![NASA Cloud City on Venus](https://upload.wikimedia.org/wikipedia/commons/e/e8/NASA_Cloud_City_on_Venus.jpg)
The colonization of Venus has been a subject of many works of
science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel unive ...
since before the dawn of
spaceflight
Spaceflight (or space flight) is an application of astronautics to fly spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in or ...
, and is still discussed from both a fictional and a scientific standpoint. However, with the discovery of
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
's extremely hostile surface environment, attention has largely shifted towards the
colonization of the Moon
Colonization of the Moon or Lunar settlement is a process, or concept employed by some proposals, for claiming robotic or human exploitation and settlement on the Moon.
Laying claim to the Moon has been declared illegal through international ...
and
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
instead, with proposals for Venus focused on habitats floating in the upper-middle atmosphere and on
terraforming
Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make ...
.
Background
Space colonization is a step beyond
space exploration
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by robotic spacec ...
, and implies the permanent or long-term presence of humans in an environment outside
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
. Colonization of space was claimed by Stephen Hawking to be
the best way to ensure the survival of
humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
as a species. Other reasons for colonizing space include economic interests, long-term scientific research best carried out by humans as opposed to robotic probes, and sheer curiosity. Venus is the second largest
terrestrial planet
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Ve ...
and Earth's closest neighbor, which makes it a potential target.
With discoveries as of 2020 of
traces of possibly indigenous life in the
atmosphere of Venus, attempts of any
humanization of Venus have become an increased issue of
planetary protection
Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions. Planetary protection refle ...
, since uncontrolled effects of
human presence might endanger such life.
Advantages
![Venus Earth Comparison](https://upload.wikimedia.org/wikipedia/commons/2/2d/Venus_Earth_Comparison.png)
Venus has certain similarities to
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
which, if not for the hostile conditions, might make colonization easier in many respects in comparison with other possible destinations. These similarities, and its proximity, have led Venus to be called Earth's "sister planet".
At present it has not been established whether the
gravity of Mars
The gravity of Mars is a natural phenomenon, due to the law of gravity, or gravitation, by which all things with mass around the planet Mars are brought towards it. It is weaker than Earth's gravity due to the planet's smaller mass. The average ...
, 0.38 times that of the Earth, would be sufficient to avoid
bone decalcification Bone decalcification is the softening of bones due to the removal of calcium ions, and can be performed as a histological technique to study bones and extract DNA. This process also occurs naturally during bone development and growth, and when uninh ...
and loss of muscle tone experienced by astronauts living in a
micro-g environment
The term micro-g environment (also μg, often referred to by the term microgravity) is more or less synonymous with the terms ''weightlessness'' and ''zero-g'', but emphasising that g-forces are never exactly zero—just very small (on the I ...
. In contrast, Venus is close in size and mass to the Earth, resulting in a similar surface gravity (0.904
''g'') that would likely be sufficient to prevent the health problems associated with
weightlessness
Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G.
Weight is a measurement of the force on an object at rest in a relatively strong gravitational fi ...
. Most other space exploration and colonization plans face concerns about the damaging effect of long-term exposure to fractional ''g'' or
zero gravity
Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G.
Weight is a measurement of the force on an object at rest in a relatively strong gravitational f ...
on the human
musculoskeletal system
The human musculoskeletal system (also known as the human locomotor system, and previously the activity system) is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system provid ...
.
Venus's relative proximity makes transportation and communications easier than for most other locations in the
Solar System
The Solar SystemCapitalization 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 S ...
. With current propulsion systems,
launch window
In the context of spaceflight, launch period is the collection of days and launch window is the time period on a given day during which a particular rocket must be launched in order to reach its intended target. If the rocket is not launched wit ...
s to Venus occur every 584 days,
compared to the 780 days for Mars.
[David S. F. Portree, ''Humans to Mars: Fifty Years of Mission Planning, 1950–2000,'' NASA Monographs in Aerospace History Series, Number 21, February 2001. Available a]
NASA SP-2001-4521
Flight time is also somewhat shorter; the
Venus Express
''Venus Express'' (VEX) was the first Venus exploration mission of the European Space Agency (ESA). Launched in November 2005, it arrived at Venus in April 2006 and began continuously sending back science data from its polar orbit around Venus. ...
probe that arrived at Venus in April 2006 spent slightly over five months en route, compared to nearly six months for
Mars Express
''Mars Express'' is a space exploration mission being conducted by the European Space Agency (ESA). The ''Mars Express'' mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally ref ...
. This is because at closest approach, Venus is from Earth (approximated by perihelion of Earth minus aphelion of Venus) compared to for Mars (approximated by perihelion of Mars minus aphelion of Earth) making Venus the closest planet to Earth.
Venus's atmosphere is made mostly out of carbon dioxide. Because
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
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 as wel ...
are lighter than carbon-dioxide, breathable-air-filled balloons will float at a height of about . At this height, the temperature is a manageable . At higher, it is a temperate (see ).
The atmosphere also provides the various elements required for human life and agriculture: carbon, hydrogen, oxygen, nitrogen, and sulfur.
Additionally, the upper atmosphere could provide protection from harmful solar
radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:
* ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
comparable to the protection provided by
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 for ...
. The
atmosphere of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and no ...
, as well as
the Moon
The Moon is Earth's only natural satellite. It is the List of natural satellites, fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth ( ...
provide little such protection.
Difficulties
Venus also presents several significant challenges to human colonization. Surface conditions on Venus are difficult to deal with: the
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
at the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
averages around , higher than the
melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...
of
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
, which is 327 °C. The
atmospheric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...
on the surface is also at least ninety times greater than on Earth, which is equivalent to the pressure experienced under a kilometer of water. These conditions have caused missions to the surface to be extremely brief: the Soviet
Venera 5 and
Venera 6 probes were crushed by high pressure while still 18 km above the surface. Following landers such as
Venera 7 and
Venera 8 succeeded in transmitting data after reaching the surface, but these missions were brief as well, surviving no more than a single hour on the surface.
![Venus from Mariner 10](https://upload.wikimedia.org/wikipedia/commons/0/08/Venus_from_Mariner_10.jpg)
Furthermore,
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 a ...
, in any form, is almost entirely absent from Venus. The
atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
is devoid of molecular
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 as wel ...
and is primarily
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
. In addition, the visible clouds are composed of corrosive
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
and
sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...
vapor.
Exploration and research
Over 20 successful space missions have visited Venus since 1962. The last European probe was
ESA
, owners =
, headquarters = Paris, Île-de-France, France
, coordinates =
, spaceport = Guiana Space Centre
, seal = File:ESA emblem seal.png
, seal_size = 130px
, image = Views in the Main Control Room (120 ...
's
Venus Express
''Venus Express'' (VEX) was the first Venus exploration mission of the European Space Agency (ESA). Launched in November 2005, it arrived at Venus in April 2006 and began continuously sending back science data from its polar orbit around Venus. ...
, which was in polar orbit around the planet from 2006 to 2014. A Japanese probe,
Akatsuki, failed in its first attempt to orbit Venus, but successfully reinserted itself into orbit on 7 December 2015. Other low-cost missions have been proposed to further explore the planet's atmosphere, as the area above the surface where gas pressure is at the same level as Earth has not yet been thoroughly explored.
Aerostat habitats and floating cities
![Venusballoonoutpost](https://upload.wikimedia.org/wikipedia/commons/6/62/Venusballoonoutpost.png)
At least as early as 1971
[.] Soviet scientists had suggested that rather than attempting to settle Venus' hostile surface, humans might attempt to settle the
Venusian atmosphere
The atmosphere of Venus is the layer of gases surrounding Venus. It is composed primarily of Supercritical carbon dioxide, supercritical carbon dioxide and is much denser and hotter than atmosphere of Earth, that of Earth. The temperature at the ...
.
Geoffrey A. Landis of NASA's
Glenn Research Center
NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facilit ...
has summarized the perceived difficulties in colonizing Venus as being merely from the assumption that a colony would need to be based on the surface of a planet:
Landis has proposed
aerostat
An aerostat (, via French) is a lighter-than-air aircraft that gains its lift through the use of a buoyant gas. Aerostats include unpowered balloons and powered airships. A balloon may be free-flying or tethered. The average density of the cra ...
habitats followed by
floating cities, based on the concept that breathable air (21:79 oxygen/nitrogen mixture) is a
lifting gas
A lifting gas or lighter-than-air gas is a gas that has a density lower than normal atmospheric gases and rises above them as a result. It is required for aerostats to create buoyancy, particularly in lighter-than-air aircraft, which include ballo ...
in the dense
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
atmosphere, with over 60% of the lifting power that
helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
has on Earth.
[; draft version o]
the full paper
available at NASA Technical Reports Server (accessed 16 May 2012) In effect, a
balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...
full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of above the Venusian surface, the environment is the most Earth-like in the
Solar System
The Solar SystemCapitalization 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 S ...
beyond Earth itself – a pressure of approximately 1
atm or 1000
hPa HPA may refer to:
Organizations
* Harry Potter Alliance, a charity
* Halifax Port Authority, Canada
* Hamburg Port Authority, Germany
* Hawaii Preparatory Academy, a school in Hawaii, US
* Health Protection Agency, UK
* Heerespersonalamt, the Ger ...
and temperatures in the range. Protection against
cosmic radiation
Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
would be provided by the atmosphere above, with shielding mass equivalent to Earth's.
At the top of the clouds the wind speed on Venus reaches up to , circling the planet approximately every four Earth days, in a phenomenon known as "super-rotation". Compared to the Venusian
solar day
A synodic day (or synodic rotation period or solar day) is the period for a celestial object to rotate once in relation to the star it is orbiting, and is the basis of solar time.
The synodic day is distinguished from the sidereal day, which is ...
of 118 Earth days, colonies freely floating in this region could therefore have a much shorter day-night cycle. Allowing a colony to move freely would also reduce structural stress from the wind that they would experience if tethered to the ground.
Advantages
Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates rather than an
explosive decompression
Uncontrolled decompression is an unplanned drop in the pressure of a sealed system, such as an aircraft cabin or hyperbaric chamber, and typically results from human error, material fatigue, engineering failure, or impact, causing a pressure vesse ...
, giving time to repair any such damages.
In addition, humans would not require
pressurized suit
A pressure suit is a protective suit worn by high-altitude pilots who may fly at altitudes where the air pressure is too low for an unprotected person to survive, even breathing pure oxygen at positive pressure. Such suits may be either full-pr ...
s when outside, merely air to breathe, protection from the acidic rain and on some occasions low level protection against heat. Alternatively, two-part domes could contain a lifting gas like hydrogen or helium (extractable from the atmosphere) to allow a higher mass density.
Therefore, putting on or taking off suits for working outside would be easier. Working outside the vehicle in non-pressurized suits would also be easier.
Remaining problems
Structural and industrial materials would be hard to retrieve from the surface and expensive to bring from Earth/asteroids. The sulfuric acid itself poses a further challenge in that the colony would need to be constructed of or coated in materials resistant to corrosion by the acid, such as
PTFE
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...
(a compound consisting wholly of carbon and fluorine).
Studies
In 2015, NASA developed the
High Altitude Venus Operational Concept
High Altitude Venus Operational Concept (HAVOC) is a set of crewed NASA mission concepts to the planet Venus. All human portions of the missions would be conducted from lighter-than-air craft or from orbit.
Background
Venus is a planet with a ru ...
(HAVOC) for exploring the possibility of setting up an atmospheric crewed mission.
Terraforming
Venus has been the subject of a number of
terraforming
Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make ...
proposals.
[ Paper AIAA-2011-7215, AIAA Space 2011 Conference & Exposition, Long Beach CA, Sept. 26-29, 2011.] The proposals seek to remove or convert the dense carbon dioxide atmosphere, reduce Venus's surface temperature, and establish a day/night light cycle closer to that of Earth.
Many proposals involve deployment of a solar shade or a system of orbital mirrors, for the purpose of reducing
insolation and providing light to the dark side of Venus. Another common thread in most proposals involves some introduction of large quantities of
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-toxic, an ...
or
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 a ...
. Proposals also involve either freezing most of Venus's atmospheric CO
2, or converting it to
carbonates
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...
,
The Terraforming of Venus
/ref> urea
Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.
Urea serves an important r ...
or other forms.
See also
* Colonization of Mars
Colonization or settlement of Mars is the theoretical human migration and long-term human establishment of Mars. The prospect has garnered interest from public space agencies and private corporations and has been extensively explored in scien ...
* Colonization of the Moon
Colonization of the Moon or Lunar settlement is a process, or concept employed by some proposals, for claiming robotic or human exploitation and settlement on the Moon.
Laying claim to the Moon has been declared illegal through international ...
* Colonization of the Solar System
* Manned Venus flyby
* Observations and explorations of Venus
Observations of the planet Venus include those in antiquity, telescopic observations, and from visiting spacecraft. Spacecraft have performed various flybys, orbits, and landings on Venus, including balloon probes that floated in the atmospher ...
* Aerospace architecture
Aerospace architecture is broadly defined to encompass architectural design of non-habitable and habitable structures and living and working environments in aerospace-related facilities, habitats, and vehicles. These environments include, but are n ...
References
External links
A Floating City on Venus
– article fro
The Space Monitor
NASA's Incredible, Futuristic, And Totally Real Plan To Establish A Human Colony On Venus
– article fro
Business Insider UK
{{Space colonization
Colonization
Colonization, or colonisation, constitutes large-scale population movements wherein migrants maintain strong links with their, or their ancestors', former country – by such links, gain advantage over other inhabitants of the territory. When ...
Colonization
Colonization, or colonisation, constitutes large-scale population movements wherein migrants maintain strong links with their, or their ancestors', former country – by such links, gain advantage over other inhabitants of the territory. When ...
*Venus