram ($1.5M per kilogram), more than 120 times the value per unit weight of gold and over eight times the value of rhodium.
In the future 3He harvested from the Moon may have a role as a fuel in thermonuclear fusion reactors. It should require about 100 metric tons (220,000 lb) of helium-3 to produce the electricity that Earth uses in a year and there should be enough on the Moon to provide that much for 10,000 years.
To reduce the cost of transport, the Moon could store propellants produced from lunar water at one or several depots between the Earth and the Moon, to resupply rockets or satellites in Earth orbit.
Main article: Lunar water
Lunar scientists had discussed the possibility of water repositories for decades. They are now increasingly "confident that the decades-long debate is over" a report says. "The Moon, in fact, has water in all sorts of places; not just locked up in minerals, but scattered throughout the broken-up surface, and, potentially, in blocks or sheets of ice at depth." The results from the Chandrayaan mission are also "offering a wide array of watery signals."
It is estimated there is at least 600 million tons of ice at the north pole in sheets of relatively pure ice at least a couple of meters thick.
Gerard K. O'Neill, noting the problem of high launch costs in the early 1970s, came up with the idea of building Solar Power Satellites in orbit with materials from the Moon. Launch costs from the Moon would vary significantly if the Moon is industrially developed (see "Launch costs" above). This proposal was based on the contemporary estimates of future launch costs of the Space Shuttle.
On 30 April 1979, the Final Report "Lunar Resources Utilization for Space Construction" by General Dynamics Convair Division under NASA contract, NAS9-15560 concluded that the use of lunar resources would be cheaper than terrestrial materials for a system comprising as few as thirty Solar Power Satellites of 10 GW capacity each.
In 1980, when NASA's launch cost estimates for the Space Shuttle were grossly optimistic, O'Neill et al. published another route to manufacturing using lunar materials with much lower startup costs. This 1980s SPS concept relied less on human presence in space and more on partially self-replicating systems on the lunar surface under telepresence control of workers stationed on Earth.