When Will Humans Live on Mars?/ video
When Will Humans Live on Mars?/ video In the picture is an artist's conception of a human Mars base, with a cutaway revealing an interior horticultural area. Earth is the only home we've ever known, and it's treated us well so far. But whether it's climate change, an apocalyptic asteroid, or some horrifying disaster we don't even know about yet, the Earth won't live forever.
Luckily for us, we are in the middle of a new space race, one fueled not by countries trying to plant a flag on the Moon, but by explorers looking to get rich on Mars and beyond. The hope of these entrepreneurs is that in their quest for dollars, we'll find a way to help humanity settle on new worlds. Mars is the focus of much speculation and serious study about possible human colonization. Its surface conditions and the likely availability of water make it arguably the most hospitable of the planets, other than Earth. Mars requires less energy per unit mass (delta V) to reach from Earth than any planet except Venus. However, at minimum energy use, a trip to Mars requires 6–7 months in space using current chemical propulsion methods. he Martian day (or sol) is very close in duration to Earth's. A solar day on Mars is 24 hours 39 minutes 35.244 seconds.
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 half the radius of Earth and only one-tenth the mass. This means that it has a smaller volume (~15%) and lower average density than Earth.
Mars has an axial tilt of 25.19°, similar to 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. The Martian north pole currently points at Cygnus, not Ursa Minor like Earth's.
Recent observations by NASA's Mars Reconnaissance Orbiter, ESA's Mars Express and NASA's Phoenix Lander confirm the presence of water ice on Mars. While there are some extremophile organisms that survive in hostile conditions on Earth, including simulations that approximate Mars, plants and animals generally cannot survive the ambient conditions present on the surface of Mars.
The surface gravity of Mars is 38% that of Earth. Although microgravity is known to cause health problems such as muscle loss and bone demineralization, it is not known if Martian gravity would have a similar effect. The Mars Gravity Biosatellite was a proposed project designed to learn more about what effect Mars's lower surface gravity would have on humans.
Mars is much colder than Earth, with a mean surface temperature between 186 and 268 K (−87 °C, -124.6 °F and −5 °C, 23 °F). The lowest temperature ever recorded on Earth was 180 K (−93.2 °C, -135.76 °F) in Antarctica.
Surface water on Mars may occur transiently, but only under certain conditions.
Because Mars is approximately 52% further from the Sun, the amount of solar energy entering the upper atmosphere per unit area (the solar constant) is only around 43.3% of what reaches the Earth's upper atmosphere. However, due to the much thinner atmosphere, more solar energy reaches the surface.
Mars's orbit is more eccentric than Earth's, increasing temperature and solar constant variations.
Due to the relative lack of a magnetosphere, in combination with a thin atmosphere—less than 1% that of Earth's—Mars has extreme amounts of ultraviolet radiation that would pose an ongoing and serious threat.
The atmospheric pressure on Mars is far below the Armstrong limit at which people can survive without pressure suits. Since terraforming cannot be expected as a near-term solution, habitable structures on Mars would need to be constructed with pressure vessels similar to spacecraft, capable of containing a pressure between 30 and 100 kPa. See Atmosphere of Mars.
The Martian atmosphere is 95% carbon dioxide, 3% nitrogen, 1.6% argon, and traces of other gases including oxygen totaling less than 0.4%.
Martian air has a partial pressure of CO2 of 0.71 kPa, compared to 0.031 kPa on Earth. CO2 poisoning (hypercapnia) in humans begins at about 0.10 kPa. Even for plants, CO2 much above 0.15 kPa is toxic. This means Martian air is completely toxic to both plants and animals even at the reduced total pressure.
Conditions on the surface of Mars are closer to the conditions on Earth in terms of temperature, atmospheric pressure than on any other planet or moon, except for the cloud tops of Venus, but are not hospitable to humans or most known life forms due to greatly reduced air pressure, an atmosphere with only 0.1% oxygen, and the lack of liquid water (although large amounts of frozen water have been detected).
In 2012, it was reported that some lichen and cyanobacteria survived and showed remarkable adaptation capacity for photosynthesis after 34 days in simulated Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR).
Humans have explored parts of Earth that match some conditions on Mars. Based on NASA rover data, temperatures on Mars (at low latitudes) are similar to those in Antarctica. The atmospheric pressure at the highest altitudes reached by manned balloon ascents (35 km (114,000 feet) in 1961, 38 km in 2012) is similar to that on the surface of Mars.
Human survival on Mars would require complex life support measures and living in artificial environments.
Terraforming of Mars:
There is much discussion regarding the possibility of terraforming Mars to allow a wide variety of life forms, including humans, to survive unaided on Mars's surface, including the technologies needed to do so.
Mars has no global magnetic field comparable to Earth's geomagnetic field. Combined with a thin atmosphere, this permits a significant amount of ionizing radiation to reach 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 millirads per day (220 micrograys per day or 0.08 grays per 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. Building living quarters underground (possibly in lava tubes that are already present) would significantly lower the colonists' exposure to radiation. Occasional solar proton events (SPEs) produce much higher doses.
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 studies its effects on living organisms along with shielding techniques. Initially, there was some evidence that this kind of low level, chronic radiation is not quite as dangerous as once thought; and that radiation hormesis occurs. However, results from a 2006 study indicated that protons from cosmic radiation may cause twice as much serious damage to DNA as previously expected, exposing astronauts to greater risk of cancer and other diseases. As a result of the higher radiation in the Martian environment, the summary report of the Review of U.S. Human Space Flight Plans Committee released in 2009 reported that "Mars is not an easy place to visit with existing technology and without a substantial investment of resources." NASA is exploring a variety of alternative techniques and technologies such as deflector shields of plasma to protect astronauts and spacecraft from radiation.
Equipment needed for colonization:
Colonization of Mars will require a wide variety of equipment—both equipment to directly provide services to humans and production equipment used to produce food, propellant, water, energy and breathable oxygen—in order to support human colonization efforts. Required equipment will include:
resource extraction equipment—initially for water and oxygen, later for a wider cross section of minerals, building materials, etc.
energy production and storage equipment, some solar and perhaps other forms as well
food production spaces and equipment
propellant production equipment, generally thought to be hydrogen and methane for fuel—with oxygen oxidizer—for chemical rocket engines
fuels or other energy source for use with surface transportation. Carbon monoxide/oxygen (CO/O2) engines have been suggested for early surface transportation use as both carbon monoxide and oxygen can be straightforwardly produced by zirconia electrolysis from the Martian atmosphere without requiring use of any of the Martian water resources to obtain hydrogen.
Communications with Earth are relatively straightforward during the half-sol when Earth is above the Martian horizon. NASA and ESA included communications relay equipment in several of the Mars orbiters, so Mars already has communications satellites. While these will eventually wear out, additional orbiters with communication relay capability are likely to be launched before any colonization expeditions are mounted.
The one-way communication delay due to the speed of light ranges from about 3 minutes at closest approach (approximated by perihelion of Mars minus aphelion of Earth) to 22 minutes at the largest possible superior conjunction (approximated by aphelion of Mars plus aphelion of Earth). Real-time communication, such as telephone conversations or Internet Relay Chat, between Earth and Mars would be highly impractical due to the long time lags involved. NASA has found that direct communication can be blocked for about two weeks every synodic period, around the time of superior conjunction when the Sun is directly between Mars and Earth, although the actual duration of the communications blackout varies from mission to mission depending on various factors—such as the amount of link margin designed into the communications system, and the minimum data rate that is acceptable from a mission standpoint. In reality most missions at Mars have had communications blackout periods of the order of a month.
A satellite at the L4 or L5 Earth–Sun Lagrangian point could serve as a relay during this period to solve the problem; even a constellation of communications satellites would be a minor expense in the context of a full colonization program. However, the size and power of the equipment needed for these distances make the L4 and L5 locations unrealistic for relay stations, and the inherent stability of these regions, although beneficial in terms of station-keeping, also attracts dust and asteroids, which could pose a risk. Despite that concern, the STEREO probes passed through the L4 and L5 regions without damage in late 2009.
Recent work by the University of Strathclyde's Advanced Space Concepts Laboratory, in collaboration with the European Space Agency, has suggested an alternative relay architecture based on highly non-Keplerian orbits. These are a special kind of orbit produced when continuous low-thrust propulsion, such as that produced from an ion engine or solar sail, modifies the natural trajectory of a spacecraft. Such an orbit would enable continuous communications during solar conjunction by allowing a relay spacecraft to "hover" above Mars, out of the orbital plane of the two planets. Such a relay avoids the problems of satellites stationed at either L4 or L5 by being significantly closer to the surface of Mars while still maintaining continuous communication between the two planets.
The path to a human colony could be prepared by robotic systems such as the Mars Exploration Rovers Spirit, Opportunity and Curiosity. These systems could help locate resources, such as ground water or ice, that would help a colony grow and thrive. The lifetimes of these systems would be measured in years and even decades, and as recent developments in commercial spaceflight have shown, it may be that these systems will involve private as well as government ownership. These robotic systems also have a reduced cost compared with early crewed operations, and have less political risk.
Wired systems might lay the groundwork for early crewed landings and bases, by producing various consumables including fuel, oxidizers, water, and construction materials. Establishing power, communications, shelter, heating, and manufacturing basics can begin with robotic systems, if only as a prelude to crewed operations.
Mars Surveyor 2001 Lander MIP (Mars ISPP Precursor) was to demonstrate manufacture of oxygen from the atmosphere of Mars, and test solar cell technologies and methods of mitigating the effect of Martian dust on the power systems.
Before any people are transported to Mars on the notional 2030s Mars Colonial Transporter envisioned by SpaceX, a number of robotic cargo missions would be undertaken first in order to transport the requisite equipment, habitats and supplies. Equipment that would be necessary would include "machines to produce fertilizer, methane and oxygen from Mars' atmospheric nitrogen and carbon dioxide and the planet's subsurface water ice" as well as construction materials to build transparent domes for initial agricultural areas. - http://www.forbiddenknowledgetv.com/videos/space/when-will-humans-live-o...
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