Space colonization (also called space settlement or extraterrestrial colonization) is the use of outer space or celestial bodies other than Earth for permanent habitation or as extraterrestrial territory. The inhabitation and territorial use of extraterrestrial space has been proposed to be realized by for example building space settlements or extraterrestrial mining enterprises. To date, no permanent space settlement other than temporary space habitats have been set up, nor any extraterrestrial territory or land has been legally claimed. Making territorial claims in space is prohibited by international space law, defining space as a common heritage. International space law has had the goal to prevent colonial claims and militarization of space, advocating the installation of international regimes to regulate access to and sharing of space, particularly for specific locations such as the limited space of geostationary orbit or the Moon. Many arguments both for and against space settlement have been made. The two most common in favor of colonization are survival of human civilization and life from Earth in the event of a planetary-scale disaster (natural or human-made), and the availability of additional resources in space that could enable expansion of human society. The most common objections to colonization include concerns that the commodification of the cosmos may be likely to enhance the interests of the already powerful, including major economic and military institutions; enormous opportunity cost as compared to expending the same resources here on Earth; exacerbation of pre-existing detrimental processes such as wars, economic inequality, and environmental degradation. A space settlement would set a precedent that would raise numerous socio-political questions. The mere construction of the needed infrastructure presents a daunting set of technological and economic challenges. Space settlements are generally conceived as organizational and material structures that have to provide for nearly all (or all) the needs of larger numbers of humans, in an environment out in space that is very hostile to human life and inaccessible for maintenance and supply from Earth. It would involve technologies, such as controlled ecological life-support systems, that have yet to be developed in any meaningful way. It would also have to deal with the as-yet-unknown issue of how humans would behave and thrive in such places long-term. Because of the present cost of sending anything from the surface of the Earth into orbit (around $1400 per kg, or $640 per pound, to low Earth orbit by Falcon Heavy), a space settlement would