Mars.

Many people believe that space colonization is a desirable and perhaps inevitable step in the future of humanity. Mars is the focus of much speculation and serious study about possible colonies. Mars is the easiest planet to reach from Earth in terms of energy (delta V) requirements. Still, a trip to Mars requires several months in space. Download high resolution version (1023x1023, 585 KB) File links The following pages link to this file: Mars Valles Marineris Wikipedia:Featured pictures visible Wikipedia talk:Selected anniversaries Wikipedia:Selected anniversaries/August Wikipedia:Selected anniversaries/August 27 Wikipedia:Selected anniversaries/All Template:Pic of the day/Archive1 Template:Pic of the... Download high resolution version (1023x1023, 585 KB) File links The following pages link to this file: Mars Valles Marineris Wikipedia:Featured pictures visible Wikipedia talk:Selected anniversaries Wikipedia:Selected anniversaries/August Wikipedia:Selected anniversaries/August 27 Wikipedia:Selected anniversaries/All Template:Pic of the day/Archive1 Template:Pic of the... Artists conception of a space habitat called the Stanford torus, by Don Davis Space colonization, also called space settlement and space humanization, is the hypothetical permanent autonomous (self-sufficient) human habitation of locations outside Earth. ... Mars, with polar ice caps visible. ... In general physics, delta-v is simply the change in velocity. ...

Similarity to Earth

While Earth is most like neighbour Venus in bulk composition, Mars' similarities to Earth are ultimately more compelling when considering colonization. Similarities include: Genitive Venusian or Venetian (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Mars, with polar ice caps visible. ... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third-closest planet to the Sun. ...

• the Martian day (or sol) is very close to Earth's. A Mars solar day is 24 hours 39 minutes 35.244 seconds[1]. See timekeeping on Mars .
• Mars has a surface area that is 28.4% of Earth's, only slightly less than the amount of dry land on Earth (which is 29.2% of Earth's surface).
• Mars has an axial tilt of 25.19°, compared with Earth's 23.44°. As a result, Mars has seasons much like Earth, though they last nearly twice as long because the Martian year is about 1.88 Earth years.
• Mars has an atmosphere. While thin (about 0.7% of Earth's atmosphere), it provides some protection from solar and cosmic radiation and has been used successfully for aerobraking of spacecraft.
• Recent observations by NASAs Mars Exploration Rovers and ESA's Mars Express confirm the presence of water on Mars. Mars appears to have significant quantities all the elements necessary to support life.

Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... Various schemes have been used or proposed to keep track of time and date on the planet Mars independently of Earth time and calendars. ... Axial tilt is an astronomical term regarding the inclination angle of a planets rotational axis in relation to its orbital plane. ... (This template has been listed for deletion) A season is one of the major divisions of the year, generally based on cyclic changes of climate. ... Layers of Atmosphere (NOAA) Earths atmosphere is the layer of gases surrounding the planet Earth and retained by the Earths gravity. ... Solar irradiance spectrum at top of atmosphere. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... Categories: Spacecraft propulsion | Stub ... NASA Logo The National Aeronautics and Space Administration (NASA), which was established in 1958, is the agency responsible for the public space program of the United States of America. ... Artists Concept of Rover on Mars (credit: Maas Digital LLC) NASAs Mars Exploration Rover (MER) Mission (since 2003) is a unmanned Mars exploration mission that includes sending two Rovers (robots) to explore the Martian surface and geology. ... This article is about the European Space Agency. ... Concept model of the Mars Express spacecraft Mars Express is a Mars exploration mission of the European Space Agency and Italian Space Agency. ... Water (from the Old English word wæter; c. ... The term element can refer to: Chemical element — material that consists of atoms with the same number of protons in the nucleus (see also Periodic table). ...

Differences

There are differences, of course, between Earth and Mars:

• The surface gravity on Mars is only 1/3 that of Earth. It is not known if this level is high enough to prevent the health problems associated with weightlessness.
• Mars is much colder than Earth, with a mean surface temperature of -63° Celsius and a low of -140° C.
• There are no standing bodies of liquid water on the surface of Mars.
• Because Mars is further from the Sun, the level of solar energy reaching the surface (the solar constant) is only about half that at the Earth and the Moon.
• Mars' orbit is more eccentric than Earth's, exacerbating temperature and solar constant variations.
• The atmospheric pressure on Mars is too low for humans to survive long without pressure suits.
• The Martian atmosphere consists mainly of carbon dioxide. However the partial pressure of CO₂ at the surface of Mars is some 52 times higher than on Earth, possibly allowing Mars to support plant life.
• Mars has two moons and they are much smaller and closer to the planet than Earth's Moon. Phobos and Deimos might prove useful as places to test concepts for colonizing the asteroids.

The surface gravity of a Killing horizon is the acceleration, as exerted at infinity, needed to keep an object at the horizon. ... Astronauts on the International Space Station display an example of weightlessness Weightlessness is the experience (by people and objects) during freefall, of having no apparent weight. ... The degree Celsius (°C or ℃ (Unicode 0x2103)) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ... By ancient tradition, the Sun is the light in the heavens whose presence is day and whose absence is night. ... The solar constant is the amount of incoming solar radiation per unit area, measured on the outer surface of Earths atmosphere, in a plane perpendicular to the rays. ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... Approximately, the partial pressure of a gas in atmospheres in a mixture or solution is what would be the pressure of that gas if all other components of the mixture or solution suddenly vanished without its temperature changing. ... Phobos (IPA , Greek Φόβος: Fright), is the larger and innermost of Mars two moons, named after Phobos, son of Ares (Mars) from Greek Mythology. ... Deimos (IPA or ; Greek Δείμος: Dread), is the smaller and outermost of Mars two moons, named after Deimos from Greek Mythology. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ...

Habitability

A human being would not survive more than a minute or so on the surface of Mars without protective equipment. However conditions on Mars are much closer to habitability than the furnace-hot temperatures on Mercury and Venus, the cryogenic cold of the outer planets or the hard vacuum of the Moon and asteroids. There are natural settings on Earth where humans have explored that match most conditions on Mars. The highest altitude reached by a manned balloon ascent, a record set in May, 1961, was 34,668 meters (113,740 feet) The pressure at that altitude is about the same as on the surface of Mars. Extreme cold in the Arctic and Antarctic match all but the most extreme temperatures on Mars. Also, there are deserts on Earth that look similar to Martian terrain. For additional meanings, see Mercury (disambiguation). ... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Cryogenics is the study of very low temperatures or the production of the same, and is often confused with cryobiology, the study of the effect of low temperatures on organisms, or the study of cryopreservation. ... The outer planets are those planets that have been discovered in the modern era. ... This article is about absence of matter. ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... High altitude balloons are balloons, usually filled with helium, that are released into the upper atmosphere, generally reaching between 60,000 and 120,000 feet. ... Greek ἀνταρκτικός, opposite the arctic) is a continent surrounding the Earths South Pole. ... A dune in the Egyptian desert Desert in California In geography, a desert is a landscape form or region that receives little precipitation, less than 200 mm per year. ...

Radiation

Mars has no global geomagnetic field comparable to Earth's. Combined with a thin atmosphere, this increases the amount of ionizing radiation that reaches the Martian surface. The Mars Odyssey spacecraft carried an instrument, the Mars Radiation Environment Experiment (MARIE), to measure the dangers to humans. MARIE found that radiation levels in orbit above Mars are 2.5 times higher than at the International Space Station. Average doses were about 22 millirad per day (220 microgray/day or 0.8 gray/year). A three year exposure to such levels would be close to the safety limits currently adopted by NASA. Levels at the Martian surface would be somewhat lower and might vary significantly at different locations depending on altitude and local magnetic fields. Living quarters and work spaces could be shielded using Martian dirt, greatly reducing exposure during times humans were indoors. The cause of Earths magnetic field (the surface magnetic field) is not known for certain, but is possibly explained by dynamo theory. ... Ionizing radiation is a type of particle radiation in which an individual particle (for example, a photon, electron, or helium nucleus) carries enough energy to ionize an atom or molecule (that is, to completely remove an electron from its orbit). ... Artists concept of the 2001 Mars Odyssey Spacecraft 2001 Mars Odyssey is an unmanned spacecraft orbiting the planet Mars. ... MARIE, designed to measure radiation, started malfunctioning shortly after a series of strong solar flares occurred in Fall of 2003 The Martian Radiation Experiment, or MARIE was designed to measure the radiation environment of Mars using an energetic particle spectrometer. ... ISS Statistics Crew: 2 As of August 21, 2005 Perigee: 352. ... The rad is a unit of radiation dose, with symbol rad. ... A gray, (symbol: Gy), is the SI unit for the absorbed dose of radiation. ...

Occasional solar proton events (SPEs) produce much higher doses. Astronauts on Mars could be warned of SPEs by sensors closer to the Sun and take shelter during these events. Some SPEs were observed by MARIE that were not seen by sensors near Earth, apparently because SPEs are directional. This would imply that a network of spacecraft in orbit around the Sun would be needed to insure all SPEs threatening Mars were detected. A Solar Proton Event occurs when high-energy protons, ejected from the suns surface during a solar flare, get caught by the Earths magnetic field and cause ionization in the ionosphere. ...

Much remains to be learned about space radiation. In 2003, NASA's Lyndon B. Johnson Space Center opened a facility, the NASA Space Radiation Laboratory, at Brookhaven National Laboratory that employs particle accelerators to simulate space radiation. The facility will study its effects on living organisms along with shielding techniques. An aerial view of the complete Johnson Space Center facility in Houston, Texas in 1989. ... Aerial view of Brookhaven National Laboratory. ... One of the early particle accelerators responsible for development of the atomic bomb. ...

Communication

Communications with Earth are relatively straightforward during the half-sol when the Earth is above the Martian horizon. NASA included communications relay equipment in several of its Mars orbiters, so Mars already has communications satellites. However, they will likely have worn out and need to be replaced before colonization expeditions are mounted. NASA plans to launch a Mars Telecommunications Orbiter in 2009. U.S. military MILSTAR communications satellite A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications. ...

Communication can be difficult for a few days every synodic period, around the time of superior conjunction when the Sun is directly between Mars and Earth. The round trip communication delay due to the speed of light ranges from about 6.5 minutes at closest approach to 44 minutes at superior conjunction. Ordinary voice conversation with Earth may never be possible, but e-mail and voice mail pose little difficulty. The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Conjunction is a term used in positional astronomy and astrology. ... By ancient tradition, the Sun is the light in the heavens whose presence is day and whose absence is night. ... Cherenkov effect in a swimming pool nuclear reactor. ... Wikipedia does not yet have an article with this exact name. ... Voicemail (or voice mail; abbreviated v-mail or vmail) is a specific application of an interactive voice response system. ...

Ordinary two-way radios will work well over line of sight distances. Mars has an ionosphere. It is not clear to what extent it could be used to reflect long distance high frequency communications between points far apart on the Martian surface. When viewing a scene, as in optics, photography, or even hunting, the line of sight is the straight line between the observer and the target. ... The ionosphere is the part of the [[Earths htyjsrtjaryjarykj The lowest part of the Earths atmosphere is called the troposphere and it extends from the surface up to about 10 km (6 miles). ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ...

Possible locations for colonies

Mars can be broken into broad regions for discussion of possible colony sites.

Polar regions

Mars' north and south poles once attracted great interest as colony sites because seasonally-varying polar ice caps have long been observed by telescope from Earth. Mars Odyssey found the largest concentration of water near the north pole, but also showed that water likely exists in lower lattitudes as well, making the poles less compelling as a colony locale. Like Earth, Mars sees a midnight sun at the poles during local summer and polar night during local winter. Latitude, denoted by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... The midnight sun at Nordkapp, Norway The midnight sun is a phenomenon occurring in latitudes north of the arctic circle and south of the antarctic circle where the sun is continuously visible for at least 24 hours. ... The polar night is the night lasting more than 24 hours, usually inside the polar circles. ...

Midlands

Download high resolution version (1614x779, 326 KB) Mars Exploration Rover Opportunity looks back at its landing site and protective pod in a small crater in Meridiani Planum. ...

The exploration of Mars' surface is still underway. The two Mars Exploration Rovers, Spirit and Opportunity, have encountered very different soil and rock characteristics. This suggests that the Martian landscape is quite varied and the ideal location for a colony is best determined after more data becomes available. As on Earth, the further one goes from the equator, the greater the seasonal climate variation one encounters. Artists Concept of Rover on Mars (credit: Maas Digital LLC) NASAs Mars Exploration Rover (MER) Mission (since 2003) is a unmanned Mars exploration mission that includes sending two Rovers (robots) to explore the Martian surface and geology. ...

Valles Marineris

Download high resolution version (968x344, 64 KB)Valles Marineris; http://photojournal. ...

Valles Marineris, the "Grand Canyon" of Mars, is over over 3,000 km long and averages 8 km deep. Atmospheric pressure at the bottom would be some 25% higher than the surface average, 0.9 kPa vs 0.7 kPa. The canyon runs roughly east-west, so shadows from its walls should not interfere too badly with solar power collection. Ancient river channels lead from the canyon, indicating it was once flooded. The exposed walls of the canyon could offer a window into Martian geologic history, much as the walls of Earth's Grand Canyon provide. Valles Marineris cuts a wide swath across the face of Mars Valles Marineris (Latin for Mariner Valley, named after the Mariner 9 Mars orbiter of 1971-72 which discovered it. ... Grand Cañon at the foot of the Toroweap - looking east, by William Henry Holmes The Grand Canyon is a colorful, steep-sided gorge, carved by the Colorado River, in northern Arizona. ... Wikipedia does not yet have an article with this exact name. ...

Concerns

Besides the general criticism of human colonization of space (see space colonization for a discussion), there are specific concerns about a colony on Mars: Artists conception of a space habitat called the Stanford torus, by Don Davis Space colonization, also called space settlement and space humanization, is the hypothetical permanent autonomous (self-sufficient) human habitation of locations outside Earth. ...

• some worry about contamination of the planet with Earth life. The question of whether life once existed or exists now on Mars has not been settled. See Life on Mars.
• many believe Mars might be more economically explored by robots, though arguably that could precede any colonization activity.
• others suggest the Moon as a more logical first location for a planetary colony, perhaps using it as a staging area for future manned missions to Mars, despite the fact that the Moon is completely lacking in several of the key elements required for life, most notably hydrogen, nitrogen and carbon.

Scientists have long speculated about the possibility of life on Mars, due to that planets proximity and similarity to Earth. ... A humanoid robot playing the trumpet In practical usage, a robot is a mechanical device which performs automated physical tasks, either according to direct human supervision, a pre-defined program, or a set of general guidelines using artificial intelligence techniques. ...

See also

• Colonization of the Moon
• Colonization of the outer solar system
• Exploration of Mars
• Mars Analogue Research Station Programme
• Mars in fiction
• Mars Society
• NASA's Vision for Space Exploration
• Solar system
• Terraforming
• The Case for Mars

An artists rendering of a lunar base. ... Some of the moons of the outer planets of the solar system are large enough to be suitable places for colonization. ... Computer generated image of one of the two Mars Exploration Rovers which touched down on Mars in 2004. ... FMARS, Devon Island (credit: The Mars Society UK) // Overview The Mars Analogue Research Station (MARS) Programme is an international effort spearheaded by The Mars Society to establish a network of prototype research centres where scientists and engineers can live and work as if they were on Mars, to develop the... The dramatic red color and rapid apparent motion of the planet Mars as seen in the sky of Earth has always made it an object of interest, and this was only increased by early scientific speculations that its surface conditions might be capable of supporting life. ... The Mars Society is a space advocacy non-profit organization dedicated to encouraging the exploration and settlement of Mars. ... NASA Logo The National Aeronautics and Space Administration (NASA), which was established in 1958, is the agency responsible for the public space program of the United States of America. ... Image from NASA site The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... Presentation of the solar system (not to scale) The solar system consists of the Sun and all the objects that orbit around it, including meteoroids, planetoids, comets, moons, and planets. ... Artists conception of a terraformed Mars in three stages of development. ... The Case For Mars: The Plan to Settle the Red Planet and Why We Must is a nonfiction science book by Robert Zubrin, first published in 1996. ...

External links

• The Planetary Society
• Red Colony web site
• The Case for Mars