Mars to Stay

From Wikipedia, the free encyclopedia

Concept for NASA Design Reference Mission Architecture 5.0 (2009)

Mars to Stay missions propose astronauts sent to Mars for the first time should intend to stay. Unused emergency return vehicles would be recycled into settlement construction as soon as the habitability of Mars becomes evident to the initial pioneers. Mars to Stay missions are advocated both to reduce cost and to ensure permanent settlement of Mars. Among many notable Mars to Stay advocates, former Apollo astronaut Buzz Aldrin has been particularly outspoken, suggesting in numerous forums "Forget the Moon, Let’s Head to Mars!"^[1] and, in June 2013, Aldrin promoted a manned mission "to homestead Mars and become a two-planet species".^[2] In August 2015, Aldrin, in association with the Florida Institute of Technology, presented a "master plan", for NASA consideration, for astronauts, with a "tour of duty of ten years", to colonize Mars before the year 2040.^[3] The Mars Underground, Mars Homestead Foundation, Mars One, and Mars Artists Community advocacy groups and business organizations have also adopted Mars to Stay policy initiatives.^[4]

The earliest formal outline of a Mars to Stay mission architecture was given at the Case for Mars VI Workshop in 1996, during a presentation by George Herbert titled "One Way to Mars".^[5]

Proposals

Arguments for settlement missions

Since returning the astronauts from the surface of Mars is one of the most difficult parts of a Mars mission, the idea of a one-way trip to Mars has been proposed several times. Space activist Bruce Mackenzie, for example, proposed a one-way trip to Mars in a presentation "One Way to Mars – a Permanent Settlement on the First Mission" at the 1998 International Space Development Conference,^[6] arguing that since the mission could be done with less difficulty and expense if the astronauts were not required to return to Earth, the first mission to Mars should be a settlement, not a visit.

Paul Davies, writing in the New York Times in 2004, made similar arguments.^[7] Under Davies' plan, an initial colony of four astronauts equipped with a small nuclear reactor and a couple of rover vehicles would make their own oxygen, grow food, and even initiate building projects using local raw materials. Supplemented by food shipments, medical supplies, and replacement gadgets from Earth, the colony would be indefinitely sustained.

Original Aldrin plan

Under Mars to Stay mission architectures, the first humans to travel to Mars would typically be in six-member teams. After this initial landing, subsequent missions would raise the number of persons on Mars to 30, thereby beginning a Martian settlement. Since the Martian surface offers all the natural resources and elements necessary to sustain a robust, mature, industrialized human settlement^[8]—unlike, for example the Moon^[9]—a permanent Martian settlement is thought to be the most effective way to ensure that humanity becomes a space-faring, multi-planet species.^[10] Through the use of digital fabricators and in vitro fertilisation it is assumed a permanent human settlement on Mars can grow organically from an original thirty to forty pioneers.^[11]

A Mars to Stay mission following Aldrin's proposal would enlist astronauts in the following timeline:

• Age 30: an offer to help settle Mars is extended to select pioneers
• Age 30–35: training and social conditioning for long-duration isolation and time-delay communications
• Age 35: launch three married couples to Mars; followed in subsequent years by a dozen or more couples
• Age 35–65: development of sheltered underground living spaces; artificial insemination ensures genetic diversity
• Age 65: an offer to return to Earth or retire on Mars is given to first-generation settlers

As Aldrin has said, "who knows what advances will have taken place. The first generation can retire there, or maybe we can bring them back."^[11]

"To Boldly Go: A One-Way Human Mission to Mars"

An article by Dirk Schulze-Makuch (Washington State University) and Paul Davies (Arizona State University) from the book The Human Mission to Mars: Colonizing the Red Planet^[12] highlights their mission plans as:

• No base on the Moon is needed. Given the broad variety of resources available on Mars, the long-term survival of Martian settlers is much more feasible than Lunar settlers.
• Since Mars affords neither an ozone shield nor magnetospheric protection, robots would prepare a basic modular base inside near-surface lava tubes and ice caves for the human settlers.
• A volunteer signing up for a one-way mission to Mars would do so with the full understanding that they will not return to Earth; Mars exploration would proceed for a long time on the basis of outbound journeys only.
• The first human contingent would consist of a crew of four, ideally (if budget permits) distributed between two two-man spacecraft for mission redundancy.
• Over time humans on Mars will increase with follow-up missions. Several subsurface biospheres would be created until there were 150+ individuals in a viable gene pool. Genetic engineering would further contribute to the health and longevity of settlers.

The astronauts would be sent supplies from Earth regularly. This proposal was picked up for discussion in a number of public sources.^[13]

Mars One

A proposal for a one-way human settlement mission to Mars was put forward in 2012 by the Mars One, a private spaceflight project led by Dutch entrepreneur Bas Lansdorp to establish a permanent human colony on Mars.^[14] Mars One is a Dutch not-for-profit foundation, a Stichting.^[15][16] The proposal is to send a communication satellite and path finder lander to the planet by 2018 and, after several stages, land four humans on Mars for permanent settlement in 2027.^[17] A new set of four astronauts would then arrive every two years.^[18] 200,000 applications were started; about 2,500 were complete enough for consideration, from which one hundred applicants have been chosen so far. Further selections are planned to narrow this down to six groups of four before training begins in 2016.^{[19][needs update]} It is hoped their reality television show, participant fees, and donations will generate the funding for the project.^[20]

The project has been criticized by experts as a 'scam'^{[21][22][23][24][25]} and as 'delusional'.^{[26][27][20][28]}

Strive to Stay: Emergency Return Only

In response to feedback following the EarthLight Institute's "Mars Colony 2030" project at NewSpace 2012 and the announcement of Mars One, Eric Machmer proposed conjunction-class missions be planned with a bias to stay (if low gravity, radiation, and other factors present no pressing health issues),^[29][30] so that, if at the end of each 550-day period during a conjunction-class launch window no adverse health effects were observed, settlers would continue research and construction through another 550-day period. In the meantime, additional crews and supplies would continue to arrive, starting their own 550-day evaluation periods. Health tests would be repeated during subsequent 550-day periods until the viability of human life on Mars was proven. Once settlers determine that humans can live on Mars without negative health effects, emergency return vehicles would be recycled into permanent research bases.

Initial and permanent settlement

Initial explorers leave equipment in orbit and at landing zones scattered considerable distances from the main settlement. Subsequent missions therefore are assumed to become easier and safer to undertake, with the likelihood of back-up equipment being present if accidents in transit or landing occur.

Large subsurface, pressurized habitats would be the first step toward human settlement; as Dr. Robert Zubrin suggests in the first chapter of his book Mars Direct, these structures can be built as Roman-style atria in mountainsides or underground with easily produced Martian brick. During and after this initial phase of habitat construction, hard-plastic radiation and abrasion-resistant geodesic domes could be deployed on the surface for eventual habitation and crop growth. Nascent industry would begin using indigenous resources: the manufacture of plastics, ceramics and glass could be easily achieved.

The longer-term work of terraforming Mars requires an initial phase of global warming to release atmosphere from the Martian regolith and to create a water-cycle. Three methods of global warming are described by Zubrin, who suggests they are best deployed in tandem: orbital mirrors to heat the surface; factories on the ground to pump halocarbons into the atmosphere; and the seeding of bacteria that can metabolize water, nitrogen and carbon to produce ammonia and methane (these gases would aid in global warming). While the work of terraforming Mars is on-going, robust settlement of Mars would continue.

Zubrin, in his 1996 book (revised 2011) The Case for Mars, acknowledges any Martian colony will be partially Earth-dependent for centuries. However, Zubrin suggests Mars may be profitable for two reasons. First, it may contain concentrated supplies of metals equal to or of greater value than silver, which have not been subjected to millennia of human scavenging; it is suggested such ores may be sold on Earth for profit. Secondly, the concentration of deuterium—an extremely expensive but essential fuel for the as-yet non-existent nuclear fusion power industry—is five times greater on Mars. Humans emigrating to Mars, under this paradigm, are presumed to have an industry; it is assumed the planet will be a magnet for settlers as wage costs will be high. Because of the labor shortage on Mars and its subsequent high pay-scale, Martian civilization and the value placed upon each individual's productivity is proposed as a future engine of both technological and social advancement.

Risks

Artist's conception of a human mission on Mars
1989 painting by Les Bossinas of Lewis Research Center for NASA

In the fifth chapter of "Mars Direct", Zubrin addresses the idea that radiation and zero-gravity are unduly hazardous. He claims cancer rates do increase for astronauts who have spent extensive time in space, but only marginally. Similarly, while zero-gravity presents challenges, near total recovery of musculature and immune system vitality is presumed by all Mars to Stay mission plans once settlers are on the Martian surface. Several experiments, such as the Mars Gravity Biosatellite, have been proposed to test this hypothetical assumption, but until humans have lived in Martian gravity conditions (38% of Earth's), human long-term viability in such low gravity will remain only a working assumption. Back-contamination—humans acquiring and spreading hypothetical Martian viruses—is described as "just plain nuts", because there are no host organisms on Mars for disease organisms to have evolved.

In the same chapter, Zubrin rejects suggestions the Moon should be used as waypoint to Mars or as a preliminary training area. "It is ultimately much easier to journey to Mars from low Earth orbit than from the Moon and using the latter as a staging point is a pointless diversion of resources." While the Moon may superficially appear a good place to perfect Mars exploration and habitation techniques, the two bodies are radically different. The Moon has no atmosphere, no analogous geology and a much greater temperature range and rotational period of illumination. It is argued Antarctica, deserts of Earth, and precisely controlled chilled vacuum chambers on easily accessible NASA centers on Earth provide much better training grounds at lesser cost.

Public reception

Artist's conception of a Mars Habitat
1993 by John Frassanito and Associates for NASA

"Should the United States space program send a mission to Mars, those astronauts should be prepared to stay there," said Lunar astronaut Buzz Aldrin during an interview on "Mars to Stay" initiative.^[31] The time and expense required to send astronauts to Mars, argues Aldrin, "warrants more than a brief sojourn, so those who are on board should think of themselves as pioneers. Like the Pilgrims who came to the New World or the families who headed to the Wild West, they should not plan on coming back home." The Moon is a shorter trip of two or three days, but according to Mars advocates it offers virtually no potential for independent settlements. Studies have found that Mars, on the other hand, has vast reserves of frozen water, all of the basic elements, and more closely mimics both gravitational (roughly ​¹⁄₃ of Earth's while the moon is ​¹⁄₆) and illumination conditions on Earth. "It is easier to subsist, to provide the support needed for people there than on the Moon." In an interview with reporters, Aldrin said Mars offers greater potential than Earth's satellite as a place for habitation:

If we are going to put a few people down there and ensure their appropriate safety, would you then go through all that trouble and then bring them back immediately, after a year, a year and a half? ... They need to go there more with the psychology of knowing that you are a pioneering settler and you don't look forward to go back home again after a couple of years.^[32]

A comprehensive statement of a rationale for "Mars to Stay" was laid out by Dr. Aldrin in a May 2009 Popular Mechanics article, as follows:

The agency's current Vision for Space Exploration will waste decades and hundreds of billions of dollars trying to reach the Moon by 2020—a glorified rehash of what we did 40 years ago. Instead of a steppingstone to Mars, NASA's current lunar plan is a detour. It will derail our Mars effort, siphoning off money and engineering talent for the next two decades. If we aspire to a long-term human presence on Mars—and I believe that should be our overarching goal for the foreseeable future—we must drastically change our focus. Our purely exploratory efforts should aim higher than a place we've already set foot on six times. In recent years my philosophy on colonizing Mars has evolved. I now believe that human visitors to the Red Planet should commit to staying there permanently. One-way tickets to Mars will make the missions technically easier and less expensive and get us there sooner. More importantly, they will ensure that our Martian outpost steadily grows as more homesteaders arrive. Instead of explorers, one-way Mars travelers will be 21st-century pilgrims, pioneering a new way of life. It will take a special kind of person. Instead of the traditional pilot/scientist/engineer, Martian homesteaders will be selected more for their personalities—flexible, inventive and determined in the face of unpredictability. In short, survivors.^[33]

The Mars Artists Community has adopted Mars to Stay as their primary policy initiative.^[34] During a 2009 public hearing of the U.S. Human Space Flight Plans Committee at which Dr. Robert Zubrin presented a summary of the arguments in his book The Case for Mars, dozens of placards reading "Mars Direct Cowards Return to the Moon" were placed throughout the Carnegie Institute.^[35] The passionate uproar among space exploration advocates—both favorable and critical—resulted in the Mars Artists Community creating several dozen more designs, with such slogans as, "Traitors Return to Earth" and "What Would Zheng He Do?"

Mars Artists design, August 2009.

In October 2009, Eric Berger of the Houston Chronicle wrote of "Mars to Stay" as perhaps the only program that can revitalize the United States' space program:

What if NASA could land astronauts on Mars in a decade, for not ridiculously more money than the $10 billion the agency spends annually on human spaceflight? It's possible ... relieving NASA of the need to send fuel and rocketry to blast humans off the Martian surface, which has slightly more than twice the gravity of the moon, would actually reduce costs by about a factor of 10, by some estimates.^[36]

Hard Science Fiction writer Mike Brotherton has found "Mars to Stay" appealing for both economic and safety reasons, but more emphatically, as a fulfillment of the ultimate mandate by which "our manned space program is sold, at least philosophically and long-term, as a step to colonizing other worlds". Two-thirds of the respondents to a poll on his website expressed interest in a one-way ticket to Mars "if mission parameters are well-defined" (not suicidal).^[37]

In June 2010, Buzz Aldrin gave an interview to Vanity Fair in which he restated "Mars to Stay":

Did the Pilgrims on the Mayflower sit around Plymouth Rock waiting for a return trip? They came here to settle. And that's what we should be doing on Mars. When you go to Mars, you need to have made the decision that you're there permanently. The more people we have there, the more it can become a sustaining environment. Except for very rare exceptions, the people who go to Mars shouldn't be coming back. Once you get on the surface, you're there.^[38]

An article by Dirk Schulze-Makuch (Washington State University) and Paul Davies (Arizona State University) from the book The Human Mission to Mars: Colonizing the Red Planet^[12] summarizes their rationale for Mars to Stay:

[Mars to stay] would obviate the need for years of rehabilitation for returning astronauts, which would not be an issue if the astronauts were to remain in the low-gravity environment of Mars. We envision that Mars exploration would begin and proceed for a long time on the basis of outbound journeys only.^[12]

In November 2010, Keith Olbermann started an interview with Derrick Pitts, Planetarium Director at the Franklin Institute in Philadelphia, by quoting from the Dirk Schulze-Makuch and Paul Davies article, saying, "The Astronauts would go to Mars with the intention of staying for the rest of their lives, as trailblazers of a permanent human Mars colony." In response to Olbermann's statement that "the authors claim a one-way ticket to Mars is no more outlandish than a one-way ticket to America was in 1620", Pitts defends Mars to Stay initiatives by saying "they begin to open the doors in a way that haven't been opened before".^[39]

In a January 2011 interview, X Prize founder Peter Diamandis expressed his preference for Mars to Stay research settlements:

Privately funded missions are the only way to go to Mars with humans because I think the best way to go is on "one-way" colonization flights and no government will likely sanction such a risk. The timing for this could well be within the next 20 years. It will fall within the hands of a small group of tech billionaires who view such missions as the way to leave their mark on humanity.^[40]

In March 2011, Apollo 14 pilot Edgar Mitchell and Apollo 17's geologist Harrison Schmitt, among other noted Mars exploration advocates published an anthology of Mars to Stay architectures titled, A One Way Mission to Mars: Colonizing the Red Planet". From the publisher's review:

Answers are provided by a veritable who's who of the top experts in the world. And what would it be like to live on Mars? What dangers would they face? Learn first hand, in the final, visionary chapter about life in a Martian colony, and the adventures of a young woman, Aurora, who is born on Mars. Exploration, discovery, and journeys into the unknown are part of the human spirit. Colonizing the cosmos is our destiny. The Greatest Adventure in the History of Humanity awaits us. Onward to Mars!^[41]

August 2011, Professor Paul Davies gave a plenary address to the opening session of the 14th Annual International Mars Society Convention on cost-effective human mission plans for Mars titled "One-Way Mission to Mars".^[42]

New York Times op-eds

"Mars to Stay" has been explicitly proposed by two op-ed pieces in the New York Times.^[7][43]

Following a similar line of argument to Buzz Aldrin, Lawrence Krauss asks in an op-ed, "Why are we so interested in bringing the Mars astronauts home again?".^[43] While the idea of sending astronauts aloft never to return may be jarring upon first hearing, the rationale for one-way exploration and settlement trips has both historical and practical roots. For example, colonists and pilgrims seldom set off to the New World with the expectation of a return trip. As Lawrence Krauss writes, "To boldly go where no one has gone before does not require coming home again."

If it sounds unrealistic to suggest that astronauts would be willing to leave home never to return ... consider the results of several informal surveys I and several colleagues have conducted recently. One of my peers in Arizona recently accompanied a group of scientists and engineers from the Jet Propulsion Laboratory on a geological survey. He asked how many would be willing to go on a one-way mission into space. Every member of the group raised their hand.^[43]

Additional immediate and pragmatic reasons to consider one-way human space exploration missions are explored by Krauss. Since much of the cost of a voyage to Mars will be spent on returning to Earth, if the fuel for the return is carried on board, this greatly increases the mission mass requirement – that in turn requires even more fuel. According to Krauss, "Human space travel is so expensive and so dangerous ... we are going to need novel, even extreme solutions if we really want to expand the range of human civilization beyond our own planet." Delivering food and supplies to pioneers via unmanned spacecraft is less expensive than designing an immediate return trip.

In an earlier 2004 op-ed for the New York Times, Paul Davies says motivation for the less expensive, permanent "one-way to stay option" arises from a theme common in "Mars to Stay" advocacy: "Mars is one of the few accessible places beyond Earth that could have sustained life [... and] alone among our sister planets, it is able to support a permanent human presence."^[7]

Why is going to Mars so expensive? ... It takes a lot of fuel to blast off Mars and get back home. If the propellant has to be transported there from Earth, costs of a launching soar.
Without some radical improvements in technology, the prospects for sending astronauts on a round-trip to Mars any time soon are slim, whatever the presidential rhetoric. What's more, the president's suggestion of using the Moon as a base — a place to assemble equipment and produce fuel for a Mars mission less expensively — has the potential to turn into a costly sideshow. There is, however, an obvious way to slash the costs and bring Mars within reach of early manned exploration. The answer lies with a one-way mission.^[7]

Davies argues that since "some people gleefully dice with death in the name of sport or adventure [and since] dangerous occupations that reduce life expectancy through exposure to hazardous conditions or substances are commonplace", we ought to not find the risks involved in a Mars to Stay architecture unusual. "A century ago, explorers set out to trek across Antarctica in the full knowledge that they could die in the process, and that even if they succeeded their health^[29] might be irreversibly harmed. Yet governments and scientific societies were willing sponsors of these enterprises." Davies then asks, "Why should it be different today?"^[7]

In situ resource utilization

From Wikipedia, the free encyclopedia

ISRU reverse water gas shift testbed (NASA KSC)

In space exploration, in situ resource utilization (ISRU) is defined as "the collection, processing, storing and use of materials encountered in the course of human or robotic space exploration that replace materials that would otherwise be brought from Earth."^[1] ISRU is the practice of leveraging resources found or manufactured on other astronomical objects (the Moon, Mars, asteroids, etc.) to fulfill or enhance the requirements and capabilities of a space mission.

ISRU can provide materials for life support, propellants, construction materials, and energy to a spacecraft payloads or space exploration crews. It is now very common for spacecraft and robotic planetary surface mission to harness the solar radiation found in situ in the form of solar panels. The use of ISRU for material production has not yet been implemented in a space mission, though several field tests in the late 2000s demonstrated various lunar ISRU techniques in a relevant environment.^[2]

ISRU has long been considered as a possible avenue for reducing the mass and cost of space exploration architectures, in that it may be a way to drastically reduce the amount of payload that must be launched from Earth in order to explore a given planetary body. According to NASA, "in-situ resource utilisation will enable the affordable establishment of extraterrestrial exploration and operations by minimizing the materials carried from Earth."^[3]

Uses

Water

In the context of ISRU water is most often sought directly as fuel or as feedstock for fuel production. Applications include its use in life support either directly by drinking, for growing food, producing oxygen, or numerous other industrial processes. All of which require a ready supply of water in the environment and the equipment to extract it. Such extraterrestrial water has been discovered in a variety of forms throughout the solar system, and a number of potential water extraction technologies have been investigated. For water that is chemically bound to regolith, solid ice, or some manner of permafrost, sufficient heating can recover the water. However this is not as easy as it appears because ice and permafrost can often be harder than plain rock, necessitating laborious mining operations. Where there is some level of atmosphere, such as on Mars, water can be extracted directly from the air using a simple process such as WAVAR. Another possible source of water is deep aquifers kept warm by Mars's latent geological heat, which can be tapped to provide both water and geothermal power.

Rocket propellant

Rocket propellant from water ice has also been proposed for the Moon, mainly from ice that has been found at the poles. The likely difficulties include working at extremely low temperatures and extraction from the regolith. Most schemes electrolyse the water and form hydrogen and oxygen and liquify and cryogenically store them. This requires large amounts of equipment and power to achieve. Alternatively it is possible to simply heat the water in a nuclear or solar thermal rocket,^[4] which seems to give very much more mass delivered to low Earth orbit (LEO) in spite of the much lower specific impulse, for a given amount of equipment.^[5]

The monopropellant hydrogen peroxide (H₂O₂) can be made from water on Mars and the Moon.^[6]

Aluminum as well as other metals have been proposed for use as rocket propellant made using lunar resources,^[7] and proposals include reacting the aluminum with water.^[8] For Mars, methane propellant can be manufactured via the Sabatier process.

Solar cell production

It has long been suggested that solar cells could be produced from the materials present in lunar soil. Silicon, aluminium, and glass, three of the primary materials required for solar cell production, are found in high concentrations in lunar soil and can be utilised to produce solar cells.^[9] In fact, the native vacuum on the lunar surface provides an excellent environment for direct vacuum deposition of thin-film materials for solar cells.^[10]

Solar arrays produced on the lunar surface can be used to support lunar surface operations as well as satellites off the lunar surface. Solar arrays produced on the lunar surface may prove more cost effective than solar arrays produced and shipped from Earth, but this trade depends heavily on the location of the particular application in question.

Another potential application of lunar-derived solar arrays is providing power to Earth. In its original form, known as the solar power satellite, the proposal was intended as an alternate power source for Earth. Solar cells would be shipped to Earth orbit and assembled, the power being transmitted to Earth via microwave beams.^[11] Despite much work on the cost of such a venture, the uncertainty lay in the cost and complexity of fabrication procedures on the lunar surface.

Metals for construction or return to Earth

Asteroid mining could also involve extraction of metals for construction material in space, which may be more cost-effective than bringing such material up out of Earth's deep gravity well, or that of any other large body like the Moon or Mars. Metallic asteroids contain huge amounts of siderophilic metals, including precious metals.

Building materials

The colonisation of planets or moons will require to obtain local building materials, such as regolith. For example, studies employing artificial Mars soil mixed with epoxy resin and tetraethoxysilane, produce high enough values of strength, resistance, and flexibility parameters.^[12]

Locations

Mars

ISRU research for Mars is focused primarily on providing rocket propellant for a return trip to Earth — either for a manned or a sample return mission — or for use as fuel on Mars. Many of the proposed techniques utilise the well-characterised atmosphere of Mars as feedstock. Since this can be easily simulated on Earth, these proposals are relatively simple to implement, though it is by no means certain that NASA or the ESA will favour this approach over a more conventional direct mission.^[13]

A typical proposal for ISRU is the use of a Sabatier reaction, CO₂ + 4H₂ → CH₄ + 2H₂O, in order to produce methane on the Martian surface, to be used as a propellant. Oxygen is liberated from the water by electrolysis, and the hydrogen recycled back into the Sabatier reaction. The usefulness of this reaction is that—as of 2008, when the availability of water on Mars was less scientifically demonstrated—only the hydrogen (which is light) was thought to need to be brought from Earth.^[14]

As of 2016, SpaceX is currently developing the technology for a Mars propellant plant that will use a variation on what is described in the previous paragraph. Rather than transporting hydrogen from Earth to use in making the methane and oxygen, they intend to mine the requisite water from subsurface water ice that is now known to be abundant across much of the Martian surface, produce and then store the post-Sabatier reactants, and then use it as propellant for return flights of their Interplanetary Spaceship no earlier than 2023.^[15][16]

A similar reaction proposed for Mars is the reverse water gas shift reaction, CO₂ + H₂ → CO + H₂O. This reaction takes place rapidly in the presence of an iron-chrome catalyst at 400 Celsius,^[17] and has been implemented in an Earth-based testbed by NASA.^[18] Again, oxygen is recycled from the water by electrolysis, and the reaction only needs a small amount of hydrogen from Earth. The net result of this reaction is the production of oxygen, to be used as the oxidizer component of rocket fuel.

Another reaction proposed for the production of oxygen and fuel^[19] is the electrolysis of the atmospheric carbon dioxide,

${\displaystyle {\ce {{\overset {atmospheric \atop {carbon\ dioxide}}{2CO2}}->[energy]{2CO}+O2}}}$.^[20]

More recently, it has been proposed the in situ production of oxygen, hydrogen and CO from the martian hematite deposits via a two-step thermochemical CO₂/H₂O splitting process, and specifically in the magnetite/wustite redox cycle.^[21] Although thermolysis is the most direct, one-step process for splitting molecules, it is neither practical nor efficient in the case of either H₂O or CO₂. This is because the process requires a very high temperature (> 2500 C) to achieve a meaningful dissociation fraction.^[22] This poses problems in finding suitable reactor materials, losses due to vigorous product recombination, and excessive aperture radiation losses when concentrated solar heat is used. The magnetite/wustite redox cycle was first proposed for solar application on earth by Nakamura,^[23] and was one of the first used for solar-driven two-step water splitting. In this cycle, water reacts with wustite (FeO) to form magnetite (Fe₃O₄) and hydrogen. The summarised reactions in this two-step splitting process are as follows:

${\displaystyle {\ce {Fe3O4->[energy]{3FeO}+\overbrace {1/2O2} ^{\underset {(\operatorname {by-product} )}{oxygen}}}}}$.

and the obtained FeO is used for the thermal splitting of water or CO₂ :

3FeO + H₂O → Fe₃O₄ + H₂

3FeO + CO₂ → Fe₃O₄ + CO

This process is repeated cyclically. The above process results in a substantial reduction in the thermal input of energy if compared with the most direct, one-step process for splitting molecules.^[24]

However, the process needs wustite (Fe₃O₄) to start the cycle, but on Mars there is no wustite or at least not in significant amounts. Nevertheless, wustite can be easily obtained by reduction of hematite (Fe₂O₃) which is an abundant material on Mars, being specially conspicuous the strong hematite deposits located at Terra Meridiani.^[25] The intention of wustite from the hematite -abundantly available on Mars, is an industrial process well-known on earth, and us performed by the following two main reduction reactions, namely:

3Fe₂O₃ + H₂ → 2Fe₃O₄ + H₂O

3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂

Mars Surveyor 2001 Lander MIP (Mars ISPP Precursor) was to demonstrate manufacture of oxygen from the atmosphere of Mars,^[26] and test solar cell technologies and methods of mitigating the effect of Martian dust on the power systems.^[27] The proposed Mars 2020 rover mission might include ISRU technology demonstrator that would extract CO₂ from the atmosphere and produce O₂ for rocket fuel.^[28]

It has been suggested that buildings on Mars could be made from basalt as it has good insulating properties. An underground structure of this type would be able to protect life forms against radiation exposure.^[29]

All of the resources required to make plastics exist on Mars.^[30][31] Many of these complex reactions are able to be completed from the gases harvested from the martian atmosphere. Traces of free oxygen, carbon monoxide, water and methane are all known to exist.^[32][33] Hydrogen and oxygen can be made by the electrolysis of water, carbon monoxide and oxygen by the electrolysis of carbon dioxide and methane by the Sabatier reaction of carbon dioxide and hydrogen. These basic reactions provide the building blocks for more complex reaction series which are able to make plastics.  Ethylene is used to make plastics such as polyethylene and polypropylene and can be made from carbon monoxide and hydrogen,^[34]

2CO + 4H₂ → C₂H₄ + 2H₂O.

Moon

Footprint in lunar regolith.

The Moon possesses abundant raw materials that are potentially relevant to a hierarchy of future applications, beginning with the use of lunar materials to facilitate human activities on the Moon itself and progressing to the use of lunar resources to underpin a future industrial capability within the Earth-Moon system.^[35]

The lunar highland material anorthite can be used as aluminium ore. Smelters can produce pure aluminium, calcium metal, oxygen and silica glass from anorthite. Raw anorthite is also good for making fiberglass and other glass and ceramic products.^[36] One particular processing technique is to use fluorine brought from Earth as potassium fluoride to separate the raw materials from the lunar rocks.^[37]

Over twenty different methods have been proposed for oxygen extraction on the Moon.^[7] Oxygen is often found in iron rich lunar minerals and glasses as iron oxide. The oxygen can be extracted by heating the material to temperatures above 900 °C and exposing it to hydrogen gas. The basic equation is: FeO + H₂ → Fe + H₂O. This process has recently been made much more practical by the discovery of significant amounts of hydrogen-containing regolith near the Moon's poles by the Clementine spacecraft.^[38]

Lunar materials may also be valuable for other uses. It has also been proposed to use lunar regolith as a general construction material,^[39] through processing techniques such as sintering, hot-pressing, liquification, and the cast basalt method. Cast basalt is used on Earth for construction of, for example, pipes where a high resistance to abrasion is required. Cast basalt has a very high hardness of 8 Mohs (diamond is 10 Mohs) but is also susceptible to mechanical impact and thermal shock^[40] which could be a problem on the Moon.

Glass and glass fiber are straightforward to process on the Moon and Mars, and it has been argued that the glass is optically superior to that made on the Earth because it can be made anhydrous.^[36] Successful tests have been performed on Earth using two lunar regolith simulants MLS-1 and MLS-2.^[41] Basalt fibre has also been made from lunar regolith simulators.

In August 2005, NASA contracted for the production of 16 tonnes of simulated lunar soil, or "Lunar Regolith Simulant Material."^[42] This material is now commercially available for research on how lunar soil could be utilized in situ.^[43]

Martian moons, Ceres, asteroids

Other proposals^[44] are based on Phobos and Deimos. These moons are in reasonably high orbits above Mars, have very low escape velocities, and unlike Mars have return delta-v's from their surfaces to LEO which are less than the return from the Moon.

Ceres is further out than Mars, with a higher delta-v, but launch windows and travel times are better, and the surface gravity is just 0.028 g, with a very low escape velocity of 510 m/s. Researchers have speculated that the interior configuration of Ceres includes a water-ice-rich mantle over a rocky core.^[45]

Near Earth Asteroids and bodies in the asteroid belt could also be sources of raw materials for ISRU.

Planetary atmospheres

Proposals have been made for "mining" for rocket propulsion, using what is called a Propulsive Fluid Accumulator. Atmospheric gases like oxygen and argon could be extracted from the atmosphere of planets like the Earth, Mars, and the outer Gas Giants by Propulsive Fluid Accumulator satellites in low orbit.^[46]

ISRU capability classification (NASA)

In October 2004, NASA’s Advanced Planning and Integration Office commissioned an ISRU capability roadmap team. The team's report, along with those of 14 other capability roadmap teams, were published May 22, 2005.^[47] The report identifies seven ISRU capabilities:^[47]:278 (i) resource extraction, (ii) material handling and transport, (iii) resource processing, (iv) surface manufacturing with in situ resources, (v) surface construction, (vi) surface ISRU product and consumable storage and distribution, and (vii) ISRU unique development and certification capabilities.

The report focuses on lunar and martian environments. It offers a detailed timeline^[47]:274 and capability roadmap to 2040^[47]:280-281 but it assumes lunar landers in 2010 and 2012.^[47]:280

ISRU technology demonstrators and prototypes

The Mars Surveyor 2001 Lander was intended to carry to Mars a test payload, MIP (Mars ISPP Precursor), that was to demonstrate manufacture of oxygen from the atmosphere of Mars,^[48] but the mission was cancelled.

The Mars Oxygen ISRU Experiment (MOXIE) is a 1% scale prototype model aboard the planned Mars 2020 rover that will produce oxygen from Martian atmospheric carbon dioxide (CO₂) in a process called solid oxide electrolysis.^{[49][50][51][52]}

Theory of predictive brain as important as evolution – Prof. Lars Muckli

This post Theory of predictive brain as important as evolution – Prof. Lars Muckli was originally published on Horizon: the EU Research & Innovation magazine | European Commission.


You have used advanced brain imaging techniques to come up with a model of how the brain processes vision – and it says that instead of just sorting through what we see, our brains actually anticipate what we will see next. Could you tell us a bit more?

‘We are interested to understand how the brain supports vision. A classical view had been that the brain is responding to visual information in a cascade of hierarchical visual areas with increasing complexity, but a more modern way is to realise that, actually, the brain is not meeting every situation with a clean sheet, but with lots of predictions.’

How does that work?

‘The main purpose of the brain, as we understand it today, is it is basically a prediction machine that is optimising its own predictions of the environment it is navigating through. So, vision starts with an expectation of what is around the corner. Once you turn around the corner, you are then negotiating potential inputs to your predictions – and then responding differently to surprise and to fulfilment of expectations.

‘So that's what’s called the predictive processing framework, and it's a proposed unifying theory of the brain. It's basically creating an internal model of what's going to happen next.’

'Vision starts with an expectation of what is around the corner.'

Lars Muckli, Centre for Cognitive Neuroimaging, Glasgow, Scotland

Why does this happen?

‘First of all, the outside world is not in our brain so somehow we need to get something into our brain that is a useful description of what's happening – and that's a challenge.

‘We become painfully aware of this challenge if we try to simulate this in a computer model – how do we get information about the outside world into a computer model? The brain does that in an unsupervised way. It segments the visual input into object, background, foreground, context, people and so on, and no one ever gives the brain any kind of supervision to do so.

‘To have meaningful models of the world, you need to have something like a supervisor in your brain that says: “This is Object A. This is another object, and you need to find a name for this.” We don't have a supervisor, but we have something – and that's the currency of surprise. (The need) to minimise surprise is used as a supervisor.’

How does surprise help us form models?

‘You can pick up an object, drop it, and you have a very good model of how that should sound (and) where it should stop. If it would suddenly not do that, you need to update your internal models. Those would be very rare situations.’

How does this work in our everyday experience – when we’re cycling on the street, for example?

‘You have forward models, so while you're cycling, you predict the trajectory of the cars, of your own movement on the entire world, in real time. You update your predictions (of) the future model that you create in order to cycle through the city without being run over.

‘These models are very good because you have this experience, and only now and then you need to update these models, or you update them (in real time) because you're turning a corner. So you're updating with your memory, your predictions, and a slight slip of the internal model comes about because you're surprised: “Oh it's not this street.” So, while you're cycling, you're negotiating a future model with another future model because you're updating these creations of your predictions.’



You’ve been working with the Human Brain Project (HBP), which is building a massive data and computing network to study the brain. How does it link to your work?

‘The Human Brain Project brings together different disciplines from computer science, neuroscience, computational neuroscience, robotics and medicine trying to answer a very simple question: “How does the brain work?”

‘It’s interesting because you need to become explicit about the model that each scientist has and use this on different scales and different species from mice to humans, from computational models to neuroscientific experiments and converge to a more general understanding. The predictive coding framework is something that is (being) tested by several teams within the HBP.

‘(To use a metaphor), if you want to build a large airplane (like an) Airbus you have different pockets in which you design the wheels, the aerodynamics of the wings and sub-parts and sub-materials. It is the vision of combining which drives the different groups, and that’s important because you work on small models, but having the idea of combining it drives the innovation.’

What’s next for your pursuit of brain science?

‘There is one thing that interests me a lot. We seem to have this capability of mind-wandering and predicting alternative scenarios in (the) future. We think about: “What am I going to do tonight? Should I go to the shops?” And you do this while you’re cycling on your bike and so on, and it seems like you’re doing three things at a time – thinking about planning your birthday, riding your bike and also calculating your next bill. There seems to be two scenarios, the emerging now, and the alternative – the plan.

‘How did this evolve? What are the rules? And how is this created? Since it’s happening in the brain, then we need to find a description for that – how is the mind wandering?’

What about your work motivates you?

‘I find the predictive coding framework a theory as important to brain science as evolution is to biology. It is the key explanation of how it makes sense that brains have been created through evolution to do a job for us and it is by creating predictions. The question of can we use this understanding for artificial systems (is) something that is ongoing and will keep us busy for a long time.’

The research in this article was funded by the EU’s European Research Council. If you liked this article, please consider sharing it on social media.

A Major Physics Experiment Just Detected A Particle That Shouldn't Exist

By Rafi Letzter, Staff Writer | June 1, 2018 04:49pm ET

Original link:  https://www.livescience.com/62721-sterile-neutrino-detected-fermilab.html?utm_source=notification 

The surface facility for the IceCube experiment, which is located under nearly 1 mile (1.6 kilometers) of ice in Antarctica. IceCube suggests ghostly neutrinos don't exist, but a new experiment says they do.

Credit: Courtesy of IceCube Neutrino Observatory

Scientists have produced the firmest evidence yet of so-called sterile neutrinos, mysterious particles that pass through matter without interacting with it at all.

The first hints these elusive particles turned up decades ago. But after years of dedicated searches, scientists have been unable to find any other evidence for them, with many experiments contradicting those old results. These new results now leave scientists with two robust experiments that seem to demonstrate the existence of sterile neutrinos, even as other experiments continue to suggest sterile neutrinos don't exist at all.

That means there's something strange happening in the universe that is making humanity's most cutting-edge physics experiments contradict one another.

Sterile neutrinos

Back in the mid-1990s, the Liquid Scintillator Neutrino Detector (LSND), an experiment at Los Alamos National Laboratory in New Mexico, found evidence of a mysterious new particle: a "sterile neutrino" that passes through matter without interacting with it. But that result couldn't be replicated; other experiments simply couldn't find any trace of the hidden particle. So the result was set aside.

Now, MiniBooNE — a follow-up experiment at Fermi National Accelerator Laboratory (Fermilab), located near Chicago — has picked up the hidden particle's scent again. A new paper posted to the preprint server arXiv offers such a compelling enough the missing neutrino to make physicists sit up and notice.

If MiniBooNE's new results hold up, "That would be huge; that's beyond the standard model; that would require new particles ... and an all-new analytical framework," said Kate Scholberg, a particle physicist at Duke University who was not involved in the experiment.

The Standard Model of physics has dominated scientists' understanding of the universe for more than half a century. It amounts to a list of particles that, together, go a long way toward explaining how matter and energy interact in the cosmos. Some of these particles, like quarks and electrons, are pretty easy to imagine: They're the building blocks of the atoms that make up everything we'll ever touch with our hands. Others, like the three known neutrinos, are more abstract: They're high-energy particles that stream through the universe, barely interacting with other matter. Billions of neutrinos from the sun pass through the tip of your finger every second, but they're overwhelmingly unlikely to have any impact on the particles of your body.

Electron, muon and tau neutrinos — the three known "flavors" — do interact with matter, though, through both the weak force (one of the four fundamental forces of the universe) and gravity. (Their antimatter twins sometimes interact with matter as well.) That means specialized detectors can find them, streaming down from the sun as well as from certain human sources, such as nuclear reactions. But the LSND experiment, Scholberg told Live Science, provided the first firm evidence that what humans could detect might not be the full picture.

As waves of neutrinos stream through space, they periodically "oscillate," jumping back and forth between one flavor and another, she explained. Both LSND and MiniBooNE involve firing beams of neutrinos at a detector hidden behind an insulator to block out all other radiation. (In LSND, the insulator was water; in MiniBooNE, it's a vat of oil.) And they carefully count how many neutrinos of each type strike the detector.

Both experiments have now reported more neutrino detections than The Standard Model's description of neutrino oscillation can explain the authors wrote in the paper. That suggests, they wrote, that the neutrinos are oscillating into hidden, heavier, "sterile" neutrinos that the detector can't directly detect before oscillating back into the detectable realm. The MiniBooNE result had a standard deviation measured at 4.8 sigma, just shy of the 5.0 threshold physicists look for. (A 5-sigma result has 1-in-3.5-million odds of being the result of random fluctuations in the data.) The researchers wrote that MiniBooNE and LSND combined represent a 6.1-sigma result (meaning more than one-in-500 million odds of being a fluke), though some researchers expressed a degree of skepticism about that claim.

If LSND and MiniBooNE were the only neutrino experiments on Earth, Scholberg said, that would be the end of the matter. The Standard Model would be updated to include some sort of sterile neutrino.

But there's a problem. Other major neutrino experiments, like the underground Oscillation Project with Emulsion-Tracking Apparatus experiment in Switzerland, haven't found the anomaly that both LSND and MiniBooNE have now seen.

As recently as 2017, after the IceCube Neutrino Observatory in Antarctica failed to turn up evidence for sterile neutrinos, researchers made the case to Live Science that another reported signal of the particles — missing antineutrinos around nuclear reactors — had been a mistake, and was actually the result of bad calculations.

Sterile neutrinos weren't a rejected idea, Scholberg said, but they weren't accepted science.

The MiniBooNE result complicates the particle picture.

"There are people who doubt the result," she said, "but there's no reason to think there's anything wrong [with the experiment itself]."

It's possible, she said, that the anomaly in the LSND and MiniBooNE experiments might turn out to be the "systematics," meaning there's something about the way neutrinos are interacting with the experimental setup that scientists don't yet understand. But it's also looking more and more possible that scientists are going to have to explain why so many other experiments aren't spotting very real sterile neutrinos that are turning up in Fermilab and Los Alamos Lab. And if that's the case, they'll have to revise their entire understanding of the universe in the process.