Colonization of Europa
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. As Europa receives 540 rem of radiation per day (500 rem is a fatal dose), a human would not survive at or near the surface of Europa for long without significant radiation shielding. 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) (-275°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, or aggressive native life forms. 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, possibly providing a home to more complex life.
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 reasonable temperature than the surface, as indicated by the presence of liquid water.
Colonization in fiction
- Europa plays a role in the book and film of Arthur C. Clarke's 2010: Odyssey Two and its sequels. Super-advanced aliens aiding the development of life take an interest in the primitive life forms under Europa's ice and 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."
- Chandler, D. L. (20 October 2002). "Thin ice opens lead for life on Europa". NewScientist.com.
- Frederick A. Ringwald (29 February 2000). "SPS 1020 (Introduction to Space Sciences)". California State University, Fresno. Retrieved 2009-09-20.
- Robert Zubrin, "Colonizing the Outer Solar System", in Islands in the Sky: Bold New Ideas for Colonizing Space, pp. 85-94, Stanley Schmidt and Robert Zubrin, eds., Wiley, 1996, ISBN 978-0-471-13561-6
- Jones, N. (11 December 2001). "Bacterial explanation for Europa's rosy glow". NewScientist.com.
- Nancy Atkinson (2009). "Europa Capable of Supporting Life, Scientist Says". Universe Today. Retrieved 2009-10-11.
- Kokh, Peter; Kaehny, Mark; Armstrong, Doug; Burnside, Ken (November 1997). "Europa II Workshop Report". Moon Miner's Manifesto (110).
- "Humans on Europa: A Plan for Colonies on the Icy Moon". Space.com. 6 June 2001. Retrieved 10 May 2006.