Category Archives: Mars Colonization

The arrival of ChatGPT has placed artificial intelligence at the center of US discourse. Not surprisingly, one touchstone for these debates have been the novels of sci-fi author Philip K. Dick. As it happens, this AI-inspired interest in the author of Do Androids Dream of Electric Sheep?, among many other visionary works, comes at a time when American policy elites are also gripped by a new urban malaiseanother constant motif in Dicks body of work.

Today, this pair of Dickian concernsthe rise of the AI era and urban declineare assigned different weights by the left and the right. So far, its mostly progressive institutions like The New York Times sounding the alarm about the risks of unhindered AI. The mostly libertarian-inflected right, by contrast, has taken a predictable Let it rip! attitude, the better to punish coastal liberals whose bullshit jobs are threatened by platforms like ChatGPT.

Meanwhile, Americas urban malaise codes as a right-wing concern, with conservative politicians and media determined to make electoral hay of disorder in the cities, a situation that they charge has been exacerbated by liberal politicos lax approach to lifestyle crimes. Among conservatives, the term blue city is permanently (and not wholly unjustly) linked with needle-strewn sidewalks, homeless encampments, and rampant shoplifting.

The two issues are, in fact, closely entangled, in a way that Dick saw clearly but that has often eluded both his cinematic interpreters and the elites who have sought to understand the present by examining his imagined futures. A minor episode in the intellectual history of Los Angeles illustrates this. That was the last time American officialdom turned to Dick as a prophet, albeit via Blade Runner, Ridley Scotts cinematic adaptation of Do Androids?

In 1988, some 150 eminent citizens of LAleaders in politics, business, academe, and philanthropysubmitted a report to then-Mayor Tom Bradley outlining their ambitions for the city as it prepared for the 21st century. In the most notable contribution, the California historian Kevin Starr paid tribute to generations of Angelinos for embracing a headlong futurity: constantly adapting the environment to their visions, natural limits be damned.

Yet Starr wasnt without his fears. The LA of the 1920san era of dramatic growth, when the city had willed its water, railroads, and housing stock into being and then invited a million newcomershad a dominant establishment and a dominant population. He meant white protestants. Yes, their primacy meant overlooking certain suppressions and injustices, but the old regime had supplied the civic unity needed to sustain cohesion amid explosive growth.

Where, Starr wondered, will Los Angeles 2000 find its community, its city in common? One answer came courtesy of Dick-inspired sci-fi: There is the Blade Runner scenario: the fusion of individual cultures into a demotic polyglotism ominous with unresolved hostilities that would now erupt in violence, now settle down in negotiated truce.

Techno-capitalism and urban dilapidation seemed to go hand-in-hand.

As the Marxist geographer Mike Davis, who died last year at age 76, noted, Starrs offhand remark attested to Blade Runners enduring status as the star of sci-fi dystopias. The film has become a sort of visual shorthand for a set of persistent American anxieties about biotechnology, corporate misrule, and multiculturalism, projected from the California dream factory onto the rest of the country (and the world). For Davis, it was significant that the dream factory, Hollywood, was located nearby other key Golden State industries, not least computing and biotech, whose business was to slingshot our species into Dickian dystopia.

Yet Davis wasnt very impressed by Blade Runner as a piece of urban futurism. While boasting whiz-bang effects (by 80s standards), the movie presented a retread of a much older old, and racially tinged, picture of the future as Manhattan-style giganticism: teeming masses of culturally mixed and confused human drones huddling under massive pyramids of steel and glass.

That picture no doubt appealed to the likes of Starr as they sought to place the sole blame for the political-economic dislocations and contradictions of California at the feet of multiculturalism. Lamenting the loss of WASP primacy was a lot easier than facing up to the de-industrialization and middle-class destruction wrought by the neoliberal revolution launched by the likes of Ronald Reagan and Margaret Thatcher.

For Davis, the Kevin Starr/Blade Runner vision of Los Angeles (as yellow-peril giganticism) missed something still more crucial: the fact that the advances in technology hatched in California sat next to a great unbroken chain of aging bungalows, stucco apartments, and ranch style homesall decaying as the city entered the third millennium. Techno-capitalism and urban dilapidation, sentient machines and lousy bus lines, seemed to go hand-in-hand.

This overlapping of high-tech and physical disrepair is by now ubiquitous not just in California, but across the United States. In Gotham, where I live, Wall Streets Masters of the Universe are still at it, deploying unbelievably complex algorithms to squeeze arbitrage out of the real economy and into their own asset ledgers. Meanwhile, the roads connecting New York City to its airports are riddled with cracks and potholes that recall the Third World (except, many developing nations are actually pulling ahead and frequently boast gleaming new infrastructure). The city itself is filthier than I remember in more than a decade. The subway system dates from the 19th century. The mayor has appointed a rat czar.

America is still the worlds largest and, by some measures, most advanced economy. Yet its headlong futurity coexists with a country where bedbugs quite literally suck the life out of prisoners. New York, LA, Chicago, Seattle, and the Bay Area distill this apparent contradiction in especially concentrated form, but its a national problem. Indeed, Americas Republican-governed states are in some ways worse, since their low-tax, low-spending model fails to attract the sexy futuristic industries.

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Do Androids Dream of Terrible Streets? | Compact Mag - Compact Mag

Mars colonization projects have been imagined since a long time

Early in the history of spaceflight, Mars was the center of attention. As early as 1948 Wernher von Braun, one of the pioneers of modern astronautics, is thinking about a program of missions to the Red Planet. Even before the first space flight, his book Das MarsProjekt plans to send a team of 70 scientists in a fleet of ten spacecrafts. He calculates the possible trajectories and the different launch of the engines which would be necessary for this travel, according to the expeditions of Antarctic exploration of the time.

Such a mission to Mars seems almost grotesque today because obviously Wernher von Braun could not anticipate that the huge progress of robotics would allow us to explore Mars at a lower cost. Today, we know much more about Mars, but the ambitious missions imagined by the German engineer have never seen the light of day. Yet the idea comes back regularly lately. SpaceX, a private company, plans to make possible the Martian colonization. The manned trip to Mars is a very complex one. Even NASA does not seem to believe it. If humanity decides one day to leave permanently his cradle, does Mars necessarily represent the best of the destinations ?

Suppose SpaceX succeeds in sending dozens of men to Mars in the not-too-distant future. The very first issue of Martian colonization is transportation. The US companys solution is based on very large reusable spaceships, the BFRs, which would make the trip to the red planet in large number at each firing window, approximately every two years. These spaceships would work without the need for technological breakthroughs : the BFR is a reusable rocket with chemical propulsion, which is a little closer to the vision of Wernher von Braun.

SpaceXs mission program makes some choices to make the journey possible, including local fuel production. This detail makes the SpaceX project very different from what the Apollo missions or most Martian exploration projects may have been. The Martian colonization is not only an option allowed by the trip, it becomes necessary to it. Without the deployment of local production infrastructure, no return possible on Earth.

But there is a problem : if we go to Mars to establish a colony and establish a colony to make sure we can go back, what concrete benefits would there be for humanity to go to establish on another planet, and why Mars in particular ? Elon Musk, the founder of SpaceX, seems primarily concerned with safeguarding the human species, ensuring that humanity thrives on at least two planets. It is a kind of guarantee against the risk of extinction : if one of these two planets undergoes a major disaster, the other can survive. But an economic opportunity is needed for the colonization of Mars to be more than a fantasy.

On this side, if we look at the geography of the solar system, Mars may have arguments for a manufacturer of the future in search of valuable raw materials. The main asteroid belt is very interesting : it houses a lot of metals and precious materials easily accessible. Mars is exactly between the asteroid belt and the Earth. A little like the cities that developed along the railroad tracks, Mars could become a must step between Earth and their new El Dorado. Thanks to its low gravity, it could for example serve as a starting point for men or robots left to exploit the asteroid belt. These are obviously very long-term prospects.

If SpaceX manages to achieve its ambitions, its first passengers will have much more immediate concerns. Like all objects in the solar system outside the Earth, Mars is atrociously hostile to human life. Its average temperature hovers around -60 degrees Celsius and its low atmospheric pressure prohibits life outside a controlled environment. This atmosphere is so concentrated in CO2 that breathing it would poison a human, and even plants. Mars does not have a magnetosphere, so huge amounts of radiation fall on its surface. And we have absolutely no idea what its low gravity would cause in the long run on human organisms.

If you want to go to Mars, heres some good news : a Martian day lasts exactly 24 hours, 39 minutes and 35 seconds. Your sleep cycle should not be too disturbed. There is water on Mars, as well as all the chemical elements necessary for life. We can also think that Mars has welcomed life in the distant past. And a weak atmosphere and gravity stays better than no atmosphere and no gravity at all.

We still do not know much about SpaceXs colonization plans. The company is planning a first robotic flight in 2022 and a first manned flight in 2024, but the deadlines announced by Elon Musk are rarely respected. The goal of robotic flight is to ensure that local propellant production is possible. We should have an early response with NASAs March 2020 rover that embeds an experiment called the Mars Oxygen In-Situ Resource Utilization Experiment (Moxie). This experiment has to produce oxygen from the Martian atmosphere. SpaceX relies on the red planets water and carbon dioxide resources to produce oxygen and methane, thanks to a skilful mix of electrolysis and Sabatier reaction.

To make this possible, it takes a lot of energy, which is another problem. Mars is far enough from the sun to bring down the yields of solar panels. It is also regularly covered by huge dust storms that do not improve the situation. Ideally, nuclear energy would provide the best alternative, but SpaceXs preference for already proven solutions is well known. But to produce and store the thousands of tons of propellant needed for the return trip, it would be necessary to install a large number of solar panels. It is also necessary to feed the survival systems of the passengers of the mission. Whether the first Martian settlers come to Mars from a SpaceX spacecraft or from another company, local energy production is one of the biggest problems.

The environment of Mars is hostile but still offers some opportunities. For example, the problem of radiation could be solved quite simply by going under the surface of Mars. For that, there is no need for expensive drilling : the volcanism of the red planet has already done the work. It is believed that Mars hosts lava tubes, large underground and hollow corridors formed by lava flows due to the low gravity of the planet. These lava pipes could be much larger than those found on the Earth, which would allow to install vast habitats sheltered from radiation and micro-meteorites. The temperature would be easier to control.

For the purpose of colonization, the local production of a maximum of elements should be allowed : propellants, but also food for example, and why not building materials. Producing food on Mars is not easy : we need to fertilize the toxic soil of the planet and grow seeds and plants in a controlled atmosphere, and with a sufficient supply of light. Mars, however, could be a little more fertile than we think : an experiment conducted by the German Space Center found that lichen collected in Antarctica was able to survive in a Martian environment.

If Martian settlers manage to ensure their survival in a sustainable way, and even to take a certain independence from the Earth, they will then be able to set up a productive economy. But the initial investment to arrive at this result seems gigantic compared to the possible return on investment. Its a project that would take generations to become profitable, which is not the kind of perspective that private companies like.

One way to facilitate this could be to partially terra-shape the planet, ie not to make it completely identical to the Earth but to modify some of its specific parameters such as the absence of a magnetic field. In February 2017, Jim Green, scientist at NASA, devised a concept : a very powerful magnetic device installed at the L1 Lagrange point of the Sun-Mars system would include Mars in its magnetosphere. Thus protected from the solar wind, the atmosphere of Mars would thicken and its temperature would rise, perhaps even to make possible the liquid water on the surface.

What is certain is that the red planet will continue to make us dream for a long time. It is very difficult to predict what future humanity will grant to Mars : between private initiatives on the one hand and the changing plans of space agencies on the other, it seems impossible to know who will put the foot first on the red planet and especially when. What is certain is that the Martian colonization will represent a major turning point in the history of humanity.

Images by SpaceX Chesley Bonestell NASA / Clouds AO / SEArch [Public Domain], via Wikimedia Commons NASA Ames Research Center (Public domain), via Wikimedia Commons Daein Ballard [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

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All about Mars colonization and news 2023 - From Space With Love

We live in an era of renewed space exploration, where multiple agencies are planning to send astronauts to the Moon in the coming years. This will be followed in the next decade with crewed missions to Mars by NASA and China, who may be joined by other nations before long.

These and other missions that will take astronauts beyond Low Earth Orbit (LEO) and the Earth-Moon system require new technologies, ranging from life support and radiation shielding to power and propulsion.

And when it comes to the latter, Nuclear Thermal and Nuclear Electric Propulsion (NTP/NEP) is a top contender!

NASA and the Soviet space program spent decades researching nuclear propulsion during the Space Race.

A few years ago, NASA reignited its nuclear program for the purpose of developing bimodal nuclear propulsion a two-part system consisting of an NTP and NEP element that could enable transits to Mars in 100 days.

As part of the NASA Innovative Advanced Concepts (NIAC) program for 2023, NASA selected a nuclear concept for Phase I development. This new class of bimodal nuclear propulsion system uses a "wave rotor topping cycle" and could reduce transit times to Mars to just 45 days.

The proposal, titled "Bimodal NTP/NEP with a Wave Rotor Topping Cycle," was put forward by Prof. Ryan Gosse, the Hypersonics Program Area Lead at the University of Florida and a member of the Florida Applied Research in Engineering (FLARE) team.

Gosse's proposal is one of 14 selected by the NAIC this year for Phase I development, which includes a US$12,500 grant to assist in maturing the technology and methods involved. Other proposals included innovative sensors, instruments, manufacturing techniques, power systems, and more.

Nuclear propulsion essentially comes down to two concepts, both of which rely on technologies that have been thoroughly tested and validated.

For Nuclear-Thermal Propulsion (NTP), the cycle consists of a nuclear reactor heating liquid hydrogen (LH2) propellant, turning it into ionized hydrogen gas (plasma) that is then channeled through nozzles to generate thrust.

Several attempts have been made to build a test this propulsion system, including Project Rover, a collaborative effort between the US Air Force and the Atomic Energy Commission (AEC) that launched in 1955.

In 1959, NASA took over from the USAF, and the program entered a new phase dedicated to spaceflight applications. This eventually led to the Nuclear Engine for Rocket Vehicle Application (NERVA), a solid-core nuclear reactor that was successfully tested.

With the closing of the Apollo Era in 1973, the program's funding was drastically reduced, leading to its cancellation before any flight tests could be conducted. Meanwhile, the Soviets developed their own NTP concept (RD-0410) between 1965 and 1980 and conducted a single ground test before the program's cancellation.

Nuclear-Electric Propulsion (NEP), on the other hand, relies on a nuclear reactor to provide electricity to a Hall-Effect thruster (ion engine), which generates an electromagnetic field that ionizes and accelerates an inert gas (like xenon) to create thrust. Attempts to develop this technology include NASA's Nuclear Systems Initiative (NSI) Project Prometheus (2003 to 2005).

Both systems have considerable advantages over conventional chemical propulsion, including a higher specific impulse (Isp) rating, fuel efficiency, and virtually unlimited energy density.

While NEP concepts are distinguished for providing more than 10,000 seconds of Isp, meaning they can maintain thrust for close to three hours, the thrust level is quite low compared to conventional rockets and NTP.

The need for an electric power source, says Gosse, also raises the issue of heat rejection in space where thermal energy conversion is 30-40 percent under ideal circumstances.

And while NTP NERVA designs are the preferred method for crewed missions to Mars and beyond, this method also has issues providing adequate initial and final mass fractions for high delta-v missions.

This is why proposals that include both propulsion methods (bimodal) are favored, as they would combine the advantages of both. Gosse's proposal calls for a bimodal design based on a solid core NERVA reactor that would provide a specific impulse (Isp) of 900 seconds, twice the current performance of chemical rockets.

Gosse proposed cycle also includes a pressure wave supercharger or Wave Rotor (WR) a technology used in internal combustion engines that harnesses the pressure waves produced by reactions to compress intake air.

When paired with an NTP engine, the WR would use pressure created by the reactor's heating of the LH2 fuel to compress the reaction mass further. As Gosse promises, this will deliver thrust levels comparable to that of a NERVA-class NTP concept but with an Isp of 1400-2000 seconds. When paired with a NEP cycle, said Gosse, thrust levels are enhanced even further:

"Coupled with an NEP cycle, the duty cycle Isp can further be increased (1,800-4,000 seconds) with minimal addition of dry mass. This bimodal design enables the fast transit for manned missions (45 days to Mars) and revolutionizes the deep space exploration of our Solar System."

Based on conventional propulsion technology, a crewed mission to Mars could last up to three years. These missions would launch every 26 months when Earth and Mars are at their closest (aka. a Mars opposition) and would spend a minimum of six to nine months in transit.

A transit of 45 days (six and a half weeks) would reduce the overall mission time to months instead of years. This would significantly reduce the major risks associated with missions to Mars, including radiation exposure, the time spent in microgravity, and related health concerns.

In addition to propulsion, there are proposals for new reactor designs that would provide a steady power supply for long-duration surface missions where solar and wind power are not always available.

Examples include NASA's Kilopower Reactor Using Sterling Technology (KRUSTY) and the hybrid fission/fusion reactor selected for Phase I development by NASA's NAIC 2023 selection.

These and other nuclear applications could someday enable crewed missions to Mars and other locations in deep space, perhaps sooner than we think!

This article was originally published by Universe Today. Read the original article.

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New NASA Nuclear Rocket Plan Aims to Get to Mars in Just 45 Days

Comparison: Earth and MarsVideo (01:28) showing how three NASA orbiters mapped the gravity field of Mars

Mars is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land.[2] Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. The red-orange appearance of the Martian surface is caused by iron(III) oxide, or rust.[57] It can look like butterscotch;[58] other common surface colors include golden, brown, tan, and greenish, depending on the minerals present.[58]

Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials.[59][60] Current models of its interior imply a core consisting primarily of iron and nickel with about 1617% sulfur.[61] This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth's.[62] The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but it appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, magnesium, aluminium, calcium, and potassium. The average thickness of the planet's crust is about 50 kilometres (31mi), with a maximum thickness of 125 kilometres (78mi).[62] By comparison, Earth's crust averages 40 kilometres (25mi) in thickness.[63][64]

Mars is seismically active. InSight has detected and recorded over 450 marsquakes and related events in 2019.[65][66] In 2021 it was reported that based on eleven low-frequency Marsquakes detected by the InSight lander the core of Mars is indeed liquid and has a radius of about 183040km and a temperature around 19002000K. The Martian core radius is more than half the radius of Mars and about half the size of the Earth's core. This is somewhat larger than models predicted, suggesting that the core contains some amount of lighter elements like oxygen and hydrogen in addition to the ironnickel alloy and about 15% of sulfur.[67][68]

The core of Mars is overlaid by the rocky mantle, which, however, does not seem to have a thermally insulating layer analogous to the Earth's lower mantle.[68] The Martian mantle appears to be solid down to the depth of about 500km, where the low-velocity zone (partially melted asthenosphere) begins.[69] Below the asthenosphere the velocity of seismic waves starts to grow again and at the depth of about 1050km there lies the boundary of the transition zone extending down to the core.[68]

Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt,[71] although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth, or silica glass. Regions of low albedo suggest concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have been found.[72] Much of the surface is deeply covered by finely grained iron(III) oxide dust.[73]

Although Mars has no evidence of a structured global magnetic field,[74] observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternating bands found on Earth's ocean floors. One theory, published in 1999 and re-examined in October2005 (with the help of the Mars Global Surveyor), is that these bands suggest plate tectonic activity on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded.[75]

Scientists have theorized that during the Solar System's formation Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than Earth; these elements were probably pushed outward by the young Sun's energetic solar wind.[76]

After the formation of the planets, all were subjected to the so-called "Late Heavy Bombardment". About 60% of the surface of Mars shows a record of impacts from that era,[77][78][79] whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. There is evidence of an enormous impact basin in the Northern Hemisphere of Mars, spanning 10,600 by 8,500 kilometres (6,600 by 5,300mi), or roughly four times the size of the Moon's South Pole Aitken basin, the largest impact basin yet discovered.[80] This theory suggests that Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet.[81][82]

The geological history of Mars can be split into many periods, but the following are the three primary periods:[83][84]

Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200mya. Water flows in the grabens called the Cerberus Fossae occurred less than 20Mya, indicating equally recent volcanic intrusions.[86] The Mars Reconnaissance Orbiter has captured images of avalanches.[87][88]

The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth. They are necessary for growth of plants.[89] Experiments performed by the lander showed that the Martian soil has a basic pH of 7.7, and contains 0.6% of the salt perchlorate,[90][91] concentrations that are toxic to humans.[92][93]

Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted theories include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils.[94] Several other explanations have been put forward, including those that involve water or even the growth of organisms.[95][96]

Proportion of water ice present in the upper meter of the Martian surface for lower (top) and higher (bottom) latitudes

Water in its liquid form cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% that of Earth's,[22] except at the lowest elevations for short periods.[60][97] The two polar ice caps appear to be made largely of water.[24][25] The volume of water ice in the south polar ice cap, if melted, would be enough to cover the entire surface of the planet with a depth of 11 metres (36ft).[98] Large quantities of ice are thought to be trapped within the thick cryosphere of Mars. Radar data from Mars Express and the Mars Reconnaissance Orbiter (MRO) show large quantities of ice at both poles,[99][100] and at middle latitudes.[101] The Phoenix lander directly sampled water ice in shallow Martian soil on 31 July 2008.[102]

Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers, though some of these structures have been hypothesized to result from the action of glaciers or lava.[103][104] One of the larger examples, Ma'adim Vallis, is 700 kilometres (430mi) long, much greater than the Grand Canyon, with a width of 20 kilometres (12mi) and a depth of 2 kilometres (1.2mi) in places. It is thought to have been carved by flowing water early in Mars's history.[105] The youngest of these channels are thought to have formed only a few million years ago.[106] Elsewhere, particularly on the oldest areas of the Martian surface, finer-scale, dendritic networks of valleys are spread across significant proportions of the landscape. Features of these valleys and their distribution strongly imply that they were carved by runoff resulting from precipitation in early Mars history. Subsurface water flow and groundwater sapping may play important subsidiary roles in some networks, but precipitation was probably the root cause of the incision in almost all cases.[107]

Along crater and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and to face the Equator; all are poleward of 30 latitude. A number of authors have suggested that their formation process involves liquid water, probably from melting ice,[108][109] although others have argued for formation mechanisms involving carbon dioxide frost or the movement of dry dust.[110][111] No partially degraded gullies have formed by weathering and no superimposed impact craters have been observed, indicating that these are young features, possibly still active.[109] Other geological features, such as deltas and alluvial fans preserved in craters, are further evidence for warmer, wetter conditions at an interval or intervals in earlier Mars history.[112] Such conditions necessarily require the widespread presence of crater lakes across a large proportion of the surface, for which there is independent mineralogical, sedimentological and geomorphological evidence.[113] Further evidence that liquid water once existed on the surface of Mars comes from the detection of specific minerals such as hematite and goethite, both of which sometimes form in the presence of water.[114]

In 2004, Opportunity detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars.[115][116] The Spirit rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the presence of water, was found on the surface by NASA's Mars rover Opportunity.[117][118][119] It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within Martian minerals, is equal to or greater than that of Earth at 50300 parts per million of water, which is enough to cover the entire planet to a depth of 2001,000 metres (6603,280ft).[120][121]

On 18 March 2013, NASA reported evidence from instruments on the Curiosity rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock.[122][123] Analysis using the rover's DAN instrument provided evidence of subsurface water, amounting to as much as 4% water content, down to a depth of 60 centimetres (24in), during the rover's traverse from the Bradbury Landing site to the Yellowknife Bay area in the Glenelg terrain.[122] In September 2015, NASA announced that they had found strong evidence of hydrated brine flows in recurring slope lineae, based on spectrometer readings of the darkened areas of slopes.[124][125][126] These streaks flow downhill in Martian summer, when the temperature is above 23 Celsius, and freeze at lower temperatures.[127] These observations supported earlier hypotheses, based on timing of formation and their rate of growth, that these dark streaks resulted from water flowing just below the surface.[128] However, later work suggested that the lineae may be dry, granular flows instead, with at most a limited role for water in initiating the process.[129] A definitive conclusion about the presence, extent, and role of liquid water on the Martian surface remains elusive.[130][131]

Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial.[132] In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of water to deuterium in the modern Martian atmosphere compared to that ratio on Earth. The amount of Martian deuterium is eight times the amount that exists on Earth, suggesting that ancient Mars had significantly higher levels of water. Results from the Curiosity rover had previously found a high ratio of deuterium in Gale Crater, though not significantly high enough to suggest the former presence of an ocean. Other scientists caution that these results have not been confirmed, and point out that Martian climate models have not yet shown that the planet was warm enough in the past to support bodies of liquid water.[133] Near the northern polar cap is the 81.4 kilometres (50.6mi) wide Korolev Crater, which the Mars Express orbiter found to be filled with approximately 2,200 cubic kilometres (530cumi) of water ice.[134]

In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.[135][136] During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, probably subsurface ice, in the Valles Marineris canyon system.[137]

North polar early summer water ice cap (1999); a seasonal layer of carbon dioxide ice forms in winter and disappears in summer.

Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 2530% of the atmosphere into slabs of CO2 ice (dry ice).[139] When the poles are again exposed to sunlight, the frozen CO2 sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the Opportunity rover in 2004.[140]

The caps at both poles consist primarily (70%) of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick. This permanent dry ice cover at the south pole is peppered by flat floored, shallow, roughly circular pits, which repeat imaging shows are expanding by?? meters per year; this suggests that the permanent CO2 cover over the south pole water ice is degrading over time.[141] The northern polar cap has a diameter of about 1,000 kilometres (620mi),[142] and contains about 1.6million cubic kilometres (5.71016cuft) of ice, which, if spread evenly on the cap, would be 2 kilometres (1.2mi) thick.[143] (This compares to a volume of 2.85million cubic kilometres (1.011017cuft) for the Greenland ice sheet.) The southern polar cap has a diameter of 350 kilometres (220mi) and a thickness of 3 kilometres (1.9mi).[144] The total volume of ice in the south polar cap plus the adjacent layered deposits has been estimated at 1.6million cubic km.[145] Both polar caps show spiral troughs, which recent analysis of SHARAD ice penetrating radar has shown are a result of katabatic winds that spiral due to the Coriolis effect.[146][147]

The seasonal frosting of areas near the southern ice cap results in the formation of transparent 1-metre-thick slabs of dry ice above the ground. With the arrival of spring, sunlight warms the subsurface and pressure from subliming CO2 builds up under a slab, elevating and ultimately rupturing it. This leads to geyser-like eruptions of CO2 gas mixed with dark basaltic sand or dust. This process is rapid, observed happening in the space of a few days, weeks or months, a rate of change rather unusual in geology especially for Mars. The gas rushing underneath a slab to the site of a geyser carves a spiderweb-like pattern of radial channels under the ice, the process being the inverted equivalent of an erosion network formed by water draining through a single plughole.[148][149]

Although better remembered for mapping the Moon, Johann Heinrich Mdler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mdler combined ten years of observations and drew the first map of Mars.[150]

Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; small valleys are named for rivers.[151]

Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, Nix Olympica (the snows of Olympus) has become Olympus Mons (Mount Olympus).[152] The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albedo. The paler plains covered with dust and sand rich in reddish iron oxides were once thought of as Martian "continents" and given names like Arabia Terra (land of Arabia) or Amazonis Planitia (Amazonian plain). The dark features were thought to be seas, hence their names Mare Erythraeum, Mare Sirenum and Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum.[153] The permanent northern polar ice cap is named Planum Boreum. The southern cap is called Planum Australe.[154]

Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mdler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft Mariner 9 provided extensive imagery of Mars in 1972, a small crater (later called Airy-0), located in the Sinus Meridiani ("Middle Bay" or "Meridian Bay"), was chosen by Merton Davies, Harold Masursky, and Grard de Vaucouleurs for the definition of 0.0 longitude to coincide with the original selection.[155][156][157]

Because Mars has no oceans and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the areoid[158] of Mars, analogous to the terrestrial geoid.[159] Zero altitude was defined by the height at which there is 610.5Pa (6.105mbar) of atmospheric pressure.[160] This pressure corresponds to the triple point of water, and it is about 0.6% of the sea level surface pressure on Earth (0.006 atm).[161]

For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains.[162]

The shield volcano Olympus Mons (Mount Olympus) is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes. The edifice is over 600km (370mi) wide.[163][164] Because the mountain is so large, with complex structure at its edges, allocating a height to it is difficult. Its local relief, from the foot of the cliffs which form its northwest margin to its peak, is over 21km (13mi),[164] a little over twice the height of Mauna Kea as measured from its base on the ocean floor. The total elevation change from the plains of Amazonis Planitia, over 1,000km (620mi) to the northwest, to the summit approaches 26km (16mi),[165] roughly three times the height of Mount Everest, which in comparison stands at just over 8.8 kilometres (5.5mi). Consequently, Olympus Mons is either the tallest or second-tallest mountain in the Solar System; the only known mountain which might be taller is the Rheasilvia peak on the asteroid Vesta, at 2025km (1216mi).[166]

The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If this is the case, the Northern Hemisphere of Mars would be the site of an impact crater 10,600 by 8,500 kilometres (6,600 by 5,300mi) in size, or roughly the area of Europe, Asia, and Australia combined, surpassing Utopia Planitia and the Moon's South PoleAitken basin as the largest impact crater in the Solar System.[167][168][169]

Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of 5 kilometres (3.1mi) or greater have been found.[170] The largest exposed crater is Hellas, which is 2,300 kilometres (1,400mi) wide and 7,000 metres (23,000ft) deep, and is a light albedo feature clearly visible from Earth.[171][172] There are other notable impact features, such as Argyre, which is around 1,800 kilometres (1,100mi) in diameter,[173] and Isidis, which is around 1,500 kilometres (930mi) in diameter.[174] Due to the smaller mass and size of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter.[175]

Martian craters can have a morphology that suggests the ground became wet after the meteor impacted.[176]

The large canyon, Valles Marineris (Latin for "Mariner Valleys", also known as Agathodaemon in the old canal maps[177]), has a length of 4,000 kilometres (2,500mi) and a depth of up to 7 kilometres (4.3mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 kilometres (277mi) long and nearly 2 kilometres (1.2mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 kilometres (93mi) of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement.[178][179]

Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons.[180] The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters".[181] Cave entrances measure from 100 to 252 metres (328 to 827ft) wide and they are estimated to be at least 73 to 96 metres (240 to 315ft) deep. Because light does not reach the floor of most of the caves, it is possible that they extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 metres (430ft) deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface.[182][183]

Mars lost its magnetosphere 4billion years ago,[184] possibly because of numerous asteroid strikes,[185] so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer.[186] Both Mars Global Surveyor and Mars Express have detected ionised atmospheric particles trailing off into space behind Mars,[184][187] and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30Pa (0.0044psi) on Olympus Mons to over 1,155Pa (0.1675psi) in Hellas Planitia, with a mean pressure at the surface level of 600Pa (0.087psi).[188] The highest atmospheric density on Mars is equal to that found 35 kilometres (22mi)[189] above Earth's surface. The resulting mean surface pressure is only 0.6% of that of Earth 101.3kPa (14.69psi). The scale height of the atmosphere is about 10.8 kilometres (6.7mi),[190] which is higher than Earth's 6 kilometres (3.7mi), because the surface gravity of Mars is only about 38% of Earth's.[191]

The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water.[2][192][186] The atmosphere is quite dusty, containing particulates about 1.5 m in diameter which give the Martian sky a tawny color when seen from the surface.[193] It may take on a pink hue due to iron oxide particles suspended in it.[27] The concentration of methane in the Martian atmosphere fluctuates from about 0.24 ppb during the northern winter to about 0.65 ppb during the summer.[194] Estimates of its lifetime range from 0.6 to 4 years,[195][196] so its presence indicates that an active source of the gas must be present. Methane could be produced by non-biological process such as serpentinization involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars,[197] or by Martian life.[198]

Compared to Earth, its higher concentration of atmospheric CO2 and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the Perseverance rover, researchers concluded that the speed of sound there is approximately 240m/s for frequencies below 240Hz, and 250m/s for those above.[200][201]

Auroras have been detected on Mars.[202][203][204] Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth;[205] rather than being mostly restricted to polar regions, a Martian aurora can encompass the planet.[206] In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25 times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month.[206][207]

Of all the planets in the Solar System, the seasons of Mars are the most Earth-like, due to the similar tilts of the two planets' rotational axes. The lengths of the Martian seasons are about twice those of Earth's because Mars's greater distance from the Sun leads to the Martian year being about two Earth years long. Martian surface temperatures vary from lows of about 110C (166F) to highs of up to 35C (95F) in equatorial summer.[17] The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure, and the low thermal inertia of Martian soil.[208] The planet is 1.52 times as far from the Sun as Earth, resulting in just 43% of the amount of sunlight.[209][210]

If Mars had an Earth-like orbit, its seasons would be similar to Earth's because its axial tilt is similar to Earth's. The comparatively large eccentricity of the Martian orbit has a significant effect. Mars is near perihelion when it is summer in the Southern Hemisphere and winter in the north, and near aphelion when it is winter in the Southern Hemisphere and summer in the north. As a result, the seasons in the Southern Hemisphere are more extreme and the seasons in the northern are milder than would otherwise be the case. The summer temperatures in the south can be warmer than the equivalent summer temperatures in the north by up to 30C (54F).[211]

Mars has the largest dust storms in the Solar System, reaching speeds of over 160km/h (100mph). These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.[212]

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Mars - Wikipedia

Noora Alsaeed has often thought about building a snowman on Mars.

Lets go over that again. A snowman on Mars? That desertlike, desolate planet over there? The one covered in sand? What an unusual daydream.

But Alsaeed knows a few things that the rest of us dont. She is a planetary scientist at the University of Colorado at Boulder whose work relies on data from a NASA spacecraft that orbits Mars. She studies the red planets polar regions and the peculiar molecules suspended in the atmosphere above them. She knows that on Mars, it snows.

Just like Earth, Mars has seasons, and during the winterabout twice as long as oursicy crystals cascade from the clouds and accumulate on the frigid surface. This sounds unbelievable, given that Mars is notoriously dry. But Mars gets around that little technicality by substituting intricate, six-sided water snow for something else. The Martian atmosphere, many times thinner than Earths, is primarily composed of carbon dioxide. In the most bitter conditions, the carbon dioxide transforms from a gas into small, cube-shaped crystals of icespecifically dry ice, the kind we earthlings use to set a spooky scene on Halloween. The ice is too heavy to remain in the Martian sky, so it flurries down, settling in shallow piles on the red planet.

Mars is the planet that, aside from Earth, has likely made the largest impression on the public imagination. Were well acquainted with Mars as the planet with all the rovers, the place where Elon Musk wants people to make a second home, the obvious next destination now that humans have been to the moon. But under all that hype are subtler, downright fascinating details about the fourth planet from the sun, such as its mesmerizing soundscape and its richly textured rock formations, layered like mille-feuille. Carbon-dioxide snow is just one of Marss many curiosities.

Read: Marss soundscape is strangely beautiful

Scientists began to suspect that Marss polar regions could become cold enough to turn carbon dioxide into snow as early as the 1800s, Paul Hayne, a planetary scientist at CU Boulder who studies Martian snowfall, told me. A NASA mission in the 1970s made observations that would later be interpreted as the first signs of carbon-dioxide snowfall. In 2008, a spacecraft that landed in Marss northern plains detected evidence of snowthe water-ice kind!falling from the atmosphere. But there was no evidence that the water snow actually reached the ground; the air on Mars is so thin that the water sublimates into a gas before the crystals can touch the surface.

The Mars Reconnaissance Orbiter, which has been circling Mars for more than 15 years, has captured carbon-dioxide snow reaching the surface, though. (Scientists dont have photographic or video evidence of carbon-dioxide snowfall, only detections made with laser technology and observations in wavelengths that are invisible to our eyes. Since most of the snow on Mars falls in the darkness of polar night, we need to use wavelengths of radiation outside of the visible spectrum, Hayne said.) The snow even accumulates, mostly near sloped areas such as cliff sides and crater edges, Sylvain Piqueux, a research scientist at NASAs Jet Propulsion Laboratory who studies Mars, told me. He said that enough of it piles up tohypotheticallysnowshoe in.

That idea tickles the imagination. What might it be like to stand on the Martian surface in the middle of winter, the temperatures finally cold enough to loose some molecules from the sky? Snowfall occurs only during the cold Martian night, so if you brought some night-vision goggles, youd see that you were enveloped in a bright haze. Carbon-dioxide snowflakes are tiny, smaller than the width of a strand of hairmuch smaller than their six-sided, water-ice counterparts. It wouldnt look as magical as it does on Earth, Alsaeed said.

But a Martian blizzard would be lovely in its own way. It would be extraordinarily quiet, Hayne said. You might even be able to catch the sound of little carbon-dioxide snow-cubes falling onto the ground. A gust of wind could kick up an opaque column of glittering snow, he said. Glittering and snowtwo words that may reshape your mental picture of Mars.

Read: Weve never seen Mars quite like this

So if astronauts could, in theory, snowshoe on the red planet, what else could they do? Skiing is likely out, Hayne said. Part of what makes skiing possible on Earth is that a thin film of liquid water forms on the surfaces of the ice particles as your ski creates friction, lubricating your motion, he said. On Mars, that friction would cause icy particles to turn into vapor and billow away, which would probably make your skis a bit squirrelly.

The experts dont really know whether other classic winter activities could take place on Mars. The idea of dealing with snow thats made of CO2 is just so alien to me, Alsaeed said. Its gonna be a completely different ball game. Piqueux isnt sure whether carbon-dioxide snow would clump enough to form a snowball, let alone a snowman; dry ice is not exactly a chemical enigma, but how the stuff behaves under Martian conditions is more mysterious, he said. At the very least, you might manage a snow angel. And as for opening your mouth wide to catch a cube-shaped snowflake? You cant stick your tongue out on Mars, ever! Hayne said. (Sorry, I had to ask!)

There is much to learn. Snow might be a universal process for [worlds] with an atmosphere, Piqueux said. Learning how it works might tell us quite a bit about planetswhat shapes their surface, how they evolve, and what they look like. Scientists theorize that Mars was more like Earth a few billion years agowarm and balmy, with real lakes and seas. Perhaps it snowed more back then too, with chunky flakes of frozen water, and the influence of that ancient precipitation remains embedded at the planets poles.

Many decades ago, well before any space robots arrived on Mars, scientists imagined the red planet to be a bustling place, believing that the surface markings they saw through their telescopes were evidence of intelligent engineering. The astronomer Percival Lowell wrote at length about these markings, which he called canals, in The Atlantic in 1895, sparking in the public imagination the tantalizing promise of an inhabited Mars. That ended up not being the case: Any life that may have arisen on Mars is either long dead or hiding out of view, buried away from the glare of the sun. The dissimilarity to Earth was almost disappointing.

From the May 1895 issue: Mars

But still, there are familiar echoes, as Lowell himself recognized. If astronomy teaches anything, it teaches that man is but a detail in the evolution of the universe, and that resemblant though diverse details are inevitably to be expected in the host of orbs around him, he wrote. He learns that though he will probably never find his double anywhere, he is destined to discover any number of cousins scattered through space. Cousins like Martian snowperhaps not enough to make a genuine snowman, but certainly enough to stir our imagination from millions of miles away.

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Mars Gives Snow an Alien Twist - The Atlantic

China's Zhurong Mars rover remains silent despite being expected to wake up in December but there's still hope that the vehicle could rise from its slumber.

Zhurong is part of Tianwen 1, China's first interplanetary mission, which also includes a Mars orbiter. The rover touched down on the Red Planet's Utopia Planitia back in May 2021 and conducted a range of science and exploration activities before entering a dormant state in May 2022 to wait out the cold, harsh winter in the northern hemisphere of Mars.

Zhurong was expected to wake up in December, around the time of the Mars spring equinox. So far, however, there has been silence from both the rover and its operators in China, with reports that the spacecraft could be in trouble.

Related: China's 1st Mars rover and Tianwen 1 orbiter may have gone silent

Yet hope remains that Zhurong is simply experiencing colder than expected conditions and may still wake itself up and resume activities.

Jia Yang, a Tianwen 1 mission deputy chief designer, told (opens in new tab) reporters in September 2022 that Zhurong would wake up autonomously when two conditions are met. These are a temperature of greater than 5 degrees Fahrenheit (minus 15 degrees Celsius) and energy generation of greater than 140 watts.

Weather data from NASA's Perseverance rover which is nuclear-powered and has not needed to hibernate reveals that temperatures in Mars' Jezero Crater have only briefly risen higher than this lowest heat requirement. Perseverance is also some seven degrees latitude south of Zhurong and thus closer to the Martian equator, meaning it may also be experiencing slightly more favorable conditions than China's rover.

The other factor affecting Zhurong is that dust storms may have deposited Martian sand onto Zhurong's solar arrays, hindering its ability to generate power and wake itself up. The rover's butterfly-shaped solar panels use anti-dust material, and Zhurong is equipped with a vibrating function to shake off accumulated dust. However, the rover will need to be active to employ this latter measure.

Time will tell if Zhurong will roll along the Martian surface once more, but the mission has already been a huge success. The landing made China the second country to successfully operate a rover on Mars after the U.S., and both Zhurong and the Tianwen 1 orbiter have completed their primary missions.

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Will China's Zhurong Mars rover wake from worrying hibernation ...

Noon Energy, which has developed ultra-low-cost, high energy density carbon-oxygen battery technology for long-duration energy storage for solar and wind power, today announced that its secured $28 million in Series A financing to commercialize its technology.

Boston-based Clean Energy Ventures and Aramco Ventures new Sustainability Fund (as in, Saudi oil Aramco) led the round. Noon Energy previously closed on a $3million seed round in April 2021.

Chris Graves, Noon Energys founder andCEO (pictured above center), launched the company in 2018 after helping to develop NASAs Mars Perseverance rover MOXIE device, which produces oxygen from the Martian carbon dioxide atmosphere.

The 10-person team at Noon Energy has since developed a battery that stores energy in carbon and oxygen using nature-based chemistry principles. So metals such as lithium and cobalt arent needed, and Noon Energy says its battery requires just 1% of other critical elements compared to lithium-ion batteries.

The Palo Alto-based startup says its battery offers more than 100 hours of energy storage at at one-tenth the cost of lithium-ion batteries for long-duration storage. And because its extremely dense, that means a compact footprint three times smaller than current lithium-ion batteries.

In the past 14 months, Noon Energy says its team has achieved a 50x scale-up of its core technology and that it plans to bring its battery to market in two years.

David Miller, cofounder and managing partner at Clean Energy Ventures, said:

Noon Energys technology has far greater potential as modular, scalable, and low-cost long-duration energy storage than any other approach weve ever seen, and therefore can enable any system, from a single home, to an entire grid, to run on 100% solar and wind.

Noons approach to long-duration storage is not only inspiring but proven, and we look forward to supporting this world-class team as they continue to scale and enable 100% renewables penetration.

Noon Energys website gives very little away, but its hiring in order to scale up. Its next move will be to build demonstration products to test its carbon-oxygen batteries in the field.

Read more: This game-changing big brick toaster battery is now on the market

Photo: Noon Energy

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A Mars rover scientist is about to scale carbon-oxygen batteries

Proposed NASA Mars communications satellite

The Next Mars Orbiter (NeMO, earlier known as the Mars 2022 orbiter) is a proposed NASA Mars communications satellite with high-resolution imaging payload and two solar-electric ion thrusters.[2][3]

The orbiter was initially proposed to be launched in September 2022 to link ground controllers with rovers and landers and extend mapping capabilities expected to be lost when the Mars Reconnaissance Orbiter and 2001 Mars Odyssey stop functioning,[2][1] but officials elected to focus on flying the Perseverance rover first to cache various samples for a later sample-return mission that will incorporate a Mars telecom orbiter, now envisioned for the late 2020s.[4]

Key features under study include solar electric ion drive engines, better solar arrays, and broadband laser communications (optic communication) between Earth and Mars.[2][3][5]

The orbiter is conceptually similar to the Mars Telecommunications Orbiter, canceled in 2005,[3] and could be a technology precursor for a future round-trip sample return mission[6] and human expeditions to Mars.[2][7] Robert Lock is leading the concept studies for the 2022 orbiter.[2][7]

Concern in NASA is that the currently used relay satellites, 2001 Mars Odyssey and Mars Reconnaissance Orbiter, may stop functioning, resulting in the need to press the MAVEN science orbiter into use as a backup telecommunications relay.[2][3][8] Since the highly elliptical orbit of MAVEN limits its usefulness as a relay for surface operations,[9][10] NASA will lower its orbit from 6,200 (3,900) to between 4,000 and 4,500 kilometers (2,500 and 2,800mi) altitude, where it can serve as a relay while continuing its science mission.[11]

Another suggested feature under study is "the sample rendezvous capture and return capability". The samples cached by the Mars 2020 rover would be placed in Mars orbit by a future Mars ascent vehicle. From there, the orbiter would rendezvous, transfer the samples into a capsule and send it back to Earth.[12]

The proposed orbiter would be propelled with two solar-electric ion thrusters; one engine would be active while the other one would be a spare.[1] Electrical power to the engines would be provided by advanced solar arrays that generate 20kW.[1]

An ion engine would give the spacecraft significant orbital flexibility for long-term support of future missions,[1] opportunistic flybys of Phobos and Deimos,[1] as well as the added capability of orbit supportrendezvous and capturefor a sample return mission.[1] An ion engine would also allow access to multiple latitudes and altitudes to optimize relay contacts.

The orbiter mission has been suggested by the Planetary Science Decadal Survey to be one of three missions of the proposed Mars Sample Return (MSR) campaign.[12][14] Samples would be collected and cached by the Mars 2020 mission and would be left on the surface of Mars for possible later retrieval.[14] The orbiter would be launched on a medium-class vehicle, reaching Mars in about nine months and set to aerobrake down to a 500km (310mi) circular orbit over six to nine months.[14]

The third mission of the proposed MSR campaign, the lander, would nominally be launched two years after the orbiter launch. The lander would deploy a "fetch rover" to retrieve the sample caches. A container holding the samples would be launched by a two-stage, solid-fueled Mars ascent vehicle (MAV) and placed in a 500-km orbit comparable with the new orbiter and perform a rendezvous while in Mars orbit.[14] The container would be transferred to an Earth entry vehicle (EEV) which would bring it to Earth, enter the atmosphere under a parachute and hard-land for retrieval and analyses in specially designed safe laboratories.[12][14]

Some NASA officials consider the Mars 2022 orbiter an "essential orbital support for sample return", "significant" in maintaining the Martian communications infrastructure, and desirable for the continuity in remote sensing.[15] The President's FY2017 Budget provided $10 million to begin early conceptual work on the proposed Mars orbiter.[15][16] In July 2016, the Jet Propulsion Laboratory awarded five $400,000[1] sub-contracts to conduct concept studies. The five engineering companies are Boeing, Lockheed Martin Space Systems, Northrop Grumman Aerospace Systems, Orbital ATK, and Space Systems/Loral.[17][18]

However, in August 2017, Jim Green of NASA's Planetary Science Division stated that a 2022 launch for the orbiter was "probably off the table", as it would be too difficult to assemble an orbiter with all of the desired features in that time frame.[19] Jim Watzin of NASA's Mars Exploration Program stated in September 2017 that the orbiter may have to be cancelled, citing that "the likelihood of all of the relay orbiters failing is so low that no more investments are needed for that purpose."[20]

In February 2018, NASA announced that it was moving ahead with plans to alter the orbit of the MAVEN orbiter to have it serve as a communications relay. It will be lowered to 4,0004,500 kilometers (2,5002,800mi) altitude, where it can serve as a relay while allowing it to continue its science mission.[21] In March 2018, NASA officials decided that the aging Mars Reconnaissance Orbiter (MRO) will be managed such that it will continue service for about ten more years, and the program will now focus its resources on flying a sample-return mission first.[4] The 2001 Mars Odyssey orbiter will also be managed to continue operating until about 2025.[22] A new Mars relay orbiter is likely to take part in the sample-return architecture envisioned for the late 2020s.[4]

[needs update]

Continued here:
Next Mars Orbiter - Wikipedia

Occupy Mars is a highly technical, open-world sandbox game about Mars colonization inspired by the most promising technologies and companies that are working toward becoming a multi-planet species. Build and upgrade your base, discover new amazing regions, conduct mining operations, retrieve water, generate oxygen, grow crops, fix broken parts, and learn how to survive on Mars!

Have you ever dreamt about visiting Mars? We always do! There are so many things to see and discover on the red planet, so many exciting technologies to be created, and so many challenges to overcome! If humanity can do this, we can become a multi-planet civilization!

Build and upgrade your base. Make sure that there is enough water, oxygen, power, and food to survive.

Build greenhouses, oxygen tanks, fuel generators, connect all the pipes and cables, and remember about proper cable management. Grow your own food.

Fix broken parts using realistic electronic components and tools. Learn the basics soldering, using hot air, electronic measurement tools, and all the details necessary to fix your equipment.

Explore different regions of Mars while searching for valuable resources, discover mining sites, and find the best place to build a city.

Remember that you need to find a relatively leveled area with good access to underground water in a place where temperatures don't drop too much during the night.

Experience an open-world sandbox game with a realistic day/night cycle and overcome real challenges that colonists face. Build solar arrays and batteries for energy storage, upgrade them, and find the optimal way to power your colony.

Upgrade your vehicles and equipment in your garage. Organize your workshop and modify your rover. Change crane hydraulics, operate the robotic arm, dig for valuable resources, build mining rigs, and more...

Occupying Mars is not always easy. Sometimes things will explode, break or not go exactly as planned. Learn to cope with "Rapid Unscheduled Disassembly. Sometimes you have to really act quickly before you run out of air, food, or energy.

...but most importantly HAVE FUN on Mars!

Our previous game Rover Mechanic Simulator:https://store.steampowered.com/app/864680/

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Occupy Mars: The Game on Steam

Scientific assessments on the microbial habitability of Mars

The possibilities of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms, but habitable conditions do not necessarily indicate life.[1][2]

Scientific searches for evidence of life began in the 19th century and continue today via telescopic investigations and deployed probes. While early work focused on phenomenology and bordered on fantasy, the modern scientific inquiry has emphasized the search for water, chemical biosignatures in the soil and rocks at the planet's surface, and biomarker gases in the atmosphere.[3]

Mars is of particular interest for the study of the origins of life because of its similarity to the early Earth. This is especially true since Mars has a cold climate and lacks plate tectonics or continental drift, so it has remained almost unchanged since the end of the Hesperian period. At least two-thirds of Mars's surface is more than 3.5billion years old, and Mars may thus hold the best record of the prebiotic conditions leading to life, even if life does not or has never existed there,[4][5] which might have started developing as early as 4.48billion years ago.[6]

Following the confirmation of the past existence of surface liquid water, the Curiosity, Perseverance and Opportunity rovers started searching for evidence of past life, including a past biosphere based on autotrophic, chemotrophic, or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[7][8][9][10] The search for evidence of habitability, taphonomy (related to fossils), and organic compounds on Mars is now a primary NASA and ESA objective.

The findings of organic compounds inside sedimentary rocks and of boron on Mars are of interest as they are precursors for prebiotic chemistry. Such findings, along with previous discoveries that liquid water was clearly present on ancient Mars, further supports the possible early habitability of Gale Crater on Mars.[11][12] Currently, the surface of Mars is bathed with ionizing radiation, and Martian soil is rich in perchlorates toxic to microorganisms.[13][14] Therefore, the consensus is that if life existsor existedon Mars, it could be found or is best preserved in the subsurface, away from present-day harsh surface processes.

In June 2018, NASA announced the detection of seasonal variation of methane levels on Mars. Methane could be produced by microorganisms or by geological means.[15] The European ExoMars Trace Gas Orbiter started mapping the atmospheric methane in April 2018, and the 2022 ExoMars rover Rosalind Franklin was planned to drill and analyze subsurface samples before the programme's indefinite suspension, while the NASA Mars 2020 rover Perseverance, having landed successfully, will cache dozens of drill samples for their potential transport to Earth laboratories in the late 2020s or 2030s. As of February 8, 2021, an updated status of studies considering the possible detection of lifeforms on Venus (via phosphine) and Mars (via methane) was reported.[16]

Mars's polar ice caps were discovered in the mid-17th century.[citation needed] In the late 18th century, William Herschel proved they grow and shrink alternately, in the summer and winter of each hemisphere. By the mid-19th century, astronomers knew that Mars had certain other similarities to Earth, for example that the length of a day on Mars was almost the same as a day on Earth. They also knew that its axial tilt was similar to Earth's, which meant it experienced seasons just as Earth doesbut of nearly double the length owing to its much longer year. These observations led to increasing speculation that the darker albedo features were water and the brighter ones were land, whence followed speculation on whether Mars may be inhabited by some form of life.[17]

In 1854, William Whewell, a fellow of Trinity College, Cambridge, theorized that Mars had seas, land and possibly life forms.[18] Speculation about life on Mars exploded in the late 19th century, following telescopic observation by some observers of apparent Martian canalswhich were later found to be optical illusions. Despite this, in 1895, American astronomer Percival Lowell published his book Mars, followed by Mars and its Canals in 1906,[19] proposing that the canals were the work of a long-gone civilization.[20] This idea led British writer H. G. Wells to write The War of the Worlds in 1897, telling of an invasion by aliens from Mars who were fleeing the planet's desiccation.[21]

Spectroscopic analysis of Mars's atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen were present in the Martian atmosphere.[22] The influential observer Eugne Antoniadi used the 83-cm (32.6inch) aperture telescope at Meudon Observatory at the 1909 opposition of Mars and saw no canals, the outstanding photos of Mars taken at the new Baillaud dome at the Pic du Midi observatory also brought formal discredit to the Martian canals theory in 1909,[23] and the notion of canals began to fall out of favor.[22]

Chemical, physical, geological, and geographic attributes shape the environments on Mars. Isolated measurements of these factors may be insufficient to deem an environment habitable, but the sum of measurements can help predict locations with greater or lesser habitability potential.[24] The two current ecological approaches for predicting the potential habitability of the Martian surface use 19 or 20 environmental factors, with an emphasis on water availability, temperature, the presence of nutrients, an energy source, and protection from solar ultraviolet and galactic cosmic radiation.[25][26]

Scientists do not know the minimum number of parameters for determination of habitability potential, but they are certain it is greater than one or two of the factors in the table below.[24] Similarly, for each group of parameters, the habitability threshold for each is to be determined.[24] Laboratory simulations show that whenever multiple lethal factors are combined, the survival rates plummet quickly.[27] There are no full-Mars simulations published yet that include all of the biocidal factors combined.[27] Furthermore, the possibility of Martian life having a far different biochemistry and habitability requirements than the terrestrial biosphere is an open question.

Recent models have shown that, even with a dense CO2 atmosphere, early Mars was colder than Earth has ever been.[28][29][30][31] Transiently warm conditions related to impacts or volcanism could have produced conditions favoring the formation of the late Noachian valley networks, even though the mid-late Noachian global conditions were probably icy. Local warming of the environment by volcanism and impacts would have been sporadic, but there should have been many events of water flowing at the surface of Mars.[31] Both the mineralogical and the morphological evidence indicates a degradation of habitability from the mid Hesperian onward. The exact causes are not well understood but may be related to a combination of processes including loss of early atmosphere, or impact erosion, or both.[31]

The loss of the Martian magnetic field strongly affected surface environments through atmospheric loss and increased radiation; this change significantly degraded surface habitability.[33] When there was a magnetic field, the atmosphere would have been protected from erosion by the solar wind, which would ensure the maintenance of a dense atmosphere, necessary for liquid water to exist on the surface of Mars.[34] The loss of the atmosphere was accompanied by decreasing temperatures. Part of the liquid water inventory sublimed and was transported to the poles, while the rest becametrapped in permafrost, a subsurface ice layer.[31]

Observations on Earth and numerical modeling have shown that a crater-forming impact can result in the creation of a long-lasting hydrothermal system when ice is present in the crust. For example, a 130km large crater could sustain an active hydrothermal system for up to 2million years, that is, long enough for microscopic life to emerge,[31] but unlikely to have progressed any further down the evolutionary path.[35]

Soil and rock samples studied in 2013 by NASA's Curiosity rover's onboard instruments brought about additional information on several habitability factors.[36] The rover team identified some of the key chemical ingredients for life in this soil, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and possibly carbon, as well as clay minerals, suggesting a long-ago aqueous environmentperhaps a lake or an ancient streambedthat had neutral acidity and low salinity.[36] On December 9, 2013, NASA reported that, based on evidence from Curiosity studying Aeolis Palus, Gale Crater contained an ancient freshwater lake which could have been a hospitable environment for microbial life.[37][38] The confirmation that liquid water once flowed on Mars, the existence of nutrients, and the previous discovery of a past magnetic field that protected the planet from cosmic and solar radiation,[39][40] together strongly suggest that Mars could have had the environmental factors to support life.[41][42] The assessment of past habitability is not in itself evidence that Martian life has ever actually existed. If it did, it was probably microbial, existing communally in fluids or on sediments, either free-living or as biofilms, respectively.[33] The exploration of terrestrial analogues provide clues as to how and where best look for signs of life on Mars.[43]

Impactite, shown to preserve signs of life on Earth, was discovered on Mars and could contain signs of ancient life, if life ever existed on the planet.[44]

On June 7, 2018, NASA announced that the Curiosity rover had discovered organic molecules in sedimentary rocks dating to three billion years old.[45][46] The detection of organic molecules in rocks indicate that some of the building blocks for life were present.[47][48]

Conceivably, if life exists (or existed) on Mars, evidence of life could be found, or is best preserved, in the subsurface, away from present-day harsh surface conditions.[49] Present-day life on Mars, or its biosignatures, could occur kilometers below the surface, or in subsurface geothermal hot spots, or it could occur a few meters below the surface. The permafrost layer on Mars is only a couple of centimeters below the surface, and salty brines can be liquid a few centimeters below that but not far down. Water is close to its boiling point even at the deepest points in the Hellas basin, and so cannot remain liquid for long on the surface of Mars in its present state, except after a sudden release of underground water.[50][51][52]

So far, NASA has pursued a "follow the water" strategy on Mars and has not searched for biosignatures for life there directly since the Viking missions. The consensus by astrobiologists is that it may be necessary to access the Martian subsurface to find currently habitable environments.[49]

In 1965, the Mariner 4 probe discovered that Mars had no global magnetic field that would protect the planet from potentially life-threatening cosmic radiation and solar radiation; observations made in the late 1990s by the Mars Global Surveyor confirmed this discovery.[53] Scientists speculate that the lack of magnetic shielding helped the solar wind blow away much of Mars's atmosphere over the course of several billion years.[54] As a result, the planet has been vulnerable to radiation from space for about 4billion years.[55]

Recent in-situ data from Curiosity rover indicates that ionizing radiation from galactic cosmic rays (GCR) and solar particle events (SPE) may not be a limiting factor in habitability assessments for present-day surface life on Mars. The level of 76 mGy per year measured by Curiosity is similar to levels inside the ISS.[56]

Curiosity rover measured ionizing radiation levels of 76 mGy per year.[57] This level of ionizing radiation is sterilizing for dormant life on the surface of Mars. It varies considerably in habitability depending on its orbital eccentricity and the tilt of its axis. If the surface life has been reanimated as recently as 450,000 years ago, then rovers on Mars could find dormant but still viable life at a depth of one meter below the surface, according to an estimate.[58] Even the hardiest cells known could not possibly survive the cosmic radiation near the surface of Mars since Mars lost its protective magnetosphere and atmosphere.[59][60] After mapping cosmic radiation levels at various depths on Mars, researchers have concluded that over time, any life within the first several meters of the planet's surface would be killed by lethal doses of cosmic radiation.[59][61][62] The team calculated that the cumulative damage to DNA and RNA by cosmic radiation would limit retrieving viable dormant cells on Mars to depths greater than 7.5 meters below the planet's surface.[61]Even the most radiation-tolerant terrestrial bacteria would survive in dormant spore state only 18,000 years at the surface; at 2 metersthe greatest depth at which the ExoMars rover will be capable of reachingsurvival time would be 90,000 to half a million years, depending on the type of rock.[63]

Data collected by the Radiation assessment detector (RAD) instrument on board the Curiosity rover revealed that the absorbed dose measured is 76 mGy/year at the surface,[64] and that "ionizing radiation strongly influences chemical compositions and structures, especially for water, salts, and redox-sensitive components such as organic molecules."[64] Regardless of the source of Martian organic compounds (meteoric, geological, or biological), its carbon bonds are susceptible to breaking and reconfiguring with surrounding elements by ionizing charged particle radiation.[64] These improved subsurface radiation estimates give insight into the potential for the preservation of possible organic biosignatures as a function of depth as well as survival times of possible microbial or bacterial life forms left dormant beneath the surface.[64] The report concludes that the in situ "surface measurementsand subsurface estimatesconstrain the preservation window for Martian organic matter following exhumation and exposure to ionizing radiation in the top few meters of the Martian surface."[64]

In September 2017, NASA reported Radiation levels on the surface of the planet Mars were temporarily doubled and were associated with an aurora 25 times brighter than any observed earlier, due to a major, and unexpected, solar storm in the middle of the month.[65]

On UV radiation, a 2014 report concludes [66] that "[T]he Martian UV radiation environment is rapidly lethal to unshielded microbes but can be attenuated by global dust storms and shielded completely by < 1 mm of regolith or by other organisms." In addition, laboratory research published in July 2017 demonstrated that UV irradiated perchlorates cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60seconds of exposure.[67][68] The penetration depth of UV radiation into soils is in the sub-millimeter to millimeter range and depends on the properties of the soil.[68]

The Martian regolith is known to contain a maximum of 0.5% (w/v) perchlorate (ClO4) that is toxic for most living organisms,[69] but since they drastically lower the freezing point of water and a few extremophiles can use it as an energy source (see Perchlorates - Biology) and grow at concentrations of up to 30% (w/v) sodium perchlorate[70] by physiologically adapting to increasing perchlorate concentrations,[71] it has prompted speculation of what their influence would be on habitability.[67][70][72][73][74]

Research published in July 2017 shows that when irradiated with a simulated Martian UV flux, perchlorates become even more lethal to bacteria (bactericide). Even dormant spores lost viability within minutes.[67] In addition, two other compounds of the Martian surface, iron oxides and hydrogen peroxide, act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60seconds of exposure.[67][68] It was also found that abraded silicates (quartz and basalt) lead to the formation of toxic reactive oxygen species.[75] The researchers concluded that "the surface of Mars is lethal to vegetative cells and renders much of the surface and near-surface regions uninhabitable."[76] This research demonstrates that the present-day surface is more uninhabitable than previously thought,[67][77] and reinforces the notion to inspect at least a few meters into the ground to ensure the levels of radiation would be relatively low.[77][78]

However, researcher Kennda Lynch discovered the first-known instance of a habitat containing perchlorates and perchlorates-reducing bacteria in an analog environment: a paleolake in Pilot Valley, Great Salt Lake Desert, Utah.[79] She has been studying the biosignatures of these microbes, and is hoping that the Mars Perseverance rover will find matching biosignatures at its Jezero Crater site.[80][81]

Recurrent slope lineae (RSL) features form on Sun-facing slopes at times of the year when the local temperatures reach above the melting point for ice. The streaks grow in spring, widen in late summer and then fade away in autumn. This is hard to model in any other way except as involving liquid water in some form, though the streaks themselves are thought to be a secondary effect and not a direct indication of the dampness of the regolith. Although these features are now confirmed to involve liquid water in some form, the water could be either too cold or too salty for life. At present they are treated as potentially habitable, as "Uncertain Regions, to be treated as Special Regions".).[82][83] They were suspected as involving flowing brines back then.[84][85][86][87]

The thermodynamic availability of water (water activity) strictly limits microbial propagation on Earth, particularly in hypersaline environments, and there are indications that the brine ionic strength is a barrier to the habitability of Mars. Experiments show that high ionic strength, driven to extremes on Mars by the ubiquitous occurrence of divalent ions, "renders these environments uninhabitable despite the presence of biologically available water."[88]

After carbon, nitrogen is arguably the most important element needed for life. Thus, measurements of nitrate over the range of 0.1% to 5% are required to address the question of its occurrence and distribution. There is nitrogen (as N2) in the atmosphere at low levels, but this is not adequate to support nitrogen fixation for biological incorporation.[89] Nitrogen in the form of nitrate could be a resource for human exploration both as a nutrient for plant growth and for use in chemical processes. On Earth, nitrates correlate with perchlorates in desert environments, and this may also be true on Mars. Nitrate is expected to be stable on Mars and to have formed by thermal shock from impact or volcanic plume lightning on ancient Mars.[90]

On March 24, 2015, NASA reported that the SAM instrument on the Curiosity rover detected nitrates by heating surface sediments. The nitrogen in nitrate is in a "fixed" state, meaning that it is in an oxidized form that can be used by living organisms. The discovery supports the notion that ancient Mars may have been hospitable for life.[90][91][92] It is suspected that all nitrate on Mars is a relic, with no modern contribution.[93] Nitrate abundance ranges from non-detection to 681 304mg/kg in the samples examined until late 2017.[93] Modeling indicates that the transient condensed water films on the surface should be transported to lower depths (10 m) potentially transporting nitrates, where subsurface microorganisms could thrive.[94]

In contrast, phosphate, one of the chemical nutrients thought to be essential for life, is readily available on Mars.[95]

Further complicating estimates of the habitability of the Martian surface is the fact that very little is known about the growth of microorganisms at pressures close to those on the surface of Mars. Some teams determined that some bacteria may be capable of cellular replication down to 25 mbar, but that is still above the atmospheric pressures found on Mars (range 114 mbar).[96] In another study, twenty-six strains of bacteria were chosen based on their recovery from spacecraft assembly facilities, and only Serratia liquefaciens strain ATCC 27592 exhibited growth at 7 mbar, 0C, and CO2-enriched anoxic atmospheres.[96]

Liquid water is a necessary but not sufficient condition for life as humans know it, as habitability is a function of a multitude of environmental parameters.[97] Liquid water cannot exist on the surface of Mars except at the lowest elevations for minutes or hours.[98][99] Liquid water does not appear at the surface itself,[100] but it could form in minuscule amounts around dust particles in snow heated by the Sun.[101][102][unreliable source?] Also, the ancient equatorial ice sheets beneath the ground may slowly sublimate or melt, accessible from the surface via caves.[103][104][105][106]

Water on Mars exists almost exclusively as water ice, located in the Martian polar ice caps and under the shallow Martian surface even at more temperate latitudes.[110][111] A small amount of water vapor is present in the atmosphere.[112] There are no bodies of liquid water on the Martian surface because its atmospheric pressure at the surface averages 600 pascals (0.087psi)about 0.6% of Earth's mean sea level pressureand because the temperature is far too low, (210K (63C)) leading to immediate freezing. Despite this, about 3.8billion years ago,[113] there was a denser atmosphere, higher temperature, and vast amounts of liquid water flowed on the surface,[114][115][116][117] including large oceans.[118][119][120][121][122]

It has been estimated that the primordial oceans on Mars would have covered between 36%[123] and 75% of the planet.[124] On November 22, 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.[107][108][109]Analysis of Martian sandstones, using data obtained from orbital spectrometry, suggests that the waters that previously existed on the surface of Mars would have had too high a salinity to support most Earth-like life. Tosca et al. found that the Martian water in the locations they studied all had water activity, aw 0.78 to 0.86a level fatal to most Terrestrial life.[125] Haloarchaea, however, are able to live in hypersaline solutions, up to the saturation point.[126]

In June 2000, possible evidence for current liquid water flowing at the surface of Mars was discovered in the form of flood-like gullies.[127][128] Additional similar images were published in 2006, taken by the Mars Global Surveyor, that suggested that water occasionally flows on the surface of Mars. The images showed changes in steep crater walls and sediment deposits, providing the strongest evidence yet that water coursed through them as recently as several years ago.

There is disagreement in the scientific community as to whether or not the recent gully streaks were formed by liquid water. Some suggest the flows were merely dry sand flows.[129][130][131] Others suggest it may be liquid brine near the surface,[132][133][134] but the exact source of the water and the mechanism behind its motion are not understood.[135]

In July 2018, scientists reported the discovery of a subglacial lake on Mars, 1.5km (0.93mi) below the southern polar ice cap, and extending sideways about 20km (12mi), the first known stable body of water on the planet.[136][137][138][139] The lake was discovered using the MARSIS radar on board the Mars Express orbiter, and the profiles were collected between May 2012 and December 2015.[140] The lake is centered at 193E, 81S, a flat area that does not exhibit any peculiar topographic characteristics but is surrounded by higher ground, except on its eastern side, where there is a depression.[136]

In May 2007, the Spirit rover disturbed a patch of ground with its inoperative wheel, uncovering an area 90% rich in silica.[141] The feature is reminiscent of the effect of hot spring water or steam coming into contact with volcanic rocks. Scientists consider this as evidence of a past environment that may have been favorable for microbial life and theorize that one possible origin for the silica may have been produced by the interaction of soil with acid vapors produced by volcanic activity in the presence of water.[142]

Based on Earth analogs, hydrothermal systems on Mars would be highly attractive for their potential for preserving organic and inorganic biosignatures.[143][144][145] For this reason, hydrothermal deposits are regarded as important targets in the exploration for fossil evidence of ancient Martian life.[146][147][148]

In May 2017, evidence of the earliest known life on land on Earth may have been found in 3.48-billion-year-old geyserite and other related mineral deposits (often found around hot springs and geysers) uncovered in the Pilbara Craton of Western Australia.[149][150] These findings may be helpful in deciding where best to search for early signs of life on the planet Mars.[149][150]

Methane (CH4) is chemically unstable in the current oxidizing atmosphere of Mars. It would quickly break down due to ultraviolet radiation from the Sun and chemical reactions with other gases. Therefore, a persistent presence of methane in the atmosphere may imply the existence of a source to continually replenish the gas.

Trace amounts of methane, at the level of several parts per billion (ppb), were first reported in Mars's atmosphere by a team at the NASA Goddard Space Flight Center in 2003.[151][152] Large differences in the abundances were measured between observations taken in 2003 and 2006, which suggested that the methane was locally concentrated and probably seasonal.[153] On June 7, 2018, NASA announced it has detected a seasonal variation of methane levels on Mars.[15][154][47][48][155][156][157][46]

The ExoMars Trace Gas Orbiter (TGO), launched in March 2016, began on April 21, 2018, to map the concentration and sources of methane in the atmosphere,[158][159] as well as its decomposition products such as formaldehyde and methanol. As of May 2019, the Trace Gas Orbiter showed that the concentration of methane is under detectable level (< 0.05 ppbv).[160][161]

Curiosity detected a cyclical seasonal variation in atmospheric methane.

The principal candidates for the origin of Mars's methane include non-biological processes such as water-rock reactions, radiolysis of water, and pyrite formation, all of which produce H2 that could then generate methane and other hydrocarbons via FischerTropsch synthesis with CO and CO2.[162] It has also been shown that methane could be produced by a process involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars.[163] Although geologic sources of methane such as serpentinization are possible, the lack of current volcanism, hydrothermal activity or hotspots[164] are not favorable for geologic methane.

Living microorganisms, such as methanogens, are another possible source, but no evidence for the presence of such organisms has been found on Mars,[165][166][167] until June 2019 as methane was detected by the Curiosity rover.[168] Methanogens do not require oxygen or organic nutrients, are non-photosynthetic, use hydrogen as their energy source and carbon dioxide (CO2) as their carbon source, so they could exist in subsurface environments on Mars.[169] If microscopic Martian life is producing the methane, it probably resides far below the surface, where it is still warm enough for liquid water to exist.[170]

Since the 2003 discovery of methane in the atmosphere, some scientists have been designing models and in vitro experiments testing the growth of methanogenic bacteria on simulated Martian soil, where all four methanogen strains tested produced substantial levels of methane, even in the presence of 1.0wt% perchlorate salt.[171]

A team led by Levin suggested that both phenomenamethane production and degradationcould be accounted for by an ecology of methane-producing and methane-consuming microorganisms.[172][173]

Research at the University of Arkansas presented in June 2015 suggested that some methanogens could survive in Mars's low pressure. Rebecca Mickol found that in her laboratory, four species of methanogens survived low-pressure conditions that were similar to a subsurface liquid aquifer on Mars. The four species that she tested were Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, and Methanococcus maripaludis.[169] In June 2012, scientists reported that measuring the ratio of hydrogen and methane levels on Mars may help determine the likelihood of life on Mars.[165][166] According to the scientists, "low H2/CH4 ratios (less than approximately 40)" would "indicate that life is likely present and active".[165] The observed ratios in the lower Martian atmosphere were "approximately 10 times" higher "suggesting that biological processes may not be responsible for the observed CH4".[165] The scientists suggested measuring the H2 and CH4 flux at the Martian surface for a more accurate assessment. Other scientists have recently reported methods of detecting hydrogen and methane in extraterrestrial atmospheres.[174][175]

Even if rover missions determine that microscopic Martian life is the seasonal source of the methane, the life forms probably reside far below the surface, outside of the rover's reach.[176]

In February 2005, it was announced that the Planetary Fourier Spectrometer (PFS) on the European Space Agency's Mars Express Orbiter had detected traces of formaldehyde in the atmosphere of Mars. Vittorio Formisano, the director of the PFS, has speculated that the formaldehyde could be the byproduct of the oxidation of methane and, according to him, would provide evidence that Mars is either extremely geologically active or harboring colonies of microbial life.[177][178] NASA scientists consider the preliminary findings well worth a follow-up but have also rejected the claims of life.[179][180]

The 1970s Viking program placed two identical landers on the surface of Mars tasked to look for biosignatures of microbial life on the surface. Of the four experiments performed by each Viking lander, only the 'Labeled Release' (LR) experiment gave a positive result for metabolism, while the other three did not detect organic compounds. The LR was a specific experiment designed to test only a narrowly defined critical aspect of the theory concerning the possibility of life on Mars; therefore, the overall results were declared inconclusive.[22] No Mars lander mission has found meaningful traces of biomolecules or biosignatures. The claim of extant microbial life on Mars is based on old data collected by the Viking landers, currently reinterpreted as sufficient evidence of life, mainly by Gilbert Levin,[181][182] Joseph D. Miller,[183] Navarro,[184] Giorgio Bianciardi and Patricia Ann Straat,[185] that the Viking LR experiments detected extant microbial life on Mars.

Assessments published in December 2010 by Rafael Navarro-Gonzles[186][187][188][189] indicate that organic compounds "could have been present" in the soil analyzed by both Viking 1 and 2. The study determined that perchloratediscovered in 2008 by Phoenix lander[190][191]can destroy organic compounds when heated, and produce chloromethane and dichloromethane as a byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars. Because perchlorate would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open.[192][193]

The Labeled Release evidence was not generally accepted initially, and, to this day lacks the consensus of the scientific community.[194]

As of 2018, there are 224 known Martian meteorites (some of which were found in several fragments).[195] These are valuable because they are the only physical samples of Mars available to Earth-bound laboratories. Some researchers have argued that microscopic morphological features found in ALH84001 are biomorphs, however this interpretation has been highly controversial and is not supported by the majority of researchers in the field.[196]

Seven criteria have been established for the recognition of past life within terrestrial geologic samples. Those criteria are:[196]

For general acceptance of past life in a geologic sample, essentially most or all of these criteria must be met. All seven criteria have not yet been met for any of the Martian samples.[196]

In 1996, the Martian meteorite ALH84001, a specimen that is much older than the majority of Martian meteorites that have been recovered so far, received considerable attention when a group of NASA scientists led by David S. McKay reported microscopic features and geochemical anomalies that they considered to be best explained by the rock having hosted Martian bacteria in the distant past. Some of these features resembled terrestrial bacteria, aside from their being much smaller than any known form of life. Much controversy arose over this claim, and ultimately all of the evidence McKay's team cited as evidence of life was found to be explainable by non-biological processes. Although the scientific community has largely rejected the claim ALH 84001 contains evidence of ancient Martian life, the controversy associated with it is now seen as a historically significant moment in the development of exobiology.[197][198]

The Nakhla meteorite fell on Earth on June 28, 1911, on the locality of Nakhla, Alexandria, Egypt.[199][200]

In 1998, a team from NASA's Johnson Space Center obtained a small sample for analysis. Researchers found preterrestrial aqueous alteration phases and objects[201] of the size and shape consistent with Earthly fossilized nanobacteria.Analysis with gas chromatography and mass spectrometry (GC-MS) studied its high molecular weight polycyclic aromatic hydrocarbons in 2000, and NASA scientists concluded that as much as 75% of the organic compounds in Nakhla "may not be recent terrestrial contamination".[196][202]

This caused additional interest in this meteorite, so in 2006, NASA managed to obtain an additional and larger sample from the London Natural History Museum. On this second sample, a large dendritic carbon content was observed. When the results and evidence were published in 2006, some independent researchers claimed that the carbon deposits are of biologic origin. It was remarked that since carbon is the fourth most abundant element in the Universe, finding it in curious patterns is not indicative or suggestive of biological origin.[203][204]

The Shergotty meteorite, a 4 kilograms (8.8lb) Martian meteorite, fell on Earth on Shergotty, India on August 25, 1865, and was retrieved by witnesses almost immediately.[205] It is composed mostly of pyroxene and thought to have undergone preterrestrial aqueous alteration for several centuries. Certain features in its interior suggest remnants of a biofilm and its associated microbial communities.[196]

Yamato 000593 is the second largest meteorite from Mars found on Earth. Studies suggest the Martian meteorite was formed about 1.3billion years ago from a lava flow on Mars. An impact occurred on Mars about 12million years ago and ejected the meteorite from the Martian surface into space. The meteorite landed on Earth in Antarctica about 50,000 years ago. The mass of the meteorite is 13.7kg (30lb) and it has been found to contain evidence of past water movement.[206][207][208] At a microscopic level, spheres are found in the meteorite that are rich in carbon compared to surrounding areas that lack such spheres. The carbon-rich spheres may have been formed by biotic activity according to NASA scientists.[206][207][208]

Organismsubstrate interactions and their products are important biosignatures on Earth as they represent direct evidence of biological behaviour.[209] It was the recovery of fossilized products of life-substrate interactions (ichnofossils) that has revealed biological activities in the early history of life on the Earth,e.g., Proterozoic burrows, Archean microborings and stromatolites.[210][211][212][213][214][215] Two major ichnofossil-like structures have been reported from Mars, i.e. the stick-like structures from Vera Rubin Ridge and the microtunnels from Martian Meteorites.

Observations at Vera Rubin Ridge by the Mars Space Laboratory rover Curiosity show millimetric, elongate structures preserved in sedimentary rocks deposited in fluvio-lacustrine environments within Gale Crater. Morphometric and topologic data are unique to the stick-like structures among Martian geological features and show that ichnofossils are among the closest morphological analogues of these unique features.[216] Nevertheless, available data cannot fully disprove two major abiotic hypotheses, that are sedimentary cracking and evaporitic crystal growth as genetic processes for the structures.

Microtunnels have been described from Martian meteorites. They consist of straight to curved microtunnels that may contain areas of enhanced carbon abundance. The morphology of the curved microtunnels is consistent with biogenic traces on Earth, including microbioerosion traces observed in basaltic glasses.[217][218][215] Further studies are needed to confirm biogenicity.

Artist's concept showing sand-laden jets erupt from geysers on Mars.

Close up of dark dune spots, probably created by cold geyser-like eruptions.

The seasonal frosting and defrosting of the southern ice cap results in the formation of spider-like radial channels carved on 1-meter thick ice by sunlight. Then, sublimed CO2 and probably water increase pressure in their interior producing geyser-like eruptions of cold fluids often mixed with dark basaltic sand or mud.[219][220][221][222] This process is rapid, observed happening in the space of a few days, weeks or months, a growth rate rather unusual in geology especially for Mars.[223]

A team of Hungarian scientists propose that the geysers' most visible features, dark dune spots and spider channels, may be colonies of photosynthetic Martian microorganisms, which over-winter beneath the ice cap, and as the sunlight returns to the pole during early spring, light penetrates the ice, the microorganisms photosynthesize and heat their immediate surroundings. A pocket of liquid water, which would normally evaporate instantly in the thin Martian atmosphere, is trapped around them by the overlying ice. As this ice layer thins, the microorganisms show through grey. When the layer has completely melted, the microorganisms rapidly desiccate and turn black, surrounded by a grey aureole.[224][225][226] The Hungarian scientists believe that even a complex sublimation process is insufficient to explain the formation and evolution of the dark dune spots in space and time.[227][228] Since their discovery, fiction writer Arthur C. Clarke promoted these formations as deserving of study from an astrobiological perspective.[229]

A multinational European team suggests that if liquid water is present in the spiders' channels during their annual defrost cycle, they might provide a niche where certain microscopic life forms could have retreated and adapted while sheltered from solar radiation.[230] A British team also considers the possibility that organic matter, microbes, or even simple plants might co-exist with these inorganic formations, especially if the mechanism includes liquid water and a geothermal energy source.[223] They also remark that the majority of geological structures may be accounted for without invoking any organic "life on Mars" hypothesis.[223] It has been proposed to develop the Mars Geyser Hopper lander to study the geysers up close.[231]

Planetary protection of Mars aims to prevent biological contamination of the planet.[232] A major goal is to preserve the planetary record of natural processes by preventing human-caused microbial introductions, also called forward contamination. There is abundant evidence as to what can happen when organisms from regions on Earth that have been isolated from one another for significant periods of time are introduced into each other's environment. Species that are constrained in one environment can thrive often out of control in another environment much to the detriment of the original species that were present. In some ways, this problem could be compounded if life forms from one planet were introduced into the totally alien ecology of another world.[233]

The prime concern of hardware contaminating Mars derives from incomplete spacecraft sterilization of some hardy terrestrial bacteria (extremophiles) despite best efforts.[26][234] Hardware includes landers, crashed probes, end-of-mission disposal of hardware, and the hard landing of entry, descent, and landing systems. This has prompted research on survival rates of radiation-resistant microorganisms including the species Deinococcus radiodurans and genera Brevundimonas, Rhodococcus, and Pseudomonas under simulated Martian conditions.[235] Results from one of these experimental irradiation experiments, combined with previous radiation modeling, indicate that Brevundimonas sp. MV.7 emplaced only 30cm deep in Martian dust could survive the cosmic radiation for up to 100,000 years before suffering 106 population reduction.[235] The diurnal Mars-like cycles in temperature and relative humidity affected the viability of Deinococcus radiodurans cells quite severely.[236] In other simulations, Deinococcus radiodurans also failed to grow under low atmospheric pressure, under 0C, or in the absence of oxygen.[237]

Since the 1950s, researchers have used containers that simulate environmental conditions on Mars to determine the viability of a variety of lifeforms on Mars. Such devices, called "Mars jars" or "Mars simulation chambers", were first described and used in U.S. Air Force research in the 1950s by Hubertus Strughold, and popularized in civilian research by Joshua Lederberg and Carl Sagan.[238]

On April 26, 2012, scientists reported that an extremophile lichen survived and showed remarkable results on the adaptation capacity of photosynthetic activity within the simulation time of 34 days under Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR).[239][240][242][243][244] The ability to survive in an environment is not the same as the ability to thrive, reproduce, and evolve in that same environment, necessitating further study.[27][26]

Although numerous studies point to resistance to some of Mars conditions, they do so separately, and none has considered the full range of Martian surface conditions, including temperature, pressure, atmospheric composition, radiation, humidity, oxidizing regolith, and others, all at the same time and in combination.[245] Laboratory simulations show that whenever multiple lethal factors are combined, the survival rates plummet quickly.[27]

Astrobiologists funded by NASA are researching the limits of microbial life in solutions with high salt concentrations at low temperature.[246] Any body of liquid water under the polar ice caps or underground is likely to exist under high hydrostatic pressure and have a significant salt concentration. They know that the landing site of Phoenix lander, was found to be regolith cemented with water ice and salts, and the soil samples likely contained magnesium sulfate, magnesium perchlorate, sodium perchlorate, potassium perchlorate, sodium chloride and calcium carbonate.[246][247][248] Earth bacteria capable of growth and reproduction in the presence of highly salted solutions, called halophile or "salt-lover", were tested for survival using salts commonly found on Mars and at decreasing temperatures.[246] The species tested include Halomonas, Marinococcus, Nesterenkonia, and Virgibacillus.[246] Laboratory simulations show that whenever multiple Martian environmental factors are combined, the survival rates plummet quickly,[27] however, halophile bacteria were grown in a lab in water solutions containing more than 25% of salts common on Mars, and starting in 2019, the experiments will incorporate exposure to low temperature, salts, and high pressure.[246]

Mars-1 was the first spacecraft launched to Mars in 1962,[249] but communication was lost while en route to Mars. With Mars-2 and Mars-3 in 19711972, information was obtained on the nature of the surface rocks and altitude profiles of the surface density of the soil, its thermal conductivity, and thermal anomalies detected on the surface of Mars. The program found that its northern polar cap has a temperature below 110C (166F) and that the water vapor content in the atmosphere of Mars is five thousand times less than on Earth. No signs of life were found.[250]

Mariner Crater, as seen by Mariner 4 in 1965. Pictures like this suggested that Mars is too dry for any kind of life.

Mariner 4 probe performed the first successful flyby of the planet Mars, returning the first pictures of the Martian surface in 1965. The photographs showed an arid Mars without rivers, oceans, or any signs of life. Further, it revealed that the surface (at least the parts that it photographed) was covered in craters, indicating a lack of plate tectonics and weathering of any kind for the last 4billion years. The probe also found that Mars has no global magnetic field that would protect the planet from potentially life-threatening cosmic rays. The probe was able to calculate the atmospheric pressure on the planet to be about 0.6 kPa (compared to Earth's 101.3 kPa), meaning that liquid water could not exist on the planet's surface.[22] After Mariner 4, the search for life on Mars changed to a search for bacteria-like living organisms rather than for multicellular organisms, as the environment was clearly too harsh for these.[22][251][252]

Liquid water is necessary for known life and metabolism, so if water was present on Mars, the chances of it having supported life may have been determinant. The Viking orbiters found evidence of possible river valleys in many areas, erosion and, in the southern hemisphere, branched streams.[253][254][255]

The primary mission of the Viking probes of the mid-1970s was to carry out experiments designed to detect microorganisms in Martian soil because the favorable conditions for the evolution of multicellular organisms ceased some four billion years ago on Mars.[256] The tests were formulated to look for microbial life similar to that found on Earth. Of the four experiments, only the Labeled Release (LR) experiment returned a positive result,[dubious discuss] showing increased 14CO2 production on first exposure of soil to water and nutrients. All scientists agree on two points from the Viking missions: that radiolabeled 14CO2 was evolved in the Labeled Release experiment, and that the GCMS detected no organic molecules. There are vastly different interpretations of what those results imply: A 2011 astrobiology textbook notes that the GCMS was the decisive factor due to which "For most of the Viking scientists, the final conclusion was that the Viking missions failed to detect life in the Martian soil."[257]

Norman Horowitz was the head of the Jet Propulsion Laboratory bioscience section for the Mariner and Viking missions from 1965 to 1976. Horowitz considered that the great versatility of the carbon atom makes it the element most likely to provide solutions, even exotic solutions, to the problems of survival of life on other planets.[258] However, he also considered that the conditions found on Mars were incompatible with carbon based life.

One of the designers of the Labeled Release experiment, Gilbert Levin, believes his results are a definitive diagnostic for life on Mars.[22] Levin's interpretation is disputed by many scientists.[259] A 2006 astrobiology textbook noted that "With unsterilized Terrestrial samples, though, the addition of more nutrients after the initial incubation would then produce still more radioactive gas as the dormant bacteria sprang into action to consume the new dose of food. This was not true of the Martian soil; on Mars, the second and third nutrient injections did not produce any further release of labeled gas."[260] Other scientists argue that superoxides in the soil could have produced this effect without life being present.[261] An almost general consensus discarded the Labeled Release data as evidence of life, because the gas chromatograph and mass spectrometer, designed to identify natural organic matter, did not detect organic molecules.[181] More recently, high levels of organic chemicals, particularly chlorobenzene, were detected in powder drilled from one of the rocks, named "Cumberland", analyzed by the Curiosity rover.[262][263] The results of the Viking mission concerning life are considered by the general expert community as inconclusive.[22][261][264]

In 2007, during a Seminar of the Geophysical Laboratory of the Carnegie Institution (Washington, D.C., US), Gilbert Levin's investigation was assessed once more.[181] Levin still maintains that his original data were correct, as the positive and negative control experiments were in order.[185] Moreover, Levin's team, on April 12, 2012, reported a statistical speculation, based on old datareinterpreted mathematically through cluster analysisof the Labeled Release experiments, that may suggest evidence of "extant microbial life on Mars".[185][265] Critics counter that the method has not yet been proven effective for differentiating between biological and non-biological processes on Earth so it is premature to draw any conclusions.[266]

A research team from the National Autonomous University of Mexico headed by Rafael Navarro-Gonzlez concluded that the GCMS equipment (TV-GC-MS) used by the Viking program to search for organic molecules, may not be sensitive enough to detect low levels of organics.[189] Klaus Biemann, the principal investigator of the GCMS experiment on Viking wrote a rebuttal.[267] Because of the simplicity of sample handling, TVGCMS is still considered the standard method for organic detection on future Mars missions, so Navarro-Gonzlez suggests that the design of future organic instruments for Mars should include other methods of detection.[189]

After the discovery of perchlorates on Mars by the Phoenix lander, practically the same team of Navarro-Gonzlez published a paper arguing that the Viking GCMS results were compromised by the presence of perchlorates.[268] A 2011 astrobiology textbook notes that "while perchlorate is too poor an oxidizer to reproduce the LR results (under the conditions of that experiment perchlorate does not oxidize organics), it does oxidize, and thus destroy, organics at the higher temperatures used in the Viking GCMS experiment."[269] Biemann has written a commentary critical of this Navarro-Gonzlez paper as well,[270] to which the latter have replied;[271] the exchange was published in December 2011.

The Phoenix mission landed a robotic spacecraft in the polar region of Mars on May 25, 2008, and it operated until November 10, 2008. One of the mission's two primary objectives was to search for a "habitable zone" in the Martian regolith where microbial life could exist, the other main goal being to study the geological history of water on Mars. The lander has a 2.5 meter robotic arm that was capable of digging shallow trenches in the regolith. There was an electrochemistry experiment which analysed the ions in the regolith and the amount and type of antioxidants on Mars. The Viking program data indicate that oxidants on Mars may vary with latitude, noting that Viking 2 saw fewer oxidants than Viking 1 in its more northerly position. Phoenix landed further north still.[272]Phoenix's preliminary data revealed that Mars soil contains perchlorate, and thus may not be as life-friendly as thought earlier.[273][274][191] The pH and salinity level were viewed as benign from the standpoint of biology. The analysers also indicated the presence of bound water and CO2.[275] A recent analysis of Martian meteorite EETA79001 found 0.6 ppm ClO4, 1.4 ppm ClO3, and 16 ppm NO3, most likely of Martian origin. The ClO3 suggests presence of other highly oxidizing oxychlorines such as ClO2 or ClO, produced both by UV oxidation of Cl and X-ray radiolysis of ClO4. Thus only highly refractory and/or well-protected (sub-surface) organics are likely to survive.[276] In addition, recent analysis of the Phoenix WCL showed that the Ca(ClO4)2 in the Phoenix soil has not interacted with liquid water of any form, perhaps for as long as 600 Myr. If it had, the highly soluble Ca(ClO4)2 in contact with liquid water would have formed only CaSO4. This suggests a severely arid environment, with minimal or no liquid water interaction.[277]

The Mars Science Laboratory mission is a NASA project that launched on November 26, 2011, the Curiosity rover, a nuclear-powered robotic vehicle, bearing instruments designed to assess past and present habitability conditions on Mars.[278][279] The Curiosity rover landed on Mars on Aeolis Palus in Gale Crater, near Aeolis Mons (a.k.a. Mount Sharp),[280][281][282][283] on August 6, 2012.[284][285][286]

On December 16, 2014, NASA reported the Curiosity rover detected a "tenfold spike", likely localized, in the amount of methane in the Martian atmosphere. Sample measurements taken "a dozen times over 20 months" showed increases in late 2013 and early 2014, averaging "7 parts of methane per billion in the atmosphere". Before and after that, readings averaged around one-tenth that level.[262][263] In addition, low levels of chlorobenzene (C6H5Cl), were detected in powder drilled from one of the rocks, named "Cumberland", analyzed by the Curiosity rover.[262][263]

The Mars 2020 rover is a Mars planetary rover mission by NASA, launched on 30 July 2020. It is intended to investigate an astrobiologically relevant ancient environment on Mars, investigate its surface geological processes and history, including the assessment of its past habitability and potential for preservation of biosignatures within accessible geological materials.[288]

Some of the main reasons for colonizing Mars include economic interests, long-term scientific research best carried out by humans as opposed to robotic probes, and sheer curiosity. Surface conditions and the presence of water on Mars make it arguably the most hospitable of the planets in the Solar System, other than Earth. Human colonization of Mars would require in situ resource utilization (ISRU); A NASA report states that "applicable frontier technologies include robotics, machine intelligence, nanotechnology, synthetic biology, 3-D printing/additive manufacturing, and autonomy. These technologies combined with the vast natural resources should enable, pre- and post-human arrival ISRU to greatly increase reliability and safety and reduce cost for human colonization of Mars."[291][292][293]

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Life on Mars - Wikipedia