Editing Space colonization (section)

==Justification and opposition to space colonization==
===Justification===
====Survival of human civilization====
{{Main|Space and survival}}

A primary argument calling for space colonization is the long-term survival of human civilization and terrestrial life.<ref>{{Cite web|last=Piper|first=Kelsey|date=22 October 2018|title=Jeff Bezos and Elon Musk want to colonize space to save humanity|url=https://www.vox.com/future-perfect/2018/10/22/17991736/jeff-bezos-elon-musk-colonizing-mars-moon-space-blue-origin-spacex|access-date=2 April 2021|website=Vox|language=en}}</ref> By developing alternative locations off Earth, the planet's species, including humans, could live on in the event of [[Global catastrophic risk|natural or human-made disasters on Earth]].<ref>{{cite book |last=Kaku |first=Michio |author-link=Michio Kaku |title=The Future of Humanity: Terraforming Mars, Interstellar Travel, Immortality, and Our Destiny Beyond Earth |publisher=Doubleday |year=2018 |isbn=978-0385542760 |pages=3–6 |quote=It is as inescapable as the laws of physics that humanity will one day confront some type of [[extinction]]-level [[Extinction event|event]]. ... [W]e face threats [that include] [[global warming]] ... [[Biological warfare|weaponized microbes]] ... [[Quaternary glaciation|the onset of another ice age]] ... the possibility that [[Yellowstone Caldera|the supervolcano under Yellowstone National Park]] may awaken from its long slumber ... [and] another [[Impact event|meteor or cometary impact]] . ... [from one of the] several thousand [[Near-Earth object|NEOs (near-Earth objects)]] that cross the orbit of the Earth. ... Life is too precious to be placed on a single planet . ... Perhaps our fate is to become a multiplanet species that lives [[Interstellar travel|among the stars]].}}</ref>

On two occasions, theoretical physicist and cosmologist [[Stephen Hawking]] argued for space colonization as a means of saving humanity. In 2001, Hawking predicted that the human race would become extinct within the next thousand years unless colonies could be established in space.<ref>{{cite news |last=Highfield |first=Roger |url=https://www.telegraph.co.uk/news/uknews/1359562/Colonies-in-space-may-be-only-hope-says-Hawking.html |title=Colonies in space may be only hope, says Hawking |work=The Telegraph |date=16 October 2001 |access-date=5 August 2012 |archive-url=https://web.archive.org/web/20090426232042/http://www.telegraph.co.uk/news/uknews/1359562/Colonies-in-space-may-be-only-hope-says-Hawking.html |archive-date=26 April 2009 |url-status=live}}</ref> In 2010, he stated that humanity faces two options: either we colonize space within the next two hundred years, or we will face the long-term prospect of [[Human extinction|extinction]].<ref>{{cite news|agency=Press Association|date=9 August 2010|title=Stephen Hawking: mankind must colonise space or die out |first=Stephen|last=Hawking|language=en-GB|work=The Guardian|url=https://www.theguardian.com/science/2010/aug/09/stephen-hawking-human-race-colonise-space|access-date=20 June 2020|issn=0261-3077}}</ref>

In 2005, then [[NASA]] Administrator [[Michael D. Griffin|Michael Griffin]] identified space colonization as the ultimate goal of current spaceflight programs, saying:
{{blockquote|...&nbsp;the goal isn't just scientific exploration&nbsp;... it's also about extending the range of human habitat out from Earth into the solar system as we go forward in time&nbsp;... In the long run, a single-planet species will not survive&nbsp;... If we humans want to survive for hundreds of thousands of millions of years, we must ultimately populate other planets. Now, today the technology is such that this is barely conceivable. We're in the infancy of it.&nbsp;... I'm talking about that one day, I don't know when that day is, but there will be more human beings who live off the Earth than on it. We may well have people living on the Moon. We may have people living on the moons of Jupiter and other planets. We may have people making habitats on asteroids&nbsp;... I know that humans will colonize the solar system and one day go beyond.<ref>{{cite news| url=https://www.washingtonpost.com/wp-dyn/content/article/2005/09/23/AR2005092301691.html| title=NASA's Griffin: 'Humans Will Colonize the Solar System'| date=25 September 2005| newspaper=Washington Post| page=B07| access-date=14 September 2017| archive-url=https://web.archive.org/web/20110604141654/http://www.washingtonpost.com/wp-dyn/content/article/2005/09/23/AR2005092301691.html| archive-date=4 June 2011| url-status=live}}</ref>|sign=|source=}}

[[Louis J. Halle Jr.]], formerly of the [[United States Department of State]], wrote in ''[[Foreign Affairs]]'' (Summer 1980) that the colonization of space will protect humanity in the event of global [[nuclear warfare]].<ref>{{cite journal |url=http://www.foreignaffairs.org/19800601faessay8146/louis-j-halle/a-hopeful-future-for-mankind.html |title=A Hopeful Future for Mankind |first=Louis J. |last=Halle |journal=Foreign Affairs |date=Summer 1980 |doi=10.2307/20040585 |volume=58 |issue=5 |pages=1129–36 |url-status=dead |archive-url=https://web.archive.org/web/20041013051342/http://www.foreignaffairs.org/19800601faessay8146/louis-j-halle/a-hopeful-future-for-mankind.html |archive-date=13 October 2004 |jstor=20040585|url-access=subscription }}</ref> The physicist [[Paul Davies]] also supports the view that if a planetary catastrophe threatens the survival of the human species on Earth, a self-sufficient colony could "reverse-colonize" Earth and restore [[Civilization|human civilization]]. The author and journalist [[William E. Burrows]] and the biochemist [[Robert Shapiro (chemist)|Robert Shapiro]] proposed a private project, the [[Alliance to Rescue Civilization]], with the goal of establishing an off-Earth "[[backup]]" of human civilization.<ref>{{cite news |url=https://www.nytimes.com/2006/08/01/science/01arc.html |title=Life After Earth: Imagining Survival Beyond This Terra Firma |newspaper=The New York Times |first=Richard |last=Morgan |date=1 August 2006 |access-date=23 May 2010 |archive-url=https://web.archive.org/web/20090417023904/http://www.nytimes.com/2006/08/01/science/01arc.html |archive-date=17 April 2009 |url-status=live}}</ref>

Based on his [[Copernican principle]], [[J. Richard Gott]] has estimated that the human race could survive for another 7.8&nbsp;million years, but it is not likely to ever colonize other planets. However, he expressed a hope to be proven wrong, because "colonizing other worlds is our best chance to hedge our bets and improve the survival prospects of our species".<ref>{{cite news |last=Tierney |first=John |url=https://www.nytimes.com/2007/07/17/science/17tier.html?ex=1342324800&en=ccf375ae9f268470&ei=5090&partner=rssuserland&emc=rss |title=A Survival Imperative for Space Colonization |date=17 July 2007 |work=The New York Times |access-date=23 February 2017 |archive-url=https://web.archive.org/web/20170629081936/http://www.nytimes.com/2007/07/17/science/17tier.html?ex=1342324800&en=ccf375ae9f268470&ei=5090&partner=rssuserland&emc=rss |archive-date=29 June 2017 |url-status=live}}</ref>

In a theoretical study from 2019, a group of researchers have pondered the long-term trajectory of human civilization.<ref name=sb01>{{cite journal |last=Baum |first=Seth D. |author-link=Seth Baum |display-authors=etal |date=2019 |title=Long-Term Trajectories of Human Civilization |url=http://gcrinstitute.org/papers/trajectories.pdf |journal=Foresight |volume=21 |issue=1 |location=Bingley |publisher=Emerald Group Publishing |doi=10.1108/FS-04-2018-0037 |pages=53–83 |s2cid=52042667 |access-date=23 September 2019 |archive-url=https://web.archive.org/web/20200102042937/http://gcrinstitute.org/papers/trajectories.pdf |archive-date=2 January 2020 |url-status=live}}</ref> It is argued that due to Earth's finitude as well as the [[Formation and evolution of the Solar System#The Sun and planetary environments|limited duration of the Solar System]], mankind's survival into the far future will very likely require extensive space colonization.<ref name=sb01/>{{rp|8, 22f}} This 'astronomical trajectory' of mankind, as it is termed, could come about in four steps: First step, space colonies could be established at various habitable locations — be it in outer space or on [[Astronomical object|celestial bodies]] away from Earth – and allowed to remain temporarily dependent on support from Earth. In the second step, these colonies could gradually become self-sufficient, enabling them to survive if or when the mother civilization on Earth fails or dies. Third step, the colonies could develop and expand their habitation by themselves on their [[space station]]s or celestial bodies, for example via [[terraforming]]. In the fourth step, the colonies could self-replicate and establish new colonies further into space, a process that could then repeat itself and continue at an [[Exponential growth|exponential rate]] throughout the cosmos. However, this astronomical trajectory may not be a lasting one, as it will most likely be interrupted and eventually decline due to resource depletion or straining competition between various human factions, bringing about some 'star wars' scenario.<ref name=sb01/>{{rp|23–25}}

====Vast resources in space====
{{See also | Steady-state economy #Pushing some of the terrestrial limits into outer space }}
Resources in space, both in materials and energy, are enormous. The [[Solar System]] has enough material and energy to support anywhere from several thousand to over a billion times that of the current Earth-based human population, mostly from the Sun itself.<ref name=ONeill-1977/>{{rp|9|q=Estimated 3000 times the land area of Earth}}<ref>Estimated 10 quadrillion (10<sup>16</sup>) people. Lewis, John S. (1997). ''[[Mining the Sky|Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets]].'' Helix Books/Addison-Wesley. {{ISBN|0-201-32819-4}} version 3.</ref><ref>Estimated 5 quintillion (5 x 10<sup>18</sup>) people. Savage, Marshall (1992, 1994). ''[[The Millennial Project: Colonizing the Galaxy in Eight Easy Steps]].'' Little, Brown. {{ISBN|0-316-77163-5}}.</ref>

Asteroid mining will likely be a key player in space colonization. Water and materials to make structures and shielding can be easily found in asteroids. Instead of resupplying on Earth, mining and fuel stations need to be established on asteroids to facilitate better space travel.<ref>{{cite web |url=https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_I_Phase_II/Sustainable_Human_Exploration |title=Optical Mining of Asteroids, Moons, and Planets to Enable Sustainable Human Exploration and Space Industrialization |archive-url=https://web.archive.org/web/20200304024010/https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_I_Phase_II/Sustainable_Human_Exploration/|archive-date=4 March 2020 |date=6 April 2017 |website=NASA |first=Joel |last=Sercel}}</ref> Optical mining is the term NASA uses to describe extracting materials from asteroids. NASA believes by using propellant derived from asteroids for exploration to the moon, Mars, and beyond will save $100&nbsp;billion. If funding and technology come sooner than estimated, asteroid mining might be possible within a decade.<ref>{{cite web |url=https://www.forbes.com/sites/brucedorminey/2016/05/24/how-to-optically-mine-water-from-an-asteroid/#37f0e05c389f |title=Turning Near-Earth Asteroids Into Strategically-Placed Fuel Dumps |archive-url=https://web.archive.org/web/20170918065620/https://www.forbes.com/sites/brucedorminey/2016/05/24/how-to-optically-mine-water-from-an-asteroid/#37f0e05c389f|archive-date=18 September 2017 |date=May 24, 2016 |website=Forbes|first=Bruce |last=Dorminey}}</ref>

Although some items of the infrastructure requirements above can already be easily produced on Earth and would therefore not be very valuable as trade items (oxygen, water, base metal ores, silicates, etc.), other high-value items are more abundant, more easily produced, of higher quality, or can only be produced in space. These could provide (over the long-term) a high return on the initial investment in space infrastructure.<ref>{{cite journal|first=Mark J. |last=Sonter |url=http://www.spacefuture.com/archive/the_technical_and_economic_feasibility_of_mining_the_near_earth_asteriods.shtml |title=The Technical and Economic Feasibility of Mining the Near-Earth Asteroids |archive-url=https://web.archive.org/web/20080815034645/http://www.spacefuture.com/archive/the_technical_and_economic_feasibility_of_mining_the_near_earth_asteriods.shtml|archive-date=15 August 2008 |journal=49th IAF Congress |date=28 September – 2 October 1998 |location=Melbourne, Australia}}</ref>

Some of these high-value trade goods include precious metals,<ref name="members.nova.org">[http://members.nova.org/~sol/station/ast-mine.htm Asteroid Mining], {{Webarchive|url=https://web.archive.org/web/20080512000822/http://members.nova.org/~sol/station/ast-mine.htm|date=12 May 2008}}. Sol Station.</ref><ref>{{Cite news|last=Whitehouse|first=David|title=Gold rush in space?|publisher=BBC|date=22 July 1999|url=http://news.bbc.co.uk/1/hi/sci/tech/401227.stm|access-date=2009-05-25|archive-url=https://web.archive.org/web/20080307111033/http://news.bbc.co.uk/1/hi/sci/tech/401227.stm|archive-date=7 March 2008|url-status=live}}</ref> gemstones,<ref>{{cite web|title=Two groups look at the economic viability of mining asteroids |first=Bob |last=Yirka |date=23 October 2023 |url=https://phys.org/news/2023-10-groups-economic-viability-asteroids.html|website=phys.org|access-date=18 April 2025}}</ref> power,<ref>Makoto Nagatomo, Susumu Sasaki and Yoshihiro Naruo. [http://www.spacefuture.com/archive/conceptual_study_of_a_solar_power_satellite_sps_2000.shtml Conceptual Study of A Solar Power Satellite, SPS 2000], {{Webarchive|url=https://web.archive.org/web/20080725171510/http://spacefuture.com/archive/conceptual_study_of_a_solar_power_satellite_sps_2000.shtml|date=25 July 2008}}, Proceedings of the 19th International Symposium on Space Technology and Science, Yokohama, Japan, May 1994, pp.&nbsp;469–476 Paper No. ISTS-94-e-04 – Space Future.</ref> solar cells,<ref name="panix.com">[http://www.panix.com/~kingdon/space/manuf.html Space Manufacturing], {{Webarchive|url=https://web.archive.org/web/20080904234210/http://www.panix.com/~kingdon/space/manuf.html|date=4 September 2008}} – Jim Kingdon's space markets page.</ref> ball bearings,<ref name="panix.com"/> semi-conductors,<ref name="panix.com"/> and pharmaceuticals.<ref name="panix.com"/>

The mining and extraction of metals from a small asteroid the size of [[3554 Amun]] or [[(6178) 1986 DA]], both small near-Earth asteroids, may yield 30 times as much metal as humans have mined throughout history. A metal asteroid this size would be worth approximately US$20&nbsp;trillion at 2001 market prices.<ref>{{Cite web|url=https://spacenews.com/national-space-society-applauds-nasa-asteroid-capture-plan/|title=National Space Society Applauds NASA Asteroid Capture Plan|date=11 April 2013|language=en-US|access-date=20 April 2025|website=Space News}}</ref>

The main impediments to commercial exploitation of these resources are the very high cost of initial investment,<ref>{{Cite journal|last=Lee|first=Ricky J.|title=Costing and financing a commercial asteroid mining venture|journal=54th International Astronautical Congress|location=Bremen, Germany|year=2003|id=IAC-03-IAA.3.1.06|url=http://www.aiaa.org/content.cfm?pageid=406&gTable=Paper&gID=16257|access-date=25 May 2009|url-status=dead|archive-url=https://web.archive.org/web/20090809183150/http://www.aiaa.org/content.cfm?pageid=406&gTable=Paper&gID=16257|archive-date=9 August 2009}}</ref> the very long period required for the expected return on those investments (''The Eros Project'' plans a 50-year development),<ref>[http://www.orbdev.com/erosproj.html The Eros Project], {{Webarchive|url=https://web.archive.org/web/20080705103530/http://www.orbdev.com/erosproj.html|date=5 July 2008}} – Orbital Development.</ref> and the fact that the venture has never been carried out before—the high-risk nature of the investment.

====Expansion with fewer negative consequences====
{{Further|Holocene extinction}}

Expansion of humans and technological progress has usually resulted in some form of environmental devastation, and destruction of [[ecosystem]]s and their accompanying [[wildlife]]. In the past, expansion has often come at the expense of displacing many [[indigenous peoples]], the resulting treatment of these peoples ranging anywhere from encroachment to genocide. Because space has no known life, this need not be a consequence, as some space settlement advocates have pointed out.<ref>{{Cite news| url=http://www.space-settlement-institute.org/meaning.html| title=The Meaning of Space Settlement| publisher=Space Settlement Institute| access-date=5 September 2014| archive-url=https://web.archive.org/web/20141003151529/http://www.space-settlement-institute.org/meaning.html| archive-date=3 October 2014| url-status=live}}</ref><ref>Savage, Marshall (1992, 1994). ''[[The Millennial Project: Colonizing the Galaxy in Eight Easy Steps]]''. Little, Brown. {{ISBN|0-316-77163-5}}</ref> However, on some bodies of the Solar System, there is the potential for extant native lifeforms and so the negative consequences of space colonization cannot be dismissed.<ref>See for example, the work of Dr. Alan Marshall in Alan Marshall (1993) '[https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1468-5930.1993.tb00078.x Ethics and the Extraterrestrial Environment]', ''Journal of Applied Philosophy'', Vol. 10, No 2, pp227-237; Alan Marshall (1994) 'Martians Beware', ''New Zealand Science Monthly'', December 1994 issue; Alan Marshall (1997) 'Extraterrestrial Environmentalism', ''Australian Science'', Vol. 18, No. 2, Winter issue, pp. 25–27. July 1997; and "Cosmic Preservationist", The Word: ''[https://www.newscientist.com/article/mg17723765-100-the-word-cosmic-preservationist/ New Scientist],'' January 4th, 2003 issue.</ref>

Counterarguments state that changing only the location but not the logic of exploitation will not create a more sustainable future.<ref name="Yun">{{cite web |first=Joon |last=Yun |website=Worth.com |title=The Problem With Today's Ideas About Space Exploration. |date=2 January 2020 
|url=https://www.worth.com/is-space-the-next-frontier-for-the-same-old-story-of-imperialism/ |access-date=28 June 2020}}</ref>

====Alleviating overpopulation and resource demand====
An argument for space colonization is to mitigate proposed impacts of [[Human overpopulation|overpopulation of Earth]], such as [[resource depletion]].<ref>{{Cite journal|date=1 January 1976|title=The impact of space colonization on world dynamics|journal=Technological Forecasting and Social Change|language=en|volume=9|issue=4|pages=361–99|doi=10.1016/0040-1625(76)90019-6|issn=0040-1625|last1=Vajk|first1=J.Peter}}</ref> If the resources of space were opened to use and viable life-supporting habitats were built, Earth would no longer define the limitations of growth. Although many of Earth's resources are non-renewable, off-planet colonies could satisfy the majority of the planet's resource requirements. With the availability of extraterrestrial resources, demand on terrestrial ones would decline.<ref name="ONeill-1977"/><ref>{{cite book|first=Jerry|last= Pournelle |title=A Step Farther Out |url=https://books.google.com/books?id=vcQWZFu2t4kC|publisher=Ace|date=1979 |access-date=16 April 2025}}</ref> Proponents of this idea include [[Stephen Hawking]]<ref>{{Cite web|date=17 August 2014|title=Stephen Hawking: mankind must move to outer space within a century - Telegraph|url=http://www.telegraph.co.uk/science/space/7935505/Stephen-Hawking-mankind-must-move-to-outer-space-within-a-century.html|access-date=9 August 2021|first=Richard |last=Alleyne |archive-url=https://web.archive.org/web/20140817025438/http://www.telegraph.co.uk/science/space/7935505/Stephen-Hawking-mankind-must-move-to-outer-space-within-a-century.html|archive-date=17 August 2014}}</ref> and [[Gerard K. O'Neill]].<ref name="ONeill-1977"/>

Others including cosmologist [[Carl Sagan]] and science fiction writers [[Arthur C. Clarke]],<ref name="clarkebipeds">{{cite book|title=Greetings, Carbon-Based Bipeds!|date=1999 |first=Arthur C. |last=Clarke |publisher=Voyager |isbn=0-00-224698-8 |url=https://books.google.com/books?id=GbNi8Si_O4UC|access-date=18 April 2025}}</ref> and [[Isaac Asimov]],<ref>''The Good Earth Is Dying'' (1971), [[Isaac Asimov]], (published in ''[[Der Spiegel]]'').</ref> have argued that shipping any excess population into space is not a viable solution to human overpopulation. According to Clarke, "the population battle must be fought or won here on Earth".<ref name = clarkebipeds/> The problem for these authors is not the lack of resources in space (as shown in books such as ''[[Mining the Sky]]''<ref name="Lewis-1996">{{cite book |title=Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets |date=1996 |first=John S.|last=Lewis |publisher=Helix Book |isbn=0-201-47959-1}}</ref>), but the physical impracticality of shipping vast numbers of people into space to "solve" overpopulation on Earth.

====Other arguments====
Advocates for space colonization cite a presumed innate human drive to explore and discover, and call it a quality at the core of progress and thriving civilizations.<ref>{{cite book |last=Clarke |first=Arthur C. |title= Profiles of the Future: An Inquiry Into the Limits of the Possible |chapter-url= https://archive.org/details/profilesoffuture00clar |chapter-url-access= registration |year= 1962 |chapter= Rocket to the Renaissance}}</ref><ref>{{cite web | url= http://www.spacedaily.com/news/oped-03y.html | title= The Space Settlement Summit | last= McKnight |first=John Carter | publisher= Space Daily | date= 20 March 2003 | access-date= 12 March 2013 | archive-url= https://web.archive.org/web/20130514103953/http://www.spacedaily.com/news/oped-03y.html | archive-date= 14 May 2013 | url-status= live }}</ref>

[[Nick Bostrom]] has argued that from a [[utilitarianism|utilitarian]] perspective, space colonization should be a chief goal as it would enable a very large population to live for a very long time (possibly billions of years), which would produce an enormous amount of utility (or happiness).<ref>{{cite journal |url= http://www.nickbostrom.com/astronomical/waste.html |title= Astronomical Waste: The Opportunity Cost of Delayed Technological Development |journal= Utilitas |volume= 15 |number= 3 |date= November 2003 |pages= 308–14 |doi= 10.1017/S0953820800004076 |last1= Bostrom |first1= Nick |citeseerx= 10.1.1.429.2849 |s2cid= 15860897 |access-date=20 October 2009 |archive-url= https://web.archive.org/web/20140409031022/http://www.nickbostrom.com/astronomical/waste.html |archive-date=9 April 2014|url-status= live }}</ref> He claims that it is more important to reduce existential risks to increase the probability of eventual colonization than to accelerate technological development so that space colonization could happen sooner. In his paper, he assumes that the created lives will have positive ethical value despite the problem of [[suffering]].

In a 2001 interview with Freeman Dyson, J.&nbsp;Richard Gott and Sid Goldstein, they were asked for reasons why some humans should live in space.<ref name="dyson">{{cite web |last=Britt |first=Robert Roy |date=8 October 2001 |title=Stephen Hawking: Humanity Must Colonize Space to Survive |url=http://www.space.com/missionlaunches/colonize_why_011008-1.html |url-status=dead |archive-url=https://web.archive.org/web/20101125083046/http://www.space.com/missionlaunches/colonize_why_011008-1.html |archive-date=25 November 2010 |access-date=28 July 2006|website=space.com}}.</ref> Their answers were:
* Spread life and beauty throughout the universe
* Ensure the survival of our species
* Make money through new forms of [[Commercialization of space|space commercialization]] such as [[space-based solar power|solar-power satellites]], [[asteroid mining]], and [[space manufacturing]]
* Save the [[environment (biophysical)|environment]] of Earth by moving people and industry into space
Biotic ethics is a branch of ethics that values life itself. For biotic ethics, and their extension to space as panbiotic ethics, it is a human purpose to secure and propagate life and to use space to maximize life.

=== Opposition ===
Space colonization has been seen as a relief to the problem of [[human overpopulation]] as early as 1758,<ref name = tsr2009>{{cite news|url=https://www.thespacereview.com/article/1296/1 |title=Planetary demographics and space colonization |first=Nader |last=Elhefnawy |archive-url=https://web.archive.org/web/20160513062857/http://www.thespacereview.com/article/1296/1 |archive-date=13 May 2016 |publisher=The Space Review |date=2 February 2009}}</ref><!--would be best if the original article that Otto Diederich Lutken published were put here--> and listed as one of Stephen Hawking's reasons for pursuing space exploration.<ref>{{cite news|url=https://www.telegraph.co.uk/news/science/space/7935505/Stephen-Hawking-mankind-must-move-to-outer-space-within-a-century.html|title=Stephen Hawking: mankind must move to outer space within a century|date=9 August 2010 |last1=Alleyne |first1=Richard |access-date=5 April 2018|archive-url=https://web.archive.org/web/20180423144633/https://www.telegraph.co.uk/news/science/space/7935505/Stephen-Hawking-mankind-must-move-to-outer-space-within-a-century.html|archive-date=23 April 2018 |url-status=live}}</ref> Critics note, however, that a slowdown in population growth rates since the 1980s has alleviated the risk of overpopulation.<ref name = tsr2009/>

Critics also argue that the costs of commercial activity in space are too high to be profitable against Earth-based industries, and hence that it is unlikely to see significant exploitation of space resources in the foreseeable future.<ref name="Marshall">
{{cite journal |last=Marshall |first=P. |year=1981 |title=Nicole Oresme on the Nature, Reflection, and Speed of Light |journal=[[Isis (journal)|Isis]] |volume=72 |issue=3 |pages=357–374 [367–374] |doi=10.1086/352787 |s2cid=144035661}}</ref>

Other objections include concerns that the forthcoming colonization and [[commodification]] of the cosmos is likely to enhance the interests of the already powerful, including major economic and military institutions e.g. the large financial institutions, the major aerospace companies and the [[military–industrial complex]], to lead to new [[war]]s, and to exacerbate pre-existing exploitation of [[Exploitation of labour|workers]] and [[Exploitation of natural resources|resources]], [[economic inequality]], [[poverty]], [[social division]] and [[Social exclusion|marginalization]], environmental degradation, and other detrimental processes or institutions.<ref name="Dickens-MR-2010-11" /><ref name="Dickens-MR-2008-02">{{cite web |last=Dickens |first=Peter |date=1 February 2008 |url=https://monthlyreview.org/2008/02/01/who-really-won-the-space-race/ |title=Who Really Won the Space Race? |archive-url=https://web.archive.org/web/20161003104456/http://monthlyreview.org/2008/02/01/who-really-won-the-space-race/|archive-date=3 October 2016 |website=Monthly Review|url-status=live}}</ref><ref name="Dickens-MR-2017-03">{{cite web |last=Dickens |first=Pet|date=1 March 2017 |url=https://monthlyreview.org/2017/03/01/astronauts-at-work/ |title=Astronauts at Work: The Social Relations of Space Travel |archive-url=https://web.archive.org/web/20170328200150/https://monthlyreview.org/2017/03/01/astronauts-at-work/|archive-date=28 March 2017 |website=Monthly Review|url-status=live}}</ref>

Additional concerns include creating a culture in which humans are no longer seen as human, but rather as material assets. The issues of [[human dignity]], [[morality]], [[philosophy]], [[culture]], [[bioethics]], and the threat of megalomaniac leaders in these new "societies" would all have to be addressed in order for space colonization to meet the [[psychological]] and [[Group (sociology)|social]] needs of people living in isolated colonies.<ref>{{cite web|url=http://er.jsc.nasa.gov/seh/sociology.html |title=Sociology and Space Development |archive-url=https://web.archive.org/web/20080628172018/http://er.jsc.nasa.gov/seh/sociology.html|archive-date=28 June 2008 |first=B. J. |last=Bluth |website=California State University Northridge}}</ref>

As an alternative or addendum for the future of the human race, many science fiction writers have focused on the realm of the 'inner-space', that is the computer-aided exploration of the [[human mind]] and human [[consciousness]]—possibly en route developmentally to a [[Matrioshka Brain]].<ref>{{Cite web|url=https://curiosity.com/topics/a-matrioshka-brain-is-a-computer-the-size-of-a-solar-system-curiosity/|title=A Matrioshka Brain Is A Computer The Size of a Solar System|website=curiosity.com|access-date=14 August 2018|archive-url=https://web.archive.org/web/20180814040151/https://curiosity.com/topics/a-matrioshka-brain-is-a-computer-the-size-of-a-solar-system-curiosity/|archive-date=14 August 2018|url-status=live}}</ref>

[[Robotic spacecraft]] are proposed as an alternative to gain many of the same scientific advantages without the limited mission duration and high cost of life support and return transportation involved in human missions.<ref>{{Cite news|url=https://www.scientificamerican.com/report/robotic-planetary-exploration/|title=Robotic Exploration of the Solar System|work=Scientific American|access-date=14 August 2018|language=en|archive-url=https://web.archive.org/web/20180814040634/https://www.scientificamerican.com/report/robotic-planetary-exploration/|archive-date=14 August 2018 |url-status=live}}</ref>

A corollary to the [[Fermi paradox]]—"nobody else is doing it"<ref>{{Cite news|url=https://www.forbes.com/sites/startswithabang/2018/06/26/no-we-cannot-know-whether-humans-are-alone-in-the-universe/|title=No, We Haven't Solved The Drake Equation, The Fermi Paradox, Or Whether Humans Are Alone|last=Siegel|first=Ethan|work=Forbes|access-date=14 August 2018|language=en|archive-url=https://web.archive.org/web/20180814041251/https://www.forbes.com/sites/startswithabang/2018/06/26/no-we-cannot-know-whether-humans-are-alone-in-the-universe/|archive-date=14 August 2018|url-status=live}}</ref>—is the argument that, because no evidence of [[Fermi paradox#Alien constructs|alien colonization technology]] exists, it is statistically unlikely to even be possible to use that same level of technology ourselves.<ref>{{Cite news|url=https://www.businessinsider.com/why-aliens-have-not-contacted-humans-2015-9|title=The likeliest reasons why we haven't contacted aliens are deeply unsettling |first=Kelly |last=Dickerson|work=Business Insider|access-date=14 August 2018|archive-url=https://web.archive.org/web/20180814040227/https://www.businessinsider.com/why-aliens-have-not-contacted-humans-2015-9|archive-date=14 August 2018|url-status=live}}</ref>

====Colonialism====
{{See also|Manifest destiny|Space advocacy#Decolonizing space|Space ethics|Ethics of terraforming|Planetary chauvinism}}
[[File:Gemini5insignia.png|thumb|upright=0.6|[[Gemini 5]] mission badge (1965) connecting spaceflight to colonial endeavours<ref name="Roger Launiuss Blog 2011">{{cite web | author=[[Roger Launius|Launius, Roger]]| title=Reconsidering the Foundations of Human Spaceflight in the 1950s | website=Roger Launius's Blog | date=8 June 2011 | url=https://launiusr.wordpress.com/2011/06/08/reconsidering-the-foundations-of-human-spaceflight-in-the-1950s/ | access-date=6 September 2021}}</ref>]]

[[Image:NASA Artemis Gateway logo.png|thumb|upright=0.6|The logo and name of the [[Lunar Gateway]] references the [[St. Louis]] [[Gateway Arch]],<ref>{{cite web|url=https://www.space.com/nasa-lunar-gateway-moon-station-logo.html|title=NASA Reveals New Gateway Logo for Artemis Lunar Orbit Way Station|website=Space.com|date=18 September 2019|access-date=28 June 2020|first=Robert Z. |last=Pearlman}}</ref> which some see as associating Mars with the [[American frontier]] and the ''[[manifest destiny]]'' mentality of [[Settler colonialism#Settler colonialism in the United States|American settler colonialism]].<ref name="NPR.org 2015">{{cite web | title=As Gateway Arch Turns 50, Its Message Gets Reframed |first=Camille |last=Phillips | website=NPR.org | date=28 October 2015 | url=https://www.npr.org/2015/10/28/452299164/as-gateway-arch-turns-50-its-message-gets-reframed | access-date=27 June 2022}}</ref>]]

Space colonization has been discussed as [[postcolonialism|postcolonial]]<ref name="Durrani 2019">{{cite magazine | last=Durrani | first=Haris | title=Is Spaceflight Colonialism? | website=The Nation | date=19 July 2019 | url=https://www.thenation.com/article/world/apollo-space-lunar-rockets-colonialism/ | access-date=2 October 2020}}</ref> continuation of [[imperialism]] and [[colonialism]],<ref>{{cite news |last=Cornish |first=Gabrielle |date=22 July 2019 |title=How imperialism shaped the race to the moon |url=https://www.washingtonpost.com/outlook/2019/07/22/how-imperialism-shaped-race-moon/ |url-status=live |archive-url=https://web.archive.org/web/20190723032005/https://www.washingtonpost.com/outlook/2019/07/22/how-imperialism-shaped-race-moon/ |archive-date=23 July 2019 |access-date=19 September 2019 |newspaper=[[The Washington Post]] |language=en}}</ref><ref name="Haskins"/><ref name="Drake2018"/><ref name="marshall"/> calling for [[decolonization]] instead of colonization.<ref name="Bartels 2018h"/><ref name="Drake2018"/> Critics argue that the present politico-legal regimes and their philosophic grounding, advantage imperialist development of space,<ref name="marshall">{{cite journal |doi=10.1016/0265-9646(95)93233-B |title=Development and imperialism in space |first=Alan |last=Marshall |date=February 1995 |journal=Space Policy |pages=41–52 |access-date=28 June 2020 |url=https://www.sciencedirect.com/science/article/abs/pii/026596469593233B |volume=11|issue=1 |bibcode=1995SpPol..11...41M|url-access=subscription }}</ref> 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.<ref name="DNLee"/><ref>{{cite web|title=Against Mars-a-Lago: Why SpaceX's Mars colonization plan should terrify you|url=https://www.salon.com/2017/10/08/against-mars-a-lago-why-spacexs-mars-colonization-plan-should-terrify-you/|website=Salon.com|access-date=20 September 2019|date=8 October 2017|first=Keith A. |last=Spencer|language=en|archive-url=https://web.archive.org/web/20190919201220/https://www.salon.com/2017/10/08/against-mars-a-lago-why-spacexs-mars-colonization-plan-should-terrify-you/|archive-date=19 September 2019|url-status=live}}</ref> Furthermore, it is argued that there is a need for inclusive<ref>{{cite web |last=Zevallos |first=Zuleyka |date=26 March 2015 |title=Rethinking the Narrative of Mars Colonisation |url=https://othersociologist.com/2015/03/26/rethinking-the-narrative-of-mars-colonisation/ |url-status=live |archive-url=https://web.archive.org/web/20191211122431/https://othersociologist.com/2015/03/26/rethinking-the-narrative-of-mars-colonisation/ |archive-date=11 December 2019 |access-date=20 September 2019 |website=Other Sociologist |language=en}}</ref> and democratic participation and implementation of any space exploration, infrastructure or habitation.<ref name="Tavares Buckner Burton McKaig 2020">{{cite arXiv | last1=Tavares | first1=Frank | last2=Buckner | first2=Denise | last3=Burton | first3=Dana | last4=McKaig | first4=Jordan | last5=Prem | first5=Parvathy | last6=Ravanis | first6=Eleni | last7=Trevino | first7=Natalie | last8=Venkatesan | first8=Aparna | last9=Vance | first9=Steven D. | last10=Vidaurri | first10=Monica | last11=Walkowicz | first11=Lucianne | last12=Wilhelm | first12=Mary Beth | title=Ethical Exploration and the Role of Planetary Protection in Disrupting Colonial Practices | date=15 October 2020 | class=astro-ph.IM | eprint =2010.08344v2}}</ref><ref>{{cite web |last=Spencer |first=Keith A. |date=2 May 2017 |title=Keep the Red Planet Red |url=https://www.jacobinmag.com/2017/02/mars-elon-musk-space-exploration-nasa-colonization |url-status=live |archive-url=https://web.archive.org/web/20191103165331/https://jacobinmag.com/2017/02/mars-elon-musk-space-exploration-nasa-colonization |archive-date=3 November 2019 |access-date=20 September 2019 |website=[[Jacobin (magazine)|Jacobin]] |language=en}}</ref> 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.<ref name="Bartels 2018h">{{cite web | last=Bartels | first=Meghan | title=People are calling for a movement to decolonize space—here's why | website=Newsweek | date=25 May 2018 | url=https://www.newsweek.com/should-we-colonize-space-some-people-argue-we-need-decolonize-it-instead-945130 | access-date=9 November 2021}}</ref>

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]].<ref name="Schaberg 2021">{{cite web | last=Schaberg | first=Christopher | title=We're Already Colonizing Mars | website=Slate Magazine | date=30 March 2021 | url=https://slate.com/technology/2021/03/mars-colonization-is-already-happening.html | access-date=8 September 2021}}</ref><ref name="Renstrom 2021">{{cite web | last=Renstrom | first=Joelle | title=The Troubling Rhetoric of Space Exploration | website=Undark Magazine | date=18 March 2021 | url=https://undark.org/2021/03/18/rhetoric-of-space-exploration/ | access-date=15 August 2021}}</ref><ref name="Haskins">{{cite web|title=The racist language of space exploration|url=https://theoutline.com/post/5809/the-racist-language-of-space-exploration|website=The Outline|access-date=20 September 2019|date=14 August 2018|first=Caroline |last=Haskins|language=en|archive-url=https://web.archive.org/web/20191016235916/https://theoutline.com/post/5809/the-racist-language-of-space-exploration|archive-date=16 October 2019|url-status=live}}</ref><ref name="DNLee">{{cite web |last=Lee |first=D. N. |date=26 March 2015 |title=When discussing Humanity's next move to space, the language we use matters |url=https://blogs.scientificamerican.com/urban-scientist/when-discussing-humanity-8217-s-next-move-to-space-the-language-we-use-matters/ |url-status=live |archive-url=https://web.archive.org/web/20190914011756/https://blogs.scientificamerican.com/urban-scientist/when-discussing-humanity-8217-s-next-move-to-space-the-language-we-use-matters/ |archive-date=14 September 2019 |access-date=20 September 2019 |website=[[Scientific American]] |language=en}}</ref><ref name="Drake2018">{{cite web|date=9 November 2018|title=We need to change the way we talk about space exploration|first=Nadia|last=Drake|author-link=Nadia Drake|publisher=[[National Geographic]]|access-date=19 October 2019 |url=https://www.nationalgeographic.com/science/article/we-need-to-change-way-we-talk-about-space-exploration-mars|archive-url=https://web.archive.org/web/20191016235826/https://www.nationalgeographic.com/science/2018/11/we-need-to-change-way-we-talk-about-space-exploration-mars/|archive-date=16 October 2019|url-status=live}}</ref> Joon Yun considers [[Space and survival|space colonization as a solution to human survival]] and global problems like pollution to be imperialist;<ref>{{cite web |last=Yun |first=Joon |date=2 January 2020 |title=The Problem With Today's Ideas About Space Exploration. |url=https://www.worth.com/is-space-the-next-frontier-for-the-same-old-story-of-imperialism/ |access-date=28 June 2020 |website=Worth.com}}</ref> others have identified space as a new [[sacrifice zone]] of colonialism.<ref name="Calma 2021">{{cite web | last=Calma | first=Justine | title=Jeff Bezos eyes space as a new 'sacrifice zone' | website=The Verge | date=21 July 2021 | url=https://www.theverge.com/2021/7/21/22587249/jeff-bezos-space-pollution-industry-sacrifice-zone-amazon-environmental-justice | access-date=9 November 2021}}</ref>

Furthermore, the understanding of space as empty and separate is considered a continuation of [[terra nullius]].<ref name="w462">{{cite web | title=Astro-Colonialism: Conversation with Willi Lempert | website=Society for Cultural Anthropology | date=26 March 2024 | url=https://culanth.org/fieldsights/astro-colonialism-conversation-with-willi-lempert | access-date=4 January 2025 |first=Hae-Seo |last=Kim}}</ref><ref name="c593">{{cite journal | last1=Mitchell | first1=A. | last2=Wright | first2=S. | last3=Suchet-Pearson | first3=S. | last4=Lloyd | first4=K. | last5=Burarrwanga | first5=L. | last6=Ganambarr | first6=R. | last7=Ganambarr-Stubbs | first7=M. | last8=Ganambarr | first8=B. | last9=Maymuru | first9=D. | last10=Maymuru | first10=R. | title=Dukarr lakarama: Listening to Guwak, talking back to space colonization | journal=Political Geography | publisher=Elsevier BV | volume=81 | year=2020 | issn=0962-6298 | doi=10.1016/j.polgeo.2020.102218 | doi-access=free | page=102218 | url=https://hal.science/hal-04689795/document | access-date=4 January 2025}}</ref>

Natalie B. Trevino argues that not colonialism but [[decoloniality|coloniality]] will be carried into space if not reflected on.<ref name="Trevino 2021">{{cite thesis | last=Trevino | first=Natalie B | title=The Cosmos is Not Finished |type=PhD dissertation |publisher=University of Western Ontario | date=30 October 2020 | url=https://ir.lib.uwo.ca/etd/7567 | access-date=9 September 2021}}</ref>

More specifically the advocacy for territorial colonization [[Mars colonization|of Mars]] has been called ''surfacism'', in contrast to [[Venus colonization|habitation in the atmospheric space of Venus]],<ref name="Tickle 2015">{{cite web | last=Tickle | first=Glen | title=A Look into Whether Humans Should Try to Colonize Venus Instead of Mars | website=Laughing Squid | date=5 March 2015 | url=https://laughingsquid.com/a-look-into-whether-humans-should-try-to-colonize-venus-instead-of-mars/ | access-date=1 September 2021}}</ref><ref>{{cite web |last=Warmflash |first=David |date=14 March 2017 |title=Colonization of the Venusian Clouds: Is 'Surfacism' Clouding Our Judgement? |url=https://www.visionlearning.com/blog/2017/03/14/colonization-venusian-clouds-surfacism-clouding-judgement/ |url-status=dead |archive-url=https://web.archive.org/web/20191211122431/https://www.visionlearning.com/blog/2017/03/14/colonization-venusian-clouds-surfacism-clouding-judgement/ |archive-date=11 December 2019 |access-date=20 September 2019 |website=Vision Learning |language=en}}</ref> a concept similar to [[Thomas Gold]]s ''[[surface chauvinism]]''.

More generally space infrastructure such as the [[Mauna Kea Observatories]] have also been [[Opposition to the Mauna Kea Observatories|criticized and protested against]] as being colonialist.<ref name="Matson Nunn 2021">{{cite web | last1=Matson | first1=Zannah Mae | last2=Nunn | first2=Neil | title=Space Infrastructure, Empire, And The Final Frontier: What The Mauna Kea Land Defenders Teach Us About Colonial Totality | website=Society & Space | date=6 September 2021 | url=https://www.societyandspace.org/articles/space-infrastructure-empire-and-the-final-frontier-what-the-mauna-kea-land-defenders-teach-us-about-colonial-totality | access-date=7 September 2021}}</ref> [[Guiana Space Centre]] has also been the site of anti-colonial protests, connecting colonization as an issue on Earth and in space.<ref name="Durrani 2019"/>

In regard to the scenario of [[first contact (science fiction)|extraterrestrial]] [[first contact (anthropology)|first contact]], it has been argued that the employment of colonial language would endanger such first impressions and encounters.<ref name="Bartels 2018h"/>

Furthermore, spaceflight as a whole and space law more particularly has been criticized as a postcolonial project by being built on a colonial legacy and by not facilitating the sharing of access to space and its benefits, too often allowing spaceflight to be used to sustain colonialism and imperialism, most of all on Earth instead.<ref name="Durrani 2019"/>

====Planetary protection and risk of contamination====

{{see also|Planetary protection}}
Agencies conducting interplanetary missions are guided by [[Committee on Space Research|COSPAR]]'s planetary protection policies, to have at most 300,000 spores on the exterior of the craft—and more thoroughly sterilized if they contact "special regions" containing water, or it could contaminate life-detection experiments or the planet itself.<ref name=groundwatercontamination>[https://www.bbc.co.uk/news/uk-northern-ireland-27526981 Queens University Belfast scientist helps NASA Mars project] {{Webarchive|url=https://web.archive.org/web/20181119091228/https://www.bbc.co.uk/news/uk-northern-ireland-27526981 |date=19 November 2018}} "No-one has yet proved that there is deep groundwater on Mars, but it is plausible as there is certainly surface ice and atmospheric water vapour, so we wouldn't want to contaminate it and make it unusable by the introduction of micro-organisms."</ref><ref>[https://science.nasa.gov/media/medialibrary/2012/05/04/COSPAR_Planetary_Protection_Policy_v3-24-11.pdf Cospar Planetary Protection Policy], {{webarchive|url=https://web.archive.org/web/20130306111646/https://science.nasa.gov/media/medialibrary/2012/05/04/COSPAR_Planetary_Protection_Policy_v3-24-11.pdf|date=6 March 2013}} (20 October 2002; As Amended to 24 March 2011).</ref>

It is impossible to sterilize human missions to this level, as humans are host to typically a hundred trillion [[microorganism]]s of thousands of species of the [[human microbiome]], and these cannot be removed while preserving the life of the human. Containment seems the only option, but it is a major challenge in the event of a hard landing (i.e. crash).<ref name=biospherescollide>{{cite web|url=https://www.nasa.gov/history/history-publications-and-resources/nasa-history-series/when-biospheres-collide/#.U_uVh_mwJcQ |title=When Biospheres Collide – a History of NASA's Planetary Protection Programs |archive-url=https://web.archive.org/web/20190714112103/https://www.nasa.gov/connect/ebooks/when_biospheres_collide_detail.html#.U_uVh_mwJcQ |archive-date=14 July 2019 |first=Michael |last=Meltzer |date=31 May 2012 |quote=see Chapter 7, Return to Mars – final section: Should we do away with human missions to sensitive targets|access-date=18 April 2025}}</ref> There have been several planetary workshops on this issue, but with no final guidelines yet for a way forward.<ref>Johnson, James E. [http://www.hou.usra.edu/meetings/ppw2015/pdf/1010.pdf "Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions: Goals and Scope." (2015)] {{Webarchive|url=https://web.archive.org/web/20191026125720/https://www.hou.usra.edu/meetings/ppw2015/pdf/1010.pdf |date=26 October 2019 }}</ref> Human explorers could also inadvertently contaminate Earth if they return to the planet while carrying extraterrestrial microorganisms.<ref>{{cite book |title=Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface |date=2002 |url=https://nap.nationalacademies.org/catalog/10360/safe-on-mars-precursor-measurements-necessary-to-support-human-operations |chapter=Potential Hazards of the Biological Environment (Chapter 5) |publisher=National Academies Press |location=Washington, DC |doi=10.17226/10360 |isbn=978-0-309-08426-0 |access-date=19 April 2025 |quote=Martian biological contamination may occur if astronauts breathe contaminated dust or if they contact material that is introduced into their habitat. If an astronaut becomes contaminated or infected, it is conceivable that he or she could transmit Martian biological entities or even disease to fellow astronauts, or introduce such entities into the biosphere upon returning to Earth. A contaminated vehicle or item of equipment returned to Earth could also be a source of contamination}}</ref>