Europa, the fourth-largest moon of Jupiter, is a subject in both science fiction and scientific speculation for future human colonization. Europa's geophysical features, including a possible subglacial water ocean, make it a possibility that human life could be sustained on or beneath the surface.
Europa is thought to have a liquid water ocean underneath its icy exterior. Access to this liquid water ocean is a major difficulty, but the abundance of water on Europa is a benefit to any considerations for colonization. Not only can water provide for colonists' drinking needs, it also can be broken down to provide breathable oxygen. Oxygen is also believed to have accumulated from radiolysis of the ice on the surface that has been convected into the subsurface ocean and may prove sufficient for oxygen-using marine life.
The colonization of Europa presents numerous difficulties. One is the high level of radiation from Jupiter's radiation belt, which is about 10 times as strong as Earth's Van Allen radiation belts. Europa receives 5.4 Sv (540 rem) of radiation per day, which is approximately 1,800 times the average annual (yearly) dose of a human on earth at sea level. Humans exposed to this level of radiation for one day would have greater than 50% mortality rate within 30 days. Consequently, a human would require significant radiation shielding to survive at or near the surface of Europa. Colonists on Europa would have to descend beneath the surface when Europa is not protected by Jupiter's magnetotail, and stay in subsurface habitats. This would allow colonists to use Europa's ice sheet to shield themselves from radiation.
Another problem is that the surface temperature of Europa normally rests at −170 °C (103 K; −274 °F). However, the fact that liquid water is believed to exist below Europa's icy surface, along with the likelihood that colonists would spend much of their time under the ice sheet in order to shield themselves from radiation, may somewhat mitigate the problems associated with low surface temperatures.
The low gravity of Europa may also present challenges to colonization efforts. The effects of low gravity on human health are still an active field of study, but can include symptoms such as loss of bone density, loss of muscle density, and a weakened immune system. Astronauts in Earth orbit have remained in microgravity for up to a year and more at a time. Effective countermeasures for the negative effects of low gravity are well-established, particularly an aggressive regimen of daily physical exercise. The variation in the negative effects of low gravity as a function of different levels of low gravity are not known, since all research in this area is restricted to humans in zero gravity. The same goes for the potential effects of low gravity on fetal and pediatric development. It has been hypothesized that children born and raised in low gravity would not be well adapted for life under the higher gravity of Earth.
It is also speculated that alien organisms may exist on Europa, possibly in the water underlying the moon's ice shell. If this is true, human colonists may come into conflict with harmful microbes. More recent studies have indicated that the action of solar radiation on the surface of Europa might produce oxygen, which could be pulled down into the subsurface ocean by upwellings of the interior. If this process occurs, Europa's subsurface ocean could have an oxygen content equal to or greater than that of the Earth's.
An unstable surface could represent another potential problem. It has been shown that the moon is geologically active, with an outer crust showing plate tectonics which resembles that on Earth. The reconstruction of the geological activity over a few years of an area the size of the state Alabama showed that a piece of the surface as big as Massachusetts had moved down underneath the crust and disappeared.
Artemis Project colonization plan
In 1997, the Artemis Project produced a plan to colonize Europa. According to this plan, explorers would first establish a small base on the surface. From there, they would drill down into the Europan ice crust, entering the postulated subsurface ocean. The colonists would then create (or, possibly, find) a pocket between the icy surface and the liquid interior in which to establish a base. This location would be protected from radiation by the ice overhead, and would be at a more human-suitable temperature than the surface, as indicated by the presence of liquid water.
- Europa plays a role in the book and film of Arthur C. Clarke's 2010: Odyssey Two and its sequels. Highly-advanced aliens aiding the development of life take an interest in the primitive life forms under Europa's ice. They transform Jupiter into a star to kick-start their evolution, and forbid humans from landing on or colonizing Europa. In 2061: Odyssey Three, Europa has become a tropical ocean world.
- In Bruce Sterling's novel Schismatrix, Europa is inhabited by genetically engineered posthumans.
- Alastair Reynolds's short story A Spy in Europa depicts an advanced human society called the Demarchists, who are based in colonies on Europa that mainly cling to the underside of the ice crust at the surface of the ocean. A race of genetically altered humans adapted to live in the subsurface ocean is also created, some of whom later appear in Reynolds's 2006 short story "Grafenwalder's Bestiary."
- Europa is one of multiple satellites that is colonized in the Japanese animation Cowboy Bebop, along with Io, Ganymede, Callisto, and Titan.
- In Call of Duty: Infinite Warfare, Europa houses a military installation used as a black site for weapons development.
- In Warframe, Europa is under the alignment of the Corpus faction. It is depicted as an ice-covered planetoid and mining efforts by the Corpus are aided with machines and "heat generators" in open areas. It is also home to several black sites for creation of prototype weapon systems like the Raptors and other advanced robotic proxies.
- In the video game Barotruma, Europa has many research centers and colonies, as well as monsters, parasites, and other native lifeforms, in its subsurface ocean.
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