Editing Space colonization (section)

====Jovian moons====
[[File:Callisto base.PNG|thumb|upright=1.2|Artist's impression of a base on Callisto<ref name="CallistoBase">{{cite web|title=Vision for Space Exploration|url=http://www.nasa.gov/pdf/55583main_vision_space_exploration2.pdf|publisher=[[NASA]]|year=2004}}</ref>]]
<div style="float:right; margin:2px;">
{| class=wikitable style="text-align:center; font-size:11px"
|+ Jovian radiation
! Moon !! [[Röntgen equivalent man|rem]]/day
|-
| Io || 3600<ref name="ringwald">{{cite web |date=29 February 2000 |title=SPS 1020 (Introduction to Space Sciences) |publisher=California State University, Fresno |last=Ringwald |first=Frederick A. |url=https://zimmer.csufresno.edu/~fringwal/w08a.jup.txt |url-status=dead |access-date=5 January 2014 |archive-url=https://web.archive.org/web/20080725050708/https://zimmer.csufresno.edu/~fringwal/w08a.jup.txt |archive-date=25 July 2008 }}</ref>
|-
| Europa || 540<ref name="ringwald"/>
|-
|Ganymede || 8<ref name="ringwald"/>
|-
| Callisto || 0.01<ref name="ringwald"/>
|-
! Earth (Max) !!  0.07
|-
! Earth (Avg) !! 0.0007

|}</div>

The [[Jupiter|Jovian]] system in general has particular disadvantages for colonization, including a deep [[gravity well]]. The [[magnetosphere of Jupiter]] bombards the [[moons of Jupiter]] with intense [[ionizing radiation]]<ref name="radjup">{{cite journal|first1=R. Walker |last1=Fillius |first2=Carl E. |last2=McIlwain |first3=Antonio |last3=Mogro-Campero |title=Radiation Belts of Jupiter: A Second Look |journal=Science |volume=188 |number=4187 |pages=465–467 |date=2 May 1975 |doi=10.1126/science.188.4187.465 |pmid=17734363 |url=https://www.science.org/doi/10.1126/science.188.4187.465}}</ref> delivering about 36 [[Sievert#Dose examples|Sv]] per day to unshielded colonists on [[Io (moon)|Io]] and about 5.40 Sv per day on [[Europa (moon)|Europa]]. Exposure to about 0.75 Sv over a few days is enough to cause [[Acute radiation syndrome|radiation poisoning]], and about 5&nbsp;Sv over a few days is fatal.<ref name="zubrin1999"/>{{rp|166–170}}

Jupiter itself, like the other gas giants, has further disadvantages. There is no accessible surface on which to land, and the light hydrogen atmosphere would not provide good buoyancy for some kind of aerial habitat as has been proposed for Venus.

Radiation levels on [[Io (moon)|Io]] and [[Europa (moon)|Europa]] are extreme, enough to kill unshielded humans within an Earth day.<ref name="zubrin1999">{{cite book |first=Robert |last=Zubrin |title=Entering Space: Creating a Spacefaring Civilization |publisher=Tarcher/Putnam |date=1999 |isbn=978-1-58542-036-0|url=https://books.google.com/books?id=67XuAAAAMAAJ |access-date=18 April 2025}}</ref>{{rp|163–170}} Therefore, only [[Callisto (moon)|Callisto]] and perhaps [[Ganymede (moon)|Ganymede]] could reasonably support a human colony. Callisto orbits outside Jupiter's radiation belt.<ref name=Kerwick/> Ganymede's low latitudes are partially shielded by the moon's magnetic field, though not enough to completely remove the need for radiation shielding. Both of them have available water, silicate rock, and metals that could be mined and used for construction.<ref name=Kerwick/>

Although Io's volcanism and tidal heating constitute valuable resources, exploiting them is probably impractical.<ref name=Kerwick>{{cite journal |last1=Kerwick |first1=Thomas B. |date=2012 |title=Colonizing Jupiter's Moons: An Assessment of Our Options and Alternatives |url=https://www.jstor.org/stable/24536505 |journal=Journal of the Washington Academy of Sciences |volume=98 |issue=4 |pages=15–26 |jstor=24536505 |access-date=1 August 2021}}</ref> Europa is rich in water (its subsurface ocean is expected to contain over twice as much water as all Earth's oceans together)<ref name=UTJupiter/> and likely oxygen, but metals and minerals would have to be imported. If alien microbial life exists on Europa, human immune systems may not protect against it. Sufficient radiation shielding might, however, make Europa an interesting location for a research base.<ref name=Kerwick/> The private ''[[Artemis Project]]'' drafted a plan in 1997 to colonize Europa, involving surface igloos as bases to drill down into the ice and explore the ocean underneath, and suggesting that humans could live in "air pockets" in the ice layer.<ref>[http://www.asi.org/ Artemis Society International], {{Webarchive|url=https://web.archive.org/web/20110820180833/http://asi.org/|date=20 August 2011}} official website.</ref><ref>{{cite journal|first1=Peter |last1=Kokh |first2=Mark |last2=Kaehny |first3=Doug |last3=Armstrong |first4=Ken |last4=Burnside |url=http://asi.org/adb/06/09/03/02/110/europa2-wkshp.html |title=Europa II Workshop Report |archive-url=https://web.archive.org/web/20190607102248/http://asi.org/adb/06/09/03/02/110/europa2-wkshp.html|archive-date=7 June 2019 |journal=Moon Miner's Manifesto |volume=110 |date=November 1997}}</ref><ref name=UTJupiter>{{cite web |url=https://www.universetoday.com/130637/colonize-jupiters-moons/ |title=How do we Colonize Jupiter's Moons? |last=Williams |first=Matt |date=23 November 2016 |website=[[Universe Today]] |access-date=10 January 2022}}</ref> Ganymede<ref name=UTJupiter/> and Callisto are also expected to have internal oceans.<ref name='OW Roadmap 2019'>{{cite journal | last1 = Hendrix | first1 = Amanda R. | last2 = Hurford | first2 = Terry A. | last3 = Barge | first3 = Laura M. | last4 = Bland | first4 = Michael T. | last5 = Bowman | first5 = Jeff S. | last6 = Brinckerhoff | first6 = William | last7 = Buratti | first7 = Bonnie J. | last8 = Cable | first8 = Morgan L. | last9 = Castillo-Rogez | first9 = Julie | last10 = Collins | first10 = Geoffrey C. | display-authors = etal | year = 2019| title = The NASA Roadmap to Ocean Worlds | journal = Astrobiology | volume = 19| issue = 1 | pages = 1–27| doi = 10.1089/ast.2018.1955 | pmid = 30346215 | pmc = 6338575 | bibcode = 2019AsBio..19....1H | doi-access = free }}</ref> It might be possible to build a surface base that would produce fuel for further exploration of the Solar System.

In 2003, NASA performed a study called ''HOPE'' (Revolutionary Concepts for Human Outer Planet Exploration) regarding the future exploration of the Solar System.<ref>{{cite report|first1=Patrick A. |last1=Troutman |first2=Kristen |last2=Bethke |first3=Frederic H. |last3=Stillwagen |first4=Darrell L. |last4=Caldwell, Jr |first5=Ram |last5=Manvi |first6=Chris |last6=Strickland |first7=Shawn A. |last7=Krizan |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030063128.pdf |title=Revolutionary Concepts for Human Outer Planet Exploration (HOPE) |archive-url=https://web.archive.org/web/20170815051016/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030063128.pdf|archive-date=15 August 2017 |date=28 January 2003 |access-date= 19 April 2025|publisher=NASA Langley Research Center}}</ref> The target chosen was [[Callisto (moon)|Callisto]] due to its distance from Jupiter, and thus the planet's harmful radiation. It could be possible to build a surface base that would produce fuel for further exploration of the Solar System.<ref>{{cite book|last=Seedhouse|first=Erik|title=Interplanetary Outpost: The Human and Technological Challenges of Exploring the Outer Planets|year=2012 |url=https://books.google.com/books?id=Cf3N1ejDNO4C|publisher=Springer |location=Berlin |isbn=978-1-4419-9747-0|access-date=19 April 2025}}</ref>{{rp|21}} HOPE estimated a round trip time for a crewed mission of about 2–5 years, assuming significant progress in propulsion technologies.<ref name=Kerwick/>

[[Io (moon)|Io]] is not ideal for colonization, due to its hostile environment. The moon is under influence of high tidal forces, causing high volcanic activity. Jupiter's strong radiation belt overshadows Io, delivering 36 Sv a day to the moon. The moon is also extremely dry. Io is the least ideal place for the colonization of the four Galilean moons.
Despite this, its volcanoes could be energy resources for the other moons, which are better suited to colonization.

[[File:Currents in Jovian Magnetosphere.png|thumb|upright=2|The magnetic field of Jupiter and co-rotation rotation enforcing currents]]

[[Ganymede (moon)|Ganymede]] is the largest moon in the Solar System. Ganymede is the only moon with a [[magnetosphere]], albeit overshadowed by [[Magnetosphere of Jupiter|Jupiter's magnetic field]]. Because of this magnetic field, Ganymede is one of only two Jovian moons where surface settlements would be feasible because it receives about 0.08 [[Sievert|Sv]] of radiation per day. Ganymede could be terraformed.<ref name="ringwald"/>

The [[Keck Observatory]] announced in 2006 that the binary [[Jupiter trojan]] [[617 Patroclus]], and possibly many other Jupiter trojans, are likely composed of water ice, with a layer of dust. This 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 Moon]], [[Colonization of Mercury|Mercury]] and main-belt [[Colonization of the asteroids|asteroids]] more practical.