Colonization of the outer Solar System 1860054 224949323 2008-07-11T03:49:45Z Tom 94202 /* The Jovian system */ reword {{Refimprove|date=February 2007}} {{Space colonization}} Some of the moons of the outer planets of the [[solar system]] are large enough to be suitable places for colonization. Many of the larger moons contain [[Ice|water ice]], [[liquid water]], and [[organic compound]]s that might be useful for sustaining human life. Colonies in the outer solar system could also serve as centers for long term investigation of the planet and the other moons. In particular, robotic devices could be controlled by humans without the very long time delays needed to communicate with [[Earth]]. There have also been proposals to place robotic [[aerostat]]s in the upper atmospheres of the gas giant planets for exploration and possibly mining of [[helium-3]], which could have a very high value per unit mass as a thermonuclear fuel.<ref name="zoob2sop">Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: Settling the Outer Solar System: The Sources of Power, pp. 158-160, Tarcher/Putnam, 1999, ISBN 1-58542-036-0</ref><ref name="He3U">Jeffrey Van Cleve (Cornell University) et al., [http://www.mines.edu/research/srr/2001abstracts/vancleve.PDF "Helium-3 Mining Aerostats in the Atmosphere of Uranus"], Abstract for Space Resources Roundtable, accessed May 10, 2006</ref> ==The Jovian system== The [[Jupiter|Jovian]] system in general poses particular disadvantages for colonizing because of its severe radiation environment and its particularly deep [[gravity well]]. Its radiation would deliver about 3,600 [[Radiation poisoning#Table of exposure levels and symptoms|rems]] per day to unshielded colonists at [[Io (moon)|Io]] and about 540 rems per day to unshielded colonists at Europa. Exposure of approximately 75 rems over a period of a few days is enough to cause radiation poisoning, and about 500 rems over a few days is fatal.<ref name="zoob2jvn">Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: Colonizing the Jovian System, pp. 166-170, Tarcher/Putnam, 1999, ISBN 1-58542-036-0</ref> ===Jupiter=== {{Main|Colonization of Jupiter}} Jupiter could be the site of airborne colonies such as [[floating cities]], assuming the radiation and gravity issues in traveling to and from the atmosphere are properly addressed. Jupiter has an atmospheric depth with the same pressure as Earth sea level, where there is also a blue sky, though it is colder than on Earth; further down, Jupiter has an atmospheric depth that is the same average temperature as the surface of the Earth, where the pressure is about five bars. One significant challenge to overcome in colonizing Jupiter would be the intense radiation in the planet's [[Jupiter's magnetosphere|magnetosphere]]. ===Europa=== {{Main|Colonization of Europa}} The [[Artemis Project]] designed a plan to colonize [[Europa (moon)|Europa]].<ref>[http://www.asi.org/ Artemis Society International] official website</ref><ref>Peter Kokh et al., "[http://asi.org/adb/06/09/03/02/110/europa2-wkshp.html Europa II Workshop Report]", ''Moon Miner's Manifesto'' #110, Nov. 1997</ref> Scientists are to inhabit igloos and drill down into the Europan ice crust, exploring any sub-surface ocean. It also discusses use of [[Air Pocket|air pockets]] for human inhabitation. ===Ganymede=== [[Ganymede (moon)|Ganymede]] is the largest moon in the Solar System, making it a possible target for colonization. Ganymede is also the only moon with a [[magnetosphere]]. ===Callisto=== {{Main|Colonization of Callisto}} [[NASA]] performed a study called ''HOPE'' (Revolutionary Concepts for '''H'''uman '''O'''uter '''P'''lanet '''E'''xploration) regarding the future exploration of the solar system.<ref>Patrick A. Troutman (NASA Langley Research Center) et al., [http://rasc.larc.nasa.gov/rasc_new/hope/Documents/HOPE_Paper.doc Revolutionary Concepts for Human Outer Planet Exploration (HOPE)], accessed May 10, 2006 (.doc format)</ref> The target chosen was [[Callisto (moon)|Callisto]]. It could be possible to build a surface base that would produce fuel for further exploration of the solar system. ===Trojan asteroids=== The 2006 [http://www.berkeley.edu/news/media/releases/2006/02/01_patroclus.shtml announcement] by the [[Keck Observatory]] that the binary [[Trojan asteroid]] [[617 Patroclus]], and possibly large numbers of other Trojan objects in Jupiter's orbit, are likely composed of water ice, with a layer of dust, suggests that mining water and other volatiles in this region and transporting them elsewhere in the Solar system, perhaps via the proposed [[Interplanetary Transport Network]], may be feasible in the not-so-distant future. This could make colonization of the [[colonization of the Moon|Moon]], [[Colonization of Mercury|Mercury]] and main-belt [[Colonization of the asteroids|asteroids]] more practical. ==The Saturnian system== [[Robert Zubrin]] identified [[Saturn]], [[Uranus]] and [[Neptune]] as "the [[Persian Gulf]] of the solar system", as the largest sources of deuterium and helium-3 to drive the pending [[nuclear fusion|fusion]] economy, with Saturn the most important and most valuable of the three, because of its relative proximity, low radiation, and excellent system of moons.<ref name="zoob2pgs">Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: The Persian Gulf of the solar system, pp. 161-163, Tarcher/Putnam, 1999, ISBN 1-58542-036-0</ref> ===Titan=== {{main|Colonization of Titan}} <!-- This may be the one Colonization article that is merged, into this article. See discussion. --> Robert Zubrin identified [[Titan (moon)|Titan]] as possessing an abundance of all the elements necessary to support life, making Titan perhaps the most advantageous locale in the outer Solar System for colonization, and saying "In certain ways, Titan is the most hospitable extraterrestrial world within our solar system for human colonization."<ref name="zoob2ttn">Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: Titan, pp. 163-166, Tarcher/Putnam, 1999, ISBN 1-58542-036-0</ref> The surface of Titan is mostly uncratered and thus inferred to be very young and active, and probably composed of mostly water ice, and lakes of liquid hydrocarbons (methane/ethane) in its polar regions. While the temperature is cryogenic (95 K) it should be able to support a base, but more information regarding Titan's surface and the activities on it is necessary. The thick atmosphere and the weather, such as potential flash floods, are also factors to consider. Incidentally, a widely published expert on [[terraforming]], [[Christopher McKay]], is also a co-investigator on the [[Huygens probe]] that landed on Titan in January 2005. ===Enceladus=== On March 9th, 2006, [[NASA]]'s [[Cassini-Huygens|Cassini]] space probe found possible evidence of liquid water on [[Enceladus (moon)|Enceladus]].<ref>[http://www.nasa.gov/mission_pages/cassini/media/cassini-20060309.html NASA - NASA's Cassini Discovers Potential Liquid Water on Enceladus<!-- Bot generated title -->]</ref> According to that article, "pockets of liquid water may be no more than tens of meters below the surface." If these findings are confirmed, it would mean liquid water could be collected much more easily on Enceladus than on, for instance, Europa (see above). Discovery of water, especially liquid water, generally improves a celestial body's consideration for colonization dramatically. An alternative model of Enceladus' activity is the decomposition of methane/water clathrates - a process requiring lower temperatures than liquid water eruptions. The relatively higher density of Enceladus indicates a larger than Saturnian average silicate core that should provide materials for base operations. ==Uranus== Because [[Uranus]] has the lowest [[escape velocity]] of the four gas giants, it has been proposed as a mining site for [[helium-3]].<ref name="He3U"/> If human supervision of the robotic activity proved necessary, one of [[Uranus' natural satellites]] might serve as a base. An alternative is to place [[Floating cities (science fiction)|floating cities]] in its atmosphere. By using balloons filled with [[hydrogen]], large masses can be suspended{{Fact|date=February 2007}} underneath at roughly [[Earth]] gravity. Saturn and Neptune could be suitable as well, but [[Jupiter]] would likely not be, due to its high gravity, escape velocity, and radiation. ==Neptune== [[Neptune]] and its satellites could also be used for colonization, but are farther away, and Neptune has a higher surface gravity than Uranus. Its satellites, especially [[Triton (moon)|Triton]], could also be colonized. Triton's surface shows signs of extensive geological activity implying a sub-surface ocean, perhaps of ammonia/water<ref>{{cite journal|last=Ruiz |first=Javier| year=2003| title=Heat flow and depth to a possible internal ocean on Triton| journal=Icarus| volume=166| doi=10.1016/j.icarus.2003.09.009| pages=436}}</ref>. Such geothermal energy would make colonising a cryogenic world like Triton feasible. ==Kuiper Belt and Oort Cloud== :''See also [[Colonization of Trans-Neptunian Objects]] The noted [[physicist]] [[Freeman Dyson]] identified [[comet]]s, rather than [[planet]]s, as the major potential ''habitat'' of life in space.<ref>Freeman Dyson, "The World, the Flesh, and the Devil", Third J.D. Bernal Lecture, May 1972, reprinted in ''Communication with Extraterrestrial Intelligence'', [[Carl Sagan]], ed., MIT Press, 1973, ISBN 0-262-69037-3</ref> ==Challenges== There are various difficulties in colonizing the outer solar system. They include: *Distance from [[Earth]]: The outer planets are much further from Earth than inner planets, and would therefore be harder and more time-consuming to reach. *Planetary conditions: The outer planets have no surface to land on, so any habitation would have to use floating colonies, increasing complexity and decreasing reliability. The moons/comets do not have this problem, although some have specific problems (ie., [[Europa (moon)|Europa]] is in [[Jupiter]]'s intense radiation bands). *Power: [[Solar power]] is generally considered unsuitable because of the large distance from the [[sun]]. [[Nuclear power]] is believed to be the only suitable power source for the colonies. ==See also== *[[Floating cities (science fiction)|Floating cities]] *[[Solar System in fiction]] ==References== <div class="references-small"><references/></div> [[Category:Space colonization]] [[fr:Colonisation du système solaire externe]] [[it:Colonizzazione del sistema solare esterno]] [[ja:外部太陽系の植民]] [[pt:Colonização do Sistema Solar]] [[ru:Колонизация внешних объектов Солнечной системы]] [[sv:Kolonisering av de yttre planeterna]]