What is Space colonization?
[[File:Mars Food Production - Bisected.jpg|thumb|273x273px|Depiction of [[NASA]]'s plan to grow food on [[Mars]]]] [[File:O Neill cylinder-Island Three-Example for nearly 77 million population in each cylinder.png|thumb|273x273px|Millions of people could live in [[space habitat|space habitats]] such as O'Neill cylinder space settlements, as the one shown here]] '''Space colonization'''{{Efn|Also called ''interstellar colonisation'', ''space settlement'', ''space humanization'', ''space habitation'' and ''extraterrestrial colonization''.}} is the idea of [[human]]s living outside of [[Earth]] permanently.<ref name=nasa1 >{{cite web|url=http://settlement.arc.nasa.gov/75SummerStudy/Chapt.1.html|title=Chapter 1: The Colonization of Space|publisher=NASA|accessdate=2012-08-10|archive-date=2012-05-09|archive-url=https://web.archive.org/web/20120509153345/http://settlement.arc.nasa.gov/75SummerStudy/Chapt.1.html|url-status=dead}}</ref> At present, there are no space colonies. However, many people have put forward ideas and thought about the first space colony. Some national [[space program]]s see space colonization as a long-term goal.<ref name=wash>{{cite web|url=https://www.washingtonpost.com/wp-dyn/content/article/2005/09/23/AR2005092301691.html|title=NASA's Griffin: 'Humans Will Colonize the Solar System'|publisher=The Washington Post|date=2005-09-25|accessdate=2012-08-10}}</ref> Building colonies in space would require access to [[water]], food, space, people, building materials, energy, transportation, [[communication]]s, [[life support system|life support]], [[simulated gravity]], [[radiation]] protection and [[investment|money]]. Launching things from Earth is expensive, so it is better if the materials come from the place of the colony. Possible sites for space colonies include the [[Moon]], [[Colonization of Mars|Mars]], [[asteroid]]s and big, free-floating [[space station]]s. Resources, such as [[solar power|solar energy]] and water, are available from or on the Moon, Mars, [[near-Earth asteroid]]s or othe