PIA23302-FirstHumansOnMars-ArtistConcept

A Mars habitat is a hypothetical place where humans could live on

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

. Mars habitats would have to contend with surface conditions that include almost no oxygen in the

air An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

, extreme cold, low pressure, and high radiation. Alternatively, the habitat might be placed underground, which helps solve some problems but creates new difficulties. One challenge is the extreme cost of transporting building materials to the Martian surface, which by the 2010s was estimated to be about US$2 million per brick. While the gravity on Mars is lower than that on

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

, there are stronger solar radiation and temperature cycles, and high internal forces needed for pressurized habitats to contain air. To contend with these constraints, architects have worked to understand the right balance between in-situ materials and construction, and ex-situ to Mars. For example, one idea is to use the locally available

regolith Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestria ...

to shield against radiation exposure, and another idea is to use transparent ice to allow non-harmful light to enter the habitat. Mars habitat design can also involve the study of local conditions, including pressures, temperatures, and local materials, especially water.

Overview

Significant challenges for Mars habitats are maintaining an artificial environment and shielding from intense

solar radiation Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically p ...

. Humans require a pressurized environment at all times and protection from the toxic Martian atmosphere. Connecting habitats is useful, as moving between separate structures requires a pressure suit or perhaps a Mars rover. One of the largest issues lies in simply getting to Mars, which means escaping Earth's atmosphere, sustaining the journey to Mars, and finally landing on the surface of Mars. One helpful aspect is the Mars atmosphere, which allows for aerobraking, meaning less need for using propellant to slow a craft for safe landing. However, the amount of energy required to transfer material to the surface of Mars is an additional task beyond simply getting into orbit. During the late 1960s, the United States produced the Saturn V rocket, which was capable of launching enough mass into orbit required for a single-launch trip holding a crew of three to the surface of the Moon and back again. This feat required a number of specially designed pieces of hardware and the development of a technique known as the

Lunar Orbit Rendezvous Lunar orbit rendezvous (LOR) is a process for landing humans on the Moon and returning them to Earth. It was utilized for the Apollo program missions in the 1960s and 1970s. In a LOR mission, a main spacecraft and a lunar lander travel to lunar or ...

. The Lunar Orbit Rendezvous was a plan to coordinate the descent and ascent vehicles for a rendezvous in Lunar orbit. Referring to Mars, a similar technique would require a

Mars Excursion Module The Mars Excursion Module (MEM) was a spacecraft proposed by NASA in the 1960s for use in a human mission to Mars, and this can refer to any number of studies by corporations and spaceflight centers for Mars landers. However, primarily a MEM referr ...

, which combines a crewed descent-ascent vehicle and short stay surface habitat. Later plans have separated the descent-ascent vehicle and surface habitat, which further developed into separate descent, surface stay, and ascent vehicles using a new design architecture. In 2010 the

Space Launch System The Space Launch System (SLS) is an American Super heavy-lift launch vehicle, super heavy-lift Expendable launch system, expendable launch vehicle used by NASA. As the primary launch vehicle of the Artemis program, Artemis Moon landing progra ...

, or growth variants therefore, is envisioned as having the payload capacity and qualities needed for human Mars missions, utilizing the Orion capsule. One of the challenges for Mars habitats is maintaining the climate, especially the right temperature in the right places. Electronic devices and lights generate heat that rises in the air, even as there are extreme temperature fluctuations outside. One idea for a Mars habitat is to use a Martian cave or

lava tube A lava tube, more rarely called a pyroduct, is a 'roofed conduit through which molten lava travels away from its vent'. If lava in the tube drains out, it will leave an empty cave. Lava tubes are common in low-viscosity volcanic systems. La ...

, and an inflatable air-lock was proposed by Caves of Mars Project for making use of such a structure. The idea of living in lava tubes has been suggested for their potential to provide increased protection from

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

, temperature fluctuation, Martian sunlight, etc. An advantage of living underground is that it avoids the need to create a radiation shield above ground. Another idea is to use robots to construct the base in advance of human's arrival. The use of living plants or other living biologicals to aid in the air and food supply if desired can have major impact on the design. An example of how

engineering Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, s ...

demands and operational goals can interact, is a reduced-pressure greenhouse area. This would reduce the structural demands of maintaining

air pressure Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The Standard atmosphere (unit), standard atmosphere (symbol: atm) is a unit of pressure defined as , whi ...

, but require the relevant plants to survive at that lower pressure. Taken to an extreme, the question remains just how a low a pressure could a plant survive in and still be useful. A Mars habitat may need to focus on keeping a certain type of plant alive, for example, as part of supporting its inhabitants. NASA's Caves of Mars study suggested the following food and food production characteristics: *Rapid growth *survival in low light *wide pH range *high

nutrition Nutrition is the biochemistry, biochemical and physiology, physiological process by which an organism uses food and water to support its life. The intake of these substances provides organisms with nutrients (divided into Macronutrient, macro- ...

*minimal waste The study noted two plants,

duckweed Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose fr ...

(''Lemna minor'') and water fern (''

Azolla filiculoides ''Azolla filiculoides'' (water fern) is a species of aquatic fern. It is native to warm temperate and tropical regions of the Americas, and has been introduced to Europe, North and sub-Saharan Africa, China, Japan, New Zealand, the Caribbean, an ...

''), as particularly suitable, and they grow on the surface of water. The Mars habitat would have to support the conditions of these food sources, possibly incorporating elements from greenhouse design or farming. Historically, space missions tend to have a non-growing food supply eating out of set amount of rations like

Skylab Skylab was the United States' first space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three trios of astronaut crews: Skylab 2, Skylab 3, and Skylab 4. Skylab was constructe ...

, replenished with resupply from Earth. Using plants to affect the atmosphere and even enhance food supply was experimented with the 2010s aboard the

International Space Station The International Space Station (ISS) is a large space station that was Assembly of the International Space Station, assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United ...

. Another issue is waste management. On Skylab all waste was put in a big tank; on Apollo and the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

urine could be vented out into space or pushed away in bags to re-enter Earth's atmosphere. Considerations for maintaining the environment in a closed system included, removal of carbon dioxide, maintaining air pressure, supply of oxygen, temperature and humidity, and stopping fires. Another issue with closed system is keeping it free from contamination from emissions from different materials, dust, or smoke. One concern on Mars is the effect of the fine dust of the

Martian soil Martian regolith is the fine blanket of unconsolidated, loose, heterogeneous superficial deposits covering the surface of Mars. The term ''Martian soil'' typically refers to the finer fraction of regolith. So far, no samples have been returned to ...

working its way into the living quarters or devices. The dust is very fine and accumulates on solar panels, amongst other surfaces.

Relevant technologies

Some possible areas of needed technology or expertise: *

3D Printing 3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

Mars atmospheric entry Mars atmospheric entry is the atmospheric entry, entry into the atmosphere of Mars. High velocity entry into Martian air creates a CO2-N2 plasma, as opposed to O2-N2 for Earth air.Caves of Mars Project *

Aerospace engineering Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is s ...

Space capsule A space capsule is a spacecraft designed to transport cargo, scientific experiments, and/or astronauts to and from space. Capsules are distinguished from other spacecraft by the ability to survive reentry and return a payload to the Earth's surfa ...

Plants in space The growth of plants in outer space has elicited much scientific interest. In the late 20th and early 21st century, plants were often taken into space in low Earth orbit to be grown in a weightless but pressurized controlled environment, sometime ...

Context

A Mars habitat is often conceived as part of an ensemble of Mars base and infrastructure technologies. Some examples include Mars EVA suits, Mars rover, aircraft, landers, storage tanks, communication structures, mining, and Mars-movers (e.g. Earth-moving equipment). A Mars habitat might exist in the context of a human expedition, outpost, or colony on Mars.

Air

In creating a habitat for people, some considerations are maintaining the right air temperature, the right air pressure, and the composition of that atmosphere. While it is possible for humans to breathe pure oxygen, a pure oxygen atmosphere was implicated in the

Apollo 1 Apollo 1, initially designated AS-204, was planned to be the first crewed mission of the Apollo program, the American undertaking to land the first man on the Moon. It was planned to launch on February 21, 1967, as the first low Earth orbital ...

fire. As such, Mars habitats may have a need for additional gases. One possibility is to take

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

and

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

from the

atmosphere of Mars The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.85%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and nob ...

; however, they are hard to separate from each other. As a result, a Mars habitat may use 40% argon, 40% nitrogen, and 20% oxygen. See also Argox, for the argon breathing gas mixture used in scuba diving A concept to scrub from the breathing air is to use re-usable

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

bead

carbon dioxide scrubber A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or ...

s. While one carbon dioxide scrubber filters the astronaut's air, the other can vent scrubbed to the Mars atmosphere, once that process is completed another one can be used, and the one that was used can take a break. Martian habitat with colonists

One unique structural force that Mars habitats must contend with if pressurized to Earth's atmosphere, is the force of air on the inside walls. This has been estimated at over for a pressurized habitat on the surface of Mars, which is radically increased compared to Earth structures. A closer comparison can be made to crewed high-altitude aircraft, which must withstand forces of when at altitude. At about 150 thousand feet of altitude (28 miles (45 km)) on Earth, the atmospheric pressure starts to be equivalent to the surface of Mars.

Temperature

One of the challenges for a Mars habitat is for it to maintain suitable temperatures in the right places in a habitat. Things like electronics and lights generate heat that rises in the air, even as there are extreme temperature fluctuation outside. There can be large temperature swings on Mars, for example at the equator it may reach 70 degrees F (20 degrees C) in the daytime but then go down to minus 100 degrees F (−73 C) at night. Examples of Mars surface temperatures: *Average −80 degrees Fahrenheit (−60 degrees Celsius). *Polar locations in winter −195 degrees F (−125 degrees C). *Equator in summer daytime High 70 degrees F (20 degrees C)

Temporary vs permanent habitation

A short term stay on the surface of Mars does not require a habitat to have a large volume or complete shielding from radiation. The situation would be similar to the

, where individuals receive an unusually high amount of radiation for a short duration and then leave. A small and light habitat can be transported to Mars and used immediately. Long term permanent habitats require much more volume (i.e.:

greenhouse A greenhouse is a structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight pass an ...

) and thick shielding to minimize the annual dose of radiation received. This type of habitat is too large and heavy to be sent to Mars, and must be constructed making use of some local resources. Possibilities include covering structures with ice or soil, excavating subterranean spaces or sealing the ends of an existing

. A larger settlement may be able to have a larger medical staff, increasing the ability to deal with health issues and emergencies. Whereas a small expedition of 4–6 may be able to have 1 medical doctor, an outpost of 20 might be able to have more than one and nurses, in addition to those with emergency or paramedic training. A full settlement may be able to achieve the same level of care as a contemporary Earth hospital.

Medical

One problem for medical care on Mars missions, is the difficulty in returning to Earth for advanced care, and providing adequate emergency care with a small crew size. A crew of six might have only one crew member trained to the level of emergency medical technician and one physician, but for a mission that would last years. In addition, consultations with Earth would be hampered by a 7 to 40 minute time lag. Medical risks include exposure to radiation and reduced gravity, and one deadly risk is a

Solar Particle Event In solar physics, a solar particle event (SPE), also known as a solar energetic particle event or solar radiation storm, is a solar phenomenon which occurs when particles emitted by the Sun, mostly protons, become accelerated either in the Sun's ...

that can generate a lethal dose over the course of several hours or days if the astronauts do not have enough shielding. Materials testing has recently been done to explore spacesuits and "storm shelters" for protection from Galactic Cosmic Radiation (GRC) and Solar Particle Events (SPE's) during launch, transit, and habitation upon Mars. Medical preparedness also requires that the effect of radiation on stored pharmaceuticals and medical technology would have to be taken into account as well. One of the medical supplies that may be needed is

intravenous fluid Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...

, which is mostly water but contains other things so it can be added directly to the blood stream. If it can be created on the spot from existing water then it could spare the weight of hauling earth-produced units, whose weight is mostly water. A prototype for this capability was tested on the

in 2010. On some of the first crewed missions, three types of medications that were taken into orbit; the

antiemetic An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer. They may ...

trimethobenzamide Trimethobenzamide (trade names Tebamide, Tigan) is an antiemetic used to prevent nausea and vomiting. Mechanism of action Trimethobenzamide is an antagonist of the D2 receptor. It is believed to affect the chemoreceptor trigger zone (CTZ) of ...

; the

painkiller An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...

pethidine Pethidine, also known as meperidine and sold under the brand name Demerol among others, is a fully synthetic opioid pain medication of the phenylpiperidine class. Synthesized in 1938 as a potential anticholinergic agent by the German chemist Ot ...

; the

stimulant Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognition, ...

dextroamphetamine Dextroamphetamine (international nonproprietary name, INN: dexamfetamine) is a potent central nervous system (CNS) stimulant and enantiomer of amphetamine that is used in the treatment of attention deficit hyperactivity disorder (ADHD) and narc ...

. By the time of ISS, space crew-persons had almost 200 medications available, with separate pill cabinets for Russians and Americans. One of the many concerns for crewed Mars missions is what pills to bring and how the astronauts would respond to them in different conditions. In 1999, NASA's Johnson Space Center published ''Medical Aspects of Exploration Missions'' as part of the

Decadal Survey A decadal survey is a 10-year plan outlining scientific missions and goals created by the United States National Academies. It is a summary of input from scientists in the United States and beyond. Examples include: * Astronomy and Astrophysics ...

. On a small mission it might be possible to have one be a medical doctor and another be a paramedic, out of a crew of perhaps 4–6 people, however on a larger mission with 20 people there could also be a nurse and options like minor surgery might be possible. Two major categories for space would be emergency medical care and then more advanced care, dealing with a wide range concerns due to space-travel. For very small crews its difficult to treat a wide range issues with advanced care, whereas with a team with an overall size of 12–20 on Mars there could be multiple doctors and nurses, in addition to EMT-level certifications. While not at the level of a typical Earth hospital this would transition medical are beyond basic options typical of very small crew sizes (2–3) where the accepted risk is higher. With a modest number of Mars inhabitants and medical crew,

robot-assisted surgery Robot-assisted surgery or robotic surgery are any types of surgical procedures that are performed using robotic systems. Robotically assisted surgery was developed to try to overcome the limitations of pre-existing minimally-invasive surgical ...

could be considered. A crew member would operate the robot with help via telecommunications from Earth. Two examples of medical-care situations that have been mentioned in regard to people on Mars is how to deal with a broken leg and an

appendicitis Appendicitis is inflammation of the Appendix (anatomy), appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, fever and anorexia (symptom), decreased appetite. However, approximately 40% of people do not have these t ...

. One concern is to stop what would otherwise be a minor injury from becoming life-threatening due to restrictions on the amount of

medical equipment A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...

, training, and the time-delay in communication with Earth. The time delay for a one way message ranges from 4 to 24 minutes, depending. A response to a message takes that time, the delay processing the message and creating a reply, plus the time for that message to travel to Mars (another 4 to 24 minutes). Examples of acute medical emergency scenarios for Mars missions: *Wounds, lacerations, and burns *Exposure to a toxin *Acute allergic reactions (

anaphylaxis Anaphylaxis (Greek: 'up' + 'guarding') is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of the use of emergency medication on site. It typicall ...

) * Acute radiation sickness *Dental *Eye (

Ophthalmologic Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

) *Psychiatric An example of spaceflight related health emergency was the

inert gas asphyxiation Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen (hypoxia), rather than atmospheric air (which is composed largely of nitrogen and oxygen ...

with nitrogen gas aboard Space Shuttle Columbia in 1981, when it was undergoing preparations for its launch In that case, a routine purge with nitrogen to decrease risk of fire lead to 5 medical emergencies and 2 deaths. Another infamous space related accident is the

incident, when a pure oxygen atmosphere ignited in the interior of space capsule during tests on the ground, three died. A 1997 study of about 280 space travelers between 1988 and 1995, found that only 3 did not have some sort of medical issue on their spaceflight. A medical risk for a Mars surface mission is how the astronauts will handle operations on the surface after several months in zero gravity. On Earth, astronauts are usually carted from the spacecraft and take a long time to recover. See

Space medicine Space Medicine is a subspecialty of Emergency Medicine (Fellowship Training Pathway) which evolved from the Aerospace Medicine specialty. Space Medicine is dedicated to the prevention and treatment of medical conditions that would limit success in ...

Library

One idea for a Mars missions is a

library A library is a collection of Book, books, and possibly other Document, materials and Media (communication), media, that is accessible for use by its members and members of allied institutions. Libraries provide physical (hard copies) or electron ...

sent to the surface of that planet. The Phoenix lander, which landed on the North polar surface of Mars in 2008, included a DVD library that was heralded as the first library on Mars. The Phoenix library DVD would be taken by future explorers who could access the content on the disk. The disc, both a memorial to the past and a message to the future, took 15 years to produce. The content on the disc includes ''Visions of Mars''. One idea for exploration is

knowledge ark A knowledge ark (also known as a doomsday ark or doomsday vault) is a collection of knowledge preserved in such a way that future generations would have access to said knowledge if all other copies of it were lost. Scenarios where access to info ...

s for space, a sort of back-up of knowledge in case something happens to Earth. The Biodome 2 spaceflight and closed-loop biosphere test included a library with the living quarters. The library was positioned at the top of a tower, and known as Library tower.

Meteor impacts

Another consideration for Mars habitats, especially for long-term stay, is the need to potentially deal with a meteor impact. Because the atmosphere is thinner, more meteors make it to the surface. So, one concern is that a meteor might puncture the surface of the habitat and thereby cause a loss of pressure and/or damage systems. In the 2010s it was determined that something struck the surface of Mars, creating a spattering pattern of larger and smaller craters between 2008 and 2014. In this case the atmosphere only partially disintegrated the meteor before it struck the surface.

Radiation

Radiation exposure is a concern for astronauts even on the surface, as Mars lacks a strong magnetic field, and atmosphere is too thin to stop as much radiation as Earth. However, the planet does reduce the radiation significantly especially on the surface, and it is not detected to be radioactive itself. It has been estimated that sixteen feet (5 meters) of Mars regolith stops the same amount of radiation as Earth's atmosphere.

Power

For a 500-day crewed Mars mission NASA has studied using solar power and nuclear power for its base, as well as power storage systems (e.g. batteries). Some of the challenges for solar power include a reduction in solar intensity (because Mars is farther from the sun), dust accumulation, periodic dust storms, and storing power for night-time use. Global Mars dust storms cause lower temperatures and reduce sunlight reaching the surface. Two ideas for overcoming this are to use an additional array deployed during a dust storm and to use some nuclear power to provide base-line power that is not affected by the storms. NASA has studied nuclear-power fission systems in the 2010s for Mars surface missions. One design planned an output of 40 kilowatts; nuclear power fission is independent of sunlight reaching the surface of Mars, which can be affected by dust storms. Another idea for power is to beam the power to the surface from a solar power satellite to a rectifying antenna (aka

rectenna A rectenna (''rect''ifying ant''enna'') is a special type of receiving antenna that is used for converting electromagnetic energy into direct current (DC) electricity. They are used in wireless power transmission systems that transmit power by r ...

) receiver. 245 GHz, laser, in-situ rectenna construction, and 5.8 GHz designs have been studied. One idea is combine this technology with Solar Electric Propulsion to achieve a lower mass than surface solar power. The big advantage of this approach to power is that the rectennas should be immune to dust and weather changes, and with the right orbit, a solar power Mars satellite could beam power down continuously to the surface. Technology to clean dust off the solar panels was considered for

Mars Exploration Rover NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rove ...

's development. In the 21st century ways have been proposed for cleaning off solar panels on the surface of Mars. The effects of Martian surface dust on

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

s was studied in the 1990s by the Materials Adherence Experiment on

Mars Pathfinder ''Mars Pathfinder'' was an American robotic spacecraft that landed a base station with a rover (space exploration), roving probe on Mars in 1997. It consisted of a Lander (spacecraft), lander, renamed the Carl Sagan Memorial Station, and a ligh ...

History

One early idea for a Mars habitat was to use put short stay accommodation in a Mars ascent-descent vehicle. This combination was called a

, and also typically featured other components such as basic rover and science equipment. Later missions tended to shift to a dedicated descent/ascent with a separate habitat. In 2013 ZA architects proposed having digging robots build a Mars habitat underground. They chose an interior inspired by

Fingal's Cave Fingal's Cave is a sea cave on the uninhabited island of Staffa, in the Inner Hebrides of Scotland, known for its natural acoustics. The National Trust for Scotland owns the cave as part of a national nature reserve (Scotland), national nature ...

and noted the increased protection from high-energy radiation below ground. On the other hand, the issue of the difficulty of sending digging robots that must construct the habitat versus landing capsules on the surface was also noted. An alternative may be to build above ground using thick ice to shield from radiation. This approach has the advantage of allowing light in. In 2015 the Self-deployable Habitat for Extreme Environments (SHEE) project explored the idea of autonomous construction and preparation for Mars habitat versus human construction, because the latter is "risky, complex, and costly."

NASA

In early 2015 NASA outlined a conceptual plan for a three stage Mars habitat design and construction award program. The first stage called for a design. The next stage requested plans for construction technology that used discarded spacecraft components. The third stage involved building a habitat using 3D printing technology. In September 2015, NASA announced the winners of its 3-D Printed Habitat Challenge. The winning submission titled Mars Ice House''' by Clouds Architecture Office / SEArch proposed a 3D-printed double ice shell surrounding a lander module core. Two European teams were awarded runner up prizes. The contenders explored many possibilities for materials, with one suggesting separately refining iron and silica from the Martian dust and using the iron to make a lattice-work filled in with silica panels. There were 30 finalists selected from an initial pool of 165 entries in the habitat challenge. The second-place winner proposed the printing robots build a shield out of in-situ materials around inflatable modules. Other NASA projects that have developed extraterrestrial surface habitats are the X-Hab challenge and the Habitation Systems Project. The Sfero House by Fabulous, also a contender in the 3D Mars Habitat program, featured levels above and below ground. The proposed location was Gale crater (of Curiosity rover fame) with a focus on using both in-situ iron and water, which would hopefully be available there. It has a double-walled spherical design filled with water to both keep the higher pressure of Mars habitat in but help protect against radiation. In 2016, NASA awarded the first prize of its In-Situ Materials Challenge to University of Southern California engineering professor Behrokh Khoshnevis "for Selective Separation Sintering -- a 3D-printing process that makes use of powder-like materials found on Mars." Mars Ice Home concept

In 2016 NASA Langley showed the Mars Ice Home, which used in-situ water to make an ice structure conceptually similar to an iglo, as part of the design of a Mars habitat. In June 2018, NASA selected the top ten finalists of Phase 3: Level 1 in the 3D-Printed Habitat Challenge. Phase 3: Level 1 Winners: *ALPHA Team – Marina Del Rey, California *

Colorado School of Mines The Colorado School of Mines (Mines) is a public research university in Golden, Colorado, United States. Founded in 1874, the school offers both undergraduate and graduate degrees in engineering, science, and mathematics, with a focus on ener ...

and ICON – Golden, Colorado *Hassell & EOC – San Francisco, California *Kahn-Yates – Jackson, Mississippi * Mars Incubator – New Haven, Connecticut *AI. SpaceFactory – New York, New York *

Northwestern University Northwestern University (NU) is a Private university, private research university in Evanston, Illinois, United States. Established in 1851 to serve the historic Northwest Territory, it is the oldest University charter, chartered university in ...

– Evanston, Illinois *SEArch+/Apis Cor – New York, New York *Team Zopherus – Rogers, Arkansas *X-Arc – San Antonio, Texas In May 2019, NASA announced that the top winner of the 3D Printed Habitat Challenge was from AI SpaceFactory, with an entry called "Marsha," and there was several other prizes awarded also. In the final challenge contestants had 30 hours to build 1/3 scale models using robotic construction technology.

Mars analogs and analog habitat studies

Mock Mars missions or Mars analog missions typically construct terrestrial habitats on Earth and conduct mock missions, taking steps to solve some of the problems that could be faced on Mars. An example of this was the original mission of

Biosphere 2 University of Arizona Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and i ...

, which was meant to test closed ecological systems to support and maintain human life in outer space. Biosphere 2 tested several people living in a closed loop biological system, with several biological support areas including rainforest, savannah, ocean, desert, marsh, agriculture, and a living space. An example of Mars analog comparison mission is

HI-SEAS The Hawaii Space Exploration Analog and Simulation (HI-SEAS) is an analog habitat for human spaceflight to Mars currently operated by the International MoonBase Alliance. HI-SEAS is located in an isolated position on the slopes of the Mauna L ...

of the 2010s. Other Mars analog studies include

Mars Desert Research Station The Mars Desert Research Station (MDRS) is the largest and longest-running Mars surface research facility and is one of two simulated Mars analog habitats owned and operated by the Mars Society. The MDRS station was built in the early 2000s ne ...

and Arctic Mars Analog Svalbard Expedition. * Australia Mars Analog Research Station *

Flashline Mars Arctic Research Station The Flashline Mars Arctic Research Station (FMARS) is the first of two simulated Mars habitats (or Mars Analog Research Stations) located on Devon Island, Nunavut, Canada, which is owned and operated by the Mars Society. The station is a member ...

MARS-500 The MARS-500 mission was a psychosocial isolation experiment conducted between 2007 and 2011 by Russia, the European Space Agency, and China, in preparation for an unspecified future crewed spaceflight to the planet Mars. The experiment's ...

Concordia Station Concordia Research Station, which opened in 2005, is a French–Italian research facility managed by l' Institut polaire français Paul-Émile Victor and Programma Nazionale di Ricerche in Antartide, that was built above sea level on a geogra ...

The ISS has also been described as a predecessor to Mars expedition, and in relation to a Mars habitat the study importance and nature of operation a closed system was noted. At about 28 miles (45 km, 150 thousand feet ) Earth altitude the pressure starts to be equivalent to Mars surface pressure. An example of regolith simulant is Martian regolith simulant (further information about Mars analogs

List of Mars analogs This is list of Mars analogs, which simulate aspects of the conditions human beings could experience during a future mission to Mars, or different aspects of Mars such as its materials or conditions. This is often used for testing aspects of spac ...

)

Biodomes

One example concept that is or is in support of habitat is a Mars biodome, a structure that could hold life generating needed oxygen and food for humans. An example of activity in support of this goals, was a program to develop bacteria that could convert the Martian regolith or ice into

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

. Some issues with biodomes are the rate at which gas leaks out and the level of oxygen and other gases inside it. One question for Biodomes is how low the pressure could be lowered to, and the plants still be useful. In one study where air pressure was lowered to 1/10 of Earth's air pressure at the surface, the plants had a higher rate of evaporation from its leaves. This triggered the plant to think there was drought, despite it having a steady supply of water. An example of a crop NASA tested growing at lower pressure is lettuce, and in another test

green beans Green beans are young, unripe fruits of various cultivars of the common bean (''Phaseolus vulgaris''), although immature or young pods of the runner bean ('' Phaseolus coccineus''), yardlong bean ( ''Vigna unguiculata'' subsp. ''sesquipedalis ...

were grown at a standard air pressure, but in low Earth orbit inside the International Space Station. The DLR found that some

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

and bacteria could survive in simulated Martian conditions, including air composition, pressure, and solar radiation spectrum. The Earth organisms survived for over 30 days under Mars conditions, and while it was not known if they would survive beyond this, it was noted they seemed to be performing

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

under those conditions. To convert the entirety of Mars into a biodome directly, scientists have suggested the

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

Chroococcidiopsis. This would help convert the regolith into soil by creating an organic element. That bacteria is known to survive in extremely cold and dry conditions on Earth, so might provide a basis for bioengineering Mars into a more habitable place. As the bacteria reproduces the dead ones would create an organic layer in the regolith potentially paving the way for more advanced life. A study published in 2016 showed that crypto

endolith An endolith or endolithic is an organism ( archaeon, bacterium, fungus, lichen, algae, sponge, or amoeba) that is able to acquire the necessary resources for growth in the inner part of a rock, mineral, coral, animal shells, or in the pores betw ...

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

survived for 18 months in simulated Mars conditions. On Earth, plants that utilize the C4 photosynthesis reaction account for 3% of flowering plant species but 23% of carbon that is fixed, and includes species popular for human consumption including corn (aka maize) and

sugar cane Sugarcane or sugar cane is a species of tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fib ...

; certain types of plants may be more productive at producing food for a given amount of light. Plants noted for colonizing the barren landscape in the aftermath of the Mt Saint Helen's eruption included

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

and

Epilobium ''Epilobium'' is a genus of flowering plants in the family Onagraceae, containing about 197 species. The genus has a worldwide distribution. It is most prevalent in the subarctic, temperate and subantarctic regions, whereas in the subtropics and ...

, and especially Lupinus lepidus for its (symbiotic) ability to fix its own nitrogen.

Rhizobia Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. I ...

bacteria are capable of fixing nitrogen.

In-situ resources

In situ resource utilization involves using materials encountered on Mars to produce materials needed. One idea for supporting a Mars habitat is to extract subterranean water, which, with sufficient power, could then be split into hydrogen and oxygen, with the intention of mixing the oxygen with nitrogen and argon for breathable air. The hydrogen can be combined with carbon dioxide to make plastics or methane for rocket fuel. Iron has also been suggested as a building material for 3D printed Mars habitats. In the 2010s the idea of using in-situ water to build an ice shield for protection from radiation and temperature, etc. appeared in designs. A material processing plant would use Mars resources to reduce reliance on Earth provided material. The planned

Mars 2020 Mars 2020 is a NASA mission that includes the rover ''Perseverance (rover), Perseverance'', the now-retired small robotic helicopter ''Ingenuity (helicopter), Ingenuity'', and associated delivery systems, as part of the Mars Exploration Progra ...

mission includes

Mars Oxygen ISRU Experiment The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) was a technology demonstration on the NASA Mars 2020 rover '' Perseverance'' investigating the production of oxygen on Mars. On April 20, 2021, MOXIE produced oxygen from carbon dio ...

(MOXIE), which would convert Mars carbon dioxide into oxygen. To convert the whole of Mars into a habitat, increased air could come from vaporizing materials in the planet. In time lichen and moss might be established, and then eventually pine trees. Combination Lander Concept on Mars Surface

Combination Lander Concept on Mars Surface

There is a theory to make rocket fuel on Mars, by the Sabatier process. In this process hydrogen and carbon dioxide are used to make methane and water. In the next step, the water is split into hydrogen and oxygen, with the oxygen and methane being used for a Methane-Oxygen rocket engine, and the hydrogen could be re-used. This process requires a large input of energy, so an appropriate power source would be needed in addition to the reactants.

References

External links

Mars Habitat NASA-CR-189985
(.pdf)
Mars Ice House by SEArch and Clouds AO project siteHuman health and radiation report (October 2015)
(NASA)
Norman and Fosters 3d printed Mars habitat design
{{Human missions to Mars Mars

Habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

Human habitats