Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...

's largest moon

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

is one of several candidates for possible future

colonization of the outer Solar System Many planets within the Solar System have been considered for colonization and terraforming. The main candidates for colonization in the inner Solar System are Mars and Venus. Other possible candidates for colonization include the Moon and eve ...

, though protection against extreme cold is a major consideration. According to ''Cassini'' data from 2008, Titan has hundreds of times more liquid

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

s than all the known oil and natural gas reserves on Earth. These hydrocarbons rain from the sky and collect in vast deposits that form lakes and dunes.Findings from the study led by Ralph Lorenz, Cassini radar team member from the Johns Hopkins University Applied Physics Laboratory, USA, are reported in the 29 January 2008 issue of the Geophysical Research Letters. "Titan is just covered in carbon-bearing material—it's a Mega factory of

organic chemicals In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The s ...

", said Ralph Lorenz, who leads the study of Titan based on radar data from Cassini. "This vast carbon inventory is an important Look into the geology and climate history of Titan." Several hundred lakes and seas have been observed, with several dozen estimated to contain more hydrocarbon liquid than Earth's oil and gas reserves. The dark dunes that run along the equator contain a volume of organics several hundred times larger than Earth's coal reserves. PIA09184 -Titan Sea and Lake Superior

Radar images obtained on July 21, 2006 appear to show lakes of liquid hydrocarbon (such as

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...

and

ethane Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petroc ...

) in Titan's northern latitudes. This is the first discovery of currently existing lakes beyond Earth. The lakes range in size from about a kilometer in width to one hundred kilometers across. On March 13, 2007, the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, La Cañada Flintridge, California ...

announced that it found strong evidence of

sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...

s of methane and ethane in the northern hemisphere. At least one of these is larger than any of the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

Suitability

The American aerospace engineer and author

Robert Zubrin Robert Zubrin (; born April 9, 1952) is an American aerospace engineer, author, and advocate for human exploration of Mars. He and his colleague at Martin Marietta, David Baker, were the driving force behind Mars Direct, a proposal in a 1990 res ...

identified Saturn as the most important and valuable of the four

gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...

s in the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

, because of its relative proximity, low radiation, and excellent system of moons. He also named Titan as the most important moon on which to establish a base to develop the resources of the Saturn system.Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: The Persian Gulf of the solar system, pp. 161-163, Tarcher/Putnam, 1999,

Habitability

has pointed out that Titan possesses an abundance of all the elements necessary to support life, saying "In certain ways, Titan is the most hospitable extraterrestrial world within our solar system for human colonization."Robert Zubrin, ''Entering Space: Creating a Spacefaring Civilization'', section: Titan, pp. 163-166, Tarcher/Putnam, 1999, The atmosphere contains plentiful

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and

. Additionally, strong evidence indicates that liquid methane exists on the surface. Evidence also indicates the presence of liquid

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

under the surface, which are delivered to the surface by

volcanic activity Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

. While this water can be used to generate breathable

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...

, more is blown into Titan's atmosphere from the geysers on the icy moon of

Enceladus Enceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most refle ...

(also a moon of Saturn), as they start as water molecules and evolve into oxygen and

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...

. Nitrogen is ideal to add

buffer gas A buffer gas is an inert or nonflammable gas. In the Earth's atmosphere, nitrogen acts as a buffer gas. A buffer gas adds pressure to a system and controls the speed of combustion with any oxygen present. Any inert gas such as helium, neon, ...

partial pressure to breathable air (it forms about 78% of

Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...

).Robert Zubrin, '' The Case for Mars: The Plan to Settle the Red Planet and Why We Must'', p. 146, Simon & Schuster/Touchstone, 1996, Nitrogen, methane and ammonia can all be used to produce

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

for growing food.

Gravity

Titan has a surface gravity of 0.138 ''g'', slightly less than the Moon. Managing long-term effects of low gravity on human health would therefore be a significant issue for long-term occupation of Titan, more so than on Mars. These effects are still an active field of study. They can include symptoms such as loss of bone density, loss of muscle density, and a weakened

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...

Astronaut An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally r ...

s in Earth orbit have remained in microgravity for up to a year or more at a time. Effective countermeasures for the negative effects of low gravity are well-established, particularly an aggressive regimen of daily physical exercise or weighted clothing. 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 such as on Titan would not be well adapted for life under the higher gravity of Earth.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,

In situ energy resources

In situ energy resources on Titan for use by future humans include chemical, nuclear, wind, solar and hydropower. Electrical power could be produced using chemical power plants adding hydrogen to acetylene (i.e. hydrogenation; oxygen is not freely available), or turbines in large methane seas such as Kraken Mare where the tidal pull of Saturn causes up to a meter of tidal change each Titan day. Nuclear and solar power might also be feasible.

Flight

The very high ratio of atmospheric density to surface gravity also greatly reduces the wingspan needed for an aircraft to maintain lift, so much so that a human would be able to strap on wings and easily fly through Titan's atmosphere while wearing a sort of spacesuit that could be manufactured with today's technology. Another theoretically possible means to become airborne on Titan would be to use a

hot air balloon A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries ...

-like vehicle filled with an Earth-like atmosphere at Earth-like temperatures (because oxygen is only slightly denser than nitrogen, the atmosphere in a habitat on Titan would be about one third as dense as the surrounding atmosphere), although such a vehicle would need a skin able to keep the extreme cold out in spite of the light weight required. Due to Titan's extremely low temperatures, heating of any flight-bound vehicle becomes a key obstacle.

Suitability

Habitability

Gravity

In situ energy resources

Flight

See also

References

Further reading