Commercial use of space

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A DIRECTV satellite dish on a roof

Commercial use of space is the provision of goods or services of commercial value by using equipment sent into Earth orbit or outer space. This phenomenon – aka Space Economy (or New Space Economy) – is accelerating cross-sector innovation processes combining the most advanced space and digital technologies to develop a broad portfolio of space-based services. The use of space technologies and of the data they collect, combined with the most advanced enabling digital technologies is generating a multitude of business opportunities that include the development of new products and services all the way to the creation of new business models, and the reconfiguration of value networks and relationships between companies. If well leveraged such technology and business opportunities can contribute to the creation of tangible and intangible value, through new forms and sources of revenue, operating efficiency and the start of new projects leading to multidimensional (e.g. society, environment) positive impact. Examples of the commercial use of space include satellite navigation, satellite television and commercial satellite imagery. Operators of such services typically contract the manufacturing of satellites and their launch to private or public companies, which form an integral part of the space economy. Some commercial ventures have long-term plans to exploit natural resources originating outside Earth, for example asteroid mining. Space tourism, currently an exceptional activity, could also be an area of future growth, as new businesses strive to reduce the costs and risks of human spaceflight.

The first commercial use of outer space occurred in 1962, when the Telstar 1 satellite was launched to transmit television signals over the Atlantic Ocean. By 2004, global investment in all space sectors was estimated to be $50.8 billion. As of 2010, 31% of all space launches were commercial.

History

The first commercial use of satellites may have been the Telstar 1 satellite, launched in 1962, which was the first privately sponsored space launch, funded by AT&T and Bell Telephone Laboratories. Telstar 1 was capable of relaying television signals across the Atlantic Ocean, and was the first satellite to transmit live television, telephone, fax, and other data signals. Two years later, the Hughes Aircraft Company developed the Syncom 3 satellite, a geosynchronous communications satellite, leased to the Department of Defense. Commercial possibilities of satellites were further realized when the Syncom 3, orbiting near the International Date Line, was used to telecast the 1964 Olympic Games from Tokyo to the United States.

Between 1960 and 1966, NASA launched a series of early weather satellites known as Television Infrared Observation Satellites (TIROS). These satellites greatly advanced meteorology worldwide, as satellite imagery was used for better forecasting, for both public and commercial interests.

On April 6, 1965, the Hughes Aircraft Company placed the Intelsat I communications satellite geosynchronous orbit over the Atlantic Ocean. Intelsat I was built for the Communications Satellite Corporation (COMSAT), and demonstrated that satellite-based communication was commercially feasible. Intelsat I allowed for near-instantaneous contact between Europe and North America by handling television, telephone and fax transmissions. Two years later, the Soviet Union launched the Orbita satellite, which provided television signals across Russia, and started the first national satellite television network. Similarly, the 1972 Anik A satellite, launched by Telesat Canada, allowed the Canadian Broadcasting Corporation to reach northern Canada for the first time.

Beginning in 1997, Iridium Communications began launching a series of satellites known as the Iridium satellite constellation, which provided the first satellites for direct satellite telephone service.

Spaceflight

Delta IV Medium launch carrying DSCS III-B6

The commercial spaceflight industry derives the bulk of its revenue from the launching of satellites into the Earth's orbit. Commercial launch providers typically place private and government satellites into low Earth orbit (LEO) and geosynchronous Earth orbit (GEO).

The Federal Aviation Administration (FAA) has licensed four commercial spaceports in the United States: Wallops Flight Facility, Kodiak Launch Complex, Spaceport Florida, Kennedy Space Center, Cape Canaveral Space Force Station, and the Vandenberg Air Force Base. Launch sites within Russia, France and China have added to the global commercial launch capacity. The Delta IV and Atlas V family of launch vehicles are made available for commercial ventures for the United States, while Russia promotes eight families of vehicles.

Between 1996 and 2002, 245 launches were made for commercial ventures while government (non-classified) launches only total 167 for the same period. Commercial space flight has spurred investment into the development of an efficient reusable launch vehicle (RLV) which can place larger payloads into orbit. Several companies such as SpaceX and Blue Origin are currently developing new RLV designs.

In the United States, Office of Commercial Space Transportation (generally referred to as FAA/AST or simply AST) is the branch of Federal Aviation Administration (FAA) that approves any commercial rocket launch operations—that is, any launches that are not classified as model, amateur, or "by and for the government."

Satellites and equipment

Satellite manufacturing

Commercial satellite manufacturing is defined by the United States government as satellites manufactured for civilian, government, or non-profit use. Not included are satellites constructed for military use, nor for activities associated with any human space flight program. Between the years of 1996 and 2002, satellite manufacturing within the United States experienced an annual growth of 11 percent. The rest of the world experienced higher growth levels of around 13 percent.

Ground equipment manufacturing

Operating satellites communicate via receivers and transmitters on Earth. The manufacturing of satellite ground station communication terminals (including VSATs), mobile satellite telephones, and home television receivers are a part of the ground equipment manufacturing sector. This sector grew through the latter half of the 1990s as it manufactured equipment for the satellite services sector. Between the years of 1996 and 2002 this industry saw a 14 percent annual increase.

Transponder leasing

Businesses that operate satellites often lease or sell access to their satellites to data relay and telecommunication firms. This service is often referred to as transponder leasing. Between 1996 and 2002, this industry experienced a 15 percent annual growth. The United States accounts for about 32 percent of the world's transponder market.

Subscription satellite services

In 1994, DirecTV debuted direct broadcast satellite by introducing a signal receiving dish 18inches in diameter. In 1996, Astro started in Malaysia with the launch of the MEASAT satellite. In November 1999, the Satellite Home Viewer Improvement Act became law, and local stations were then made available in satellite channel packages, fueling the industry's growth in the years that followed. By the end of 2000, DTH subscriptions totaled over 67 million.

Satellite radio was pioneered by XM Satellite Radio and Sirius Satellite Radio. XM's first satellite was launched on March 18, 2001 and its second on May 8, 2001. Its first broadcast occurred on September 25, 2001, nearly four months before Sirius. Sirius launched the initial phase of its service in four cities on February 14, 2002, expanding to the rest of the contiguous United States on July 1, 2002. The two companies spent over $3 billion combined to develop satellite radio technology, build and launch the satellites, and for various other business expenses.

Satellite imagery

Satellite imagery (also Earth observation imagery or spaceborne photography) are images of Earth or other planets collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell images by licensing them to governments and businesses such as Apple Maps and Google Maps.

Satellite navigation

Magellan GPS receiver in a marine application.

A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows small electronic receivers to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few centimeters to metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the positioning information generated.

Space tourism

Virgin Galactic VMS Eve

Main article: Space tourism

Space tourism is human space travel for recreational purposes. There are several different types of space tourism, including orbital, suborbital and lunar space tourism. To date, orbital space tourism has been performed only by the Russian Space Agency. Work also continues towards developing suborbital space tourism vehicles. This is being done by aerospace companies like Blue Origin and Virgin Galactic. In addition, SpaceX (an aerospace manufacturer) announced in 2018 that they are planning on sending space tourists, including Yusaku Maezawa, on a free-return trajectory around the Moon on the Starship.

Commercial recovery of space resources

Artist's concept of asteroid mining

Commercial recovery of space resources is the exploitation of raw materials from asteroids, comets and other space objects, including near-Earth objects. Minerals and volatiles could be mined then used in space for in-situ utilization (e.g. construction materials and rocket propellant) or taken back to Earth. These include gold, iridium, silver, osmium, palladium, platinum, rhenium, rhodium, ruthenium and tungsten for transport back to Earth; iron, cobalt, manganese, molybdenum, nickel, aluminium, and titanium for construction; water and oxygen to sustain astronauts; as well as hydrogen, ammonia, and oxygen for use as rocket propellant.

There are several commercial enterprises working in this field, including Planetary Resources and Deep Space Industries.

Regulation

Beyond the many technological factors that could make space commercialization more widespread, it has been suggested that the lack of private property, the difficulty or inability of individuals in establishing property rights in space, has been an impediment to the development of space for both human habitation and commercial development.

Since the advent of space technology in the latter half of the twentieth century, the ownership of property in space has been murky, with strong arguments both for and against. In particular, the making of national territorial claims in outer space and on celestial bodies has been specifically proscribed by the Outer Space Treaty, which had been, as of 2012, ratified by all spacefaring nations.

In November 25, 2015 President Obama signed the U.S. Commercial Space Launch Competitiveness Act (H.R. 2262) into law. The law recognizes the right of U.S. citizens to own space resources they obtain and encourages the commercial exploration and utilization of resources from asteroids. According to the article § 51303 of the law:

A United States citizen engaged in commercial recovery of an asteroid resource or a space resource under this chapter shall be entitled to any asteroid resource or space resource obtained, including to possess, own, transport, use, and sell the asteroid resource or space resource obtained in accordance with applicable law, including the international obligations of the United States.

In situ resource utilization

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ISRU reverse water gas shift testbed (NASA KSC)

In space exploration, in situ resource utilization (ISRU) is the practice of collection, processing, storing and use of materials found or manufactured on other astronomical objects (the Moon, Mars, asteroids, etc.) that replace materials that would otherwise be brought from Earth.

ISRU could 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.

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 utilization will enable the affordable establishment of extraterrestrial exploration and operations by minimizing the materials carried from Earth."

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 production has been proposed from the Moon's surface by processing water ice detected at the poles. The likely difficulties include working at extremely low temperatures and extraction from the regolith. Most schemes electrolyse the water to produce hydrogen and oxygen and cryogenically store them as liquids. This requires large amounts of equipment and power to achieve. Alternatively, it may be possible to heat water in a nuclear or solar thermal rocket, which may be able to deliver a large mass from the Moon to low Earth orbit (LEO) in spite of the much lower specific impulse, for a given amount of equipment.

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

Aluminum as well as other metals has been proposed for use as rocket propellant made using lunar resources, and proposals include reacting the aluminum with water.

For Mars, methane propellant can be manufactured via the Sabatier process. SpaceX has suggested building a propellant plant on Mars that would use this process to produce methane (CH
₄) and liquid oxygen (O₂) from sub-surface water ice and atmospheric CO
₂.

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. In fact, the native vacuum on the lunar surface provides an excellent environment for direct vacuum deposition of thin-film materials for solar cells.

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 launched into Earth orbit and assembled, with the resultant generated power being transmitted down to Earth via microwave beams. 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.

Building materials

The colonization of planets or moons will require obtaining 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.

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.

Locations

Mars

ISRU research for Mars is focused primarily on providing rocket propellant for a return trip to Earth — either for a crewed 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.

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.

As of 2018, SpaceX is 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 Starship no earlier than 2023.

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, and has been implemented in an Earth-based testbed by NASA. Again, hydrogen 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 is the electrolysis of the atmospheric carbon dioxide,

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

It has also been proposed the in situ production of oxygen, hydrogen and CO from the Martian hematite deposits via a two-step thermochemical CO
2/H₂O splitting process, and specifically in the magnetite/wustite redox cycle. 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 (> 2,500 °C) to achieve a useful dissociation fraction. 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, 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:

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

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.

However, the process needs wustite (FeO) 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. The use of wustite from the hematite, abundantly available on Mars, is an industrial process well known on Earth, and is performed by the following two main reduction reactions:

3Fe₂O₃ + H₂ → 2Fe₃O₄ + H₂O

3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂

The proposed 2001 Mars Surveyor lander was to demonstrate manufacture of oxygen from the atmosphere of Mars, and test solar cell technologies and methods of mitigating the effect of Martian dust on the power systems, but the project was cancelled. The proposed Mars 2020 rover mission might include ISRU technology demonstrator that would extract CO₂ from the atmosphere and produce O₂ for rocket fuel.

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.

All of the resources required to make plastics exist on Mars. 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. 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:

2CO + 4H₂ → C₂H₄ + 2H₂O.

Moon

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. Natural resources include solar power, oxygen, water, hydrogen, and metals.

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. One particular processing technique is to use fluorine brought from Earth as potassium fluoride to separate the raw materials from the lunar rocks.

Over twenty different methods have been proposed for oxygen extraction from the lunar regolith. 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.

Lunar materials may also be used as a general construction material, 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. Glass and glass fiber are straightforward to process on the Moon and Mars. Basalt fibre has also been made from lunar regolith simulators.

Successful tests have been performed on Earth using two lunar regolith simulants MLS-1 and MLS-2. In August 2005, NASA contracted for the production of 16 tonnes of simulated lunar soil, or lunar regolith simulant material for research on how lunar soil could be utilized in situ.

Martian moons, Ceres, asteroids

Other proposals 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.

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.

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 22 May 2005. The report identifies seven ISRU capabilities: (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 and capability roadmap to 2040 but it assumes lunar landers in 2010 and 2012.

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, 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.

The lunar Resource Prospector rover was designed to scout for resources on a polar region of the Moon, and it was proposed to be launched in 2022. The mission concept was still in its pre-formulation stage, and a prototype rover was being tested when it was scrapped in April 2018. Its science instruments will be flown instead on several commercial lander missions contracted by NASA's new Commercial Lunar Payload Services (CLSP) program, that aims to focus on testing various lunar ISRU processes by landing several payloads on multiple commercial landers and rovers. The first formal solicitation is expected sometime in 2019.

Mars to Stay

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https://en.wikipedia.org/wiki/Mars_to_Stay 

 

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!" and, in June 2013, Aldrin promoted a crewed mission "to homestead Mars and become a two-planet species". 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. The Mars Underground, Mars Homestead Project / Mars Foundation, Mars One (defunct in 2019), and Mars Artists Community advocacy groups and business organizations have also adopted Mars to Stay policy initiatives.

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".

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, 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. 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 some of the natural resources and elements necessary to sustain a robust, mature, industrialized human settlement—unlike, for example the Moon—a permanent Martian settlement is thought to be the most effective way to ensure that humanity becomes a space-faring, multi-planet species. 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.

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."

"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 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.

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. Mars One was a Dutch not-for-profit foundation, a Stichting. The proposal was to send a communication satellite and pathfinder lander to the planet by 2018 and, after several stages, land four humans on Mars for permanent settlement in 2027. A new set of four astronauts would then arrive every two years. 200,000 applications were started; about 2,500 were complete enough for consideration, from which one hundred applicants were chosen. Further selections were planned to narrow this down to six groups of four before training began in 2016. It was hoped that a reality television show, participant fees, and donations would generate the funding for the project.

The project was criticized by experts as a 'scam' and as 'delusional'. On January 15, 2019, a court decision was settled to liquidate the organization, sending it into bankruptcy administration.

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), 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. 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.

A comprehensive statement of a rationale for "Mars to Stay" was laid out by Buzz 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.

The Mars Artists Community has adopted Mars to Stay as their primary policy initiative. 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. 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.

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).

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.

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 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.

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".

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.

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!

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".

New York Times op-eds

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

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?" 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.

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 uncrewed 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."

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 human exploration. The answer lies with a one-way mission.

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 might be irreversibly harmed. Yet governments and scientific societies were willing sponsors of these enterprises." Davies then asks, "Why should it be different today?"