Editing Space colonization (section)

==Challenges to overcome==
Colonization beyond the Earth involves overcoming a number of difficult challenges.
===Distance from [[Earth]]===
The outer planets are much farther from Earth than the inner planets, and would therefore be harder and more time-consuming to reach. In addition, return voyages may well be prohibitive considering the time and distance. Even communication with Earth would be slow, with delays of 4 - 24 minutes for a message to [[mars]],<ref>{{Cite web |date=26 February 2024 |title=Communication Delays: The Hidden Challenge of Space Exploration - New Space Economy |url=https://newspaceeconomy.ca/2024/02/26/communication-delays-the-hidden-challenge-of-space-exploration/ |access-date=10 April 2025 |website=newspaceeconomy.ca |language=en-US}}</ref> and 35 - 52 minutes to Jupiter and it's moons.<ref>{{Cite web |date=15 August 2023 |title=NASA's Europa Probe Gets a Hotline to Earth |url=https://www.nasa.gov/missions/europa-clipper/nasas-europa-probe-gets-a-hotline-to-earth/ |website=NASA |access-date=19 April 2025 |language=en-US}}</ref>
===Extreme environments===
Extreme cold – due to the distance to the sun, temperatures are near [[absolute zero]] in many parts of the outer Solar System.<ref>{{Cite book |url=https://books.google.com/books?id=0bEMAwAAQBAJ |title=Encyclopedia of the solar system |date=1999 |publisher=Elsevier |location=San Diego |isbn=9780124160347 |first1=Doris |last1=Breuer |first2=Tilman |last2=Spohn |first3=Torrence |last3=Johnson}}</ref><ref>{{Cite journal |last1=Rathbun |first1=J. A. |last2=Spencer |first2=J. R. |last3=Tamppari |first3=L. K. |last4=Martin |first4=T. Z. |last5=Barnard |first5=L. |last6=Travis |first6=L. D. |date=1 May 2004 |title=Mapping of Io's thermal radiation by the Galileo photopolarimeter–radiometer (PPR) instrument |url=https://linkinghub.elsevier.com/retrieve/pii/S0019103504000235 |journal=Icarus |series=Special Issue: Io after Galileo |volume=169 |issue=1 |pages=127–139 |doi=10.1016/j.icarus.2003.12.021 |issn=0019-1035|url-access=subscription }}</ref>

===Sustainable power sources===
Power – [[Solar power]] is many times less concentrated in the outer Solar System than in the inner Solar System. It is unclear as to whether it would be usable there, using some form of concentration mirrors, or whether [[nuclear power]] would be necessary.<ref>{{cite journal|title=Study of Power Options for Jupiter and Outer Planet Missions |first1=Geoffrey A. |last1=Landis |first2=James |last2=Fincannon |url=https://ntrs.nasa.gov/api/citations/20160004679/downloads/20160004679.pdf |journal=42nd IEEE Photovoltaic Specialists Conference |location=New Orleans LA |date=19 June 2015|access-date=18 April 2025}}</ref> Use of geothermal systems to generate power may be practical on some of the planets and moons of the solar system.<ref>{{cite web|title=Geothermal Energy on Solar System Bodies |date=21 December 2022 |first=Ken |last=Wisian |url=https://www.beg.utexas.edu/news/geothermal-energy-on-solar-system-bodies |website = University of Texas |access-date=18 April 2025}}</ref>

===Physical and mental health risks to colonists===
{{main|Effect of spaceflight on the human body}}
The health of the humans who may participate in a colonization venture would be subject to increased physical, mental and emotional risks.
* [[Effect of spaceflight on the human body#Weightlessness|Effects of low gravity on the human body]] – All moons of the gas giants and all outer dwarf planets have a very low gravity, the highest being [[Io (moon)|Io's]] gravity (0.183 g) which is less than 1/5 of the Earth's gravity. Since the [[Apollo program]] all crewed spaceflight has been constrained to low Earth orbit and there has been no opportunity to test the effects of such low gravitational accelerations on the human body. It is speculated (but not confirmed) that the low gravity environments might have very similar effects to long-term exposure in [[weightlessness]]. Such effects might be avoided by [[Artificial gravity#Centripetal force|rotating spacecraft creating artificial gravity]].
* Dust – breathing risks associated with fine dust from rocky surface objects, for similar reasons as [[Lunar soil#Harmful effects of lunar dust|harmful effects of lunar dust]].<ref>{{Cite web |last=Dzombak |first=Rebecca |date=14 March 2025 |title=Martian Dust Will Be a Health Hazard for Astronauts |url=https://eos.org/research-spotlights/martian-dust-will-be-a-health-hazard-for-astronauts |access-date=10 April 2025 |website=Eos |language=en-US}}</ref>
* [[NASA]] learned that &ndash; without gravity &ndash; bones lose [[mineral (nutrient)|mineral]]s, causing [[osteoporosis]].<ref>{{Cite news|url=https://www.bbc.com/news/world-42627341|title=Here's what happens to your body in space|newspaper=BBC News|date=10 January 2018|access-date=9 April 2019 |language=en-GB|archive-url=https://web.archive.org/web/20190411152723/https://www.bbc.com/news/world-42627341|archive-date=11 April 2019|url-status=live}}</ref> [[Bone density]] may decrease by 1% per month,<ref name="nasa-body">{{Cite web|url=http://www.nasa.gov/hrp/bodyinspace|title=The Human Body in Space|last1=Abadie |first1=LJ |last2=Lloyd |first2=CW |last3=Shelhamer |first3=MJ|date=11 June 2018|publisher=NASA|access-date=4 March 2019 |archive-url=https://web.archive.org/web/20190726081140/https://www.nasa.gov/hrp/bodyinspace/|archive-date=26 July 2019|url-status=live}}</ref> which may lead to a greater risk of osteoporosis-related fractures later in life. Fluid shifts towards the head may cause vision problems.<ref>{{Cite news |last=Silverman |first=Lauren |date=4 March 2017 |title=Doctor Launches Vision Quest To Help Astronauts' Eyeballs |url=https://www.npr.org/sections/health-shots/2017/03/04/518214299/doctor-launches-vision-quest-to-help-astronauts-eyeballs |url-status=live |archive-url=https://web.archive.org/web/20190305165258/https://www.npr.org/sections/health-shots/2017/03/04/518214299/doctor-launches-vision-quest-to-help-astronauts-eyeballs |archive-date=5 March 2019 |access-date=7 March 2019 |website=NPR.org}}</ref> 
* NASA found that isolation in closed environments aboard the [[International Space Station]] led to [[Depression (mood)|depression]], [[sleep disorder]]s, and diminished personal interactions, likely due to confined spaces and the monotony and boredom of long space flight.<ref name=nasa-body/><ref>{{Cite web |last=Stuster |first=Jack W. |title=NASA - Behavioral Issues Associated with isolation and Confinement: Review and Analysis of Astronaut Journals |url=https://www.nasa.gov/mission_pages/station/research/experiments/991.html |url-status=live |archive-url=https://web.archive.org/web/20190411152721/https://www.nasa.gov/mission_pages/station/research/experiments/991.html |archive-date=11 April 2019 |access-date=9 April 2019 |publisher=NASA}}</ref> 
* [[Circadian rhythm]] may also be susceptible to the effects of space life due to the effects on sleep of disrupted timing of sunset and sunrise.<ref name="weir">{{Cite web |last=Weir |first=Kirsten |date=1 June 2018 |title=Mission to Mars |url=https://www.apa.org/monitor/2018/06/mission-mars |url-status=live |archive-url=https://web.archive.org/web/20191212130533/https://www.apa.org/monitor/2018/06/mission-mars |archive-date=12 December 2019 |access-date=4 March 2019 |publisher=American Psychological Association |quote=We are a circadian species, and if you don't have the proper lighting to maintain that [[chronobiology]], it can create significant problems for crew members}}</ref> This can lead to exhaustion, as well as other sleep problems such as [[insomnia]], which can reduce their productivity and lead to mental health disorders.<ref name=weir/> High-energy radiation is a health risk that colonists would face, as radiation in deep space is deadlier than what astronauts face now in low Earth orbit. Metal shielding on space vehicles protects against only 25–30% of space radiation, possibly leaving colonists exposed to the other 70% of radiation and its short and long-term health complications.<ref name=":0"/>