Lunar habitation is any human habitation on the Moon. Lunar habitation is provided by surface habitats, possibly as part of a moonbase.
History
Lunar habitats have been designed for many different proposed moonbases. The only lunar habitats to have been erected thus far were the temporary Apollo Lunar Modules, such as Eagle of Tranquility Base, the first. As of 2024, two programs, the US-led Artemis program and Chinese-led International Lunar Research Station aim to establish permanent surface settlements.
Analysis
Setting up structures on a natural body would provide ample sources of material for their construction, particularly for purposes such as shielding from cosmic radiation. The energy required to send objects from the Moon to space is much less than from Earth to space. This could allow the Moon to serve as a source of construction materials within cis-lunar space. Rockets launched from the Moon would require less locally produced propellant than rockets launched from Earth. Some proposals include using electric acceleration devices (mass drivers) to propel objects off the Moon without building rockets. Others have proposed momentum exchange tethers (see below). Furthermore, the Moon does have some gravity, which experience to date indicates may be vital for fetal development and long-term human health. Whether the Moon's gravity (roughly one sixth of Earth's) is adequate for this purpose is uncertain. In addition, the Moon is the closest large body in the Solar System to Earth. While some Earth-crosser asteroids occasionally pass closer, the Moon's distance is consistently within a small range close to 384,400 km.
Advantages
Building observatory facilities on the Moon from lunar materials allows many of the benefits of space based facilities without the need to launch these into space. The lunar soil, although it poses a problem for any moving parts of telescopes, can be mixed with carbon nanotubes and epoxies in the construction of mirrors up to 50 meters in diameter. It is relatively nearby; astronomical seeing is not a concern; certain craters near the poles are permanently dark and cold, and thus especially useful for infrared telescopes; and radio telescopes on the far side would be shielded from the radio chatter of Earth. A lunar zenith telescope can be made cheaply with ionic liquid. A farm at the lunar north pole could provide eight hours of sunlight per day during the local summer by rotating crops in and out of the sunlight which is continuous for the entire summer. A beneficial temperature, radiation protection, insects for pollination, and all other plant needs could be artificially provided during the local summer for a cost. One estimate suggested a 0.5 hectare space farm could feed 100 people.
Disadvantages
The long lunar night would impede reliance on solar power and require that a facility exposed to the sunlit equatorial surface be designed to withstand large temperature extremes (about to about ). An exception to this restriction are the so-called "peaks of eternal light" located at the lunar north pole that are constantly bathed in sunlight. The rim of Shackleton Crater, towards the lunar south pole, also has a near-constant solar illumination. Other areas near the poles that get light most of the time could be linked in a power grid. The temperature 1 meter below the surface of the Moon is estimated to be near constant over the period of a month varying with latitude from near at the equator to near at the poles.McGRAW-HILL ENCYCLOPEDIA OF Science & Technology, vol 11, 8th Edition, (c) 1997, p. 470 This could be used as a heat reservoir. The Moon is highly depleted in volatile elements, such as nitrogen and hydrogen. Carbon, which forms volatile oxides, is also depleted. A number of robot probes including Lunar Prospector gathered evidence of hydrogen generally in the Moon's crust consistent with what would be expected from solar wind, and higher concentrations near the poles. There had been some disagreement whether the hydrogen must necessarily be in the form of water. The 2009 mission of the Lunar Crater Observation and Sensing Satellite (LCROSS) proved that there is water on the Moon. This water exists in ice form perhaps mixed in small crystals in the regolith in a colder landscape than has ever been mined. Other volatiles containing carbon and nitrogen were found in the same cold trap as ice.PSRD CosmoSparks Report--An Icy Treat If no sufficient means is found for recovering these volatiles on the Moon, they would need to be imported from some other source to support life and industrial processes. Volatiles would need to be stringently recycled. This would limit any growth and keep the habitat dependent on imports. Transport costs would be reduced by a lunar space elevator if and when one can be constructed. The 2006 announcement by the Keck Observatory that the binary Trojan asteroid 617 Patroclus, and possibly large numbers of other Trojan objects in Jupiter's orbit, are likely composed of water ice, with a layer of dust, and the hypothesized large amounts of water ice on the closer, main-belt asteroid 1 Ceres, suggest that importing volatiles from this region via the Interplanetary Transport Network may be practical in the not-so-distant future. These possibilities are dependent on complicated and expensive resource utilization from the mid to outer Solar System, which is not likely to become available for a significant period of time. The lack of a substantial atmosphere for insulation results in temperature extremes and makes the Moon's surface conditions somewhat like a deep space vacuum with surface pressure (night) of 3 × 10−15 bar. It also leaves the lunar surface exposed to half as much radiation as in interplanetary space (with the other half blocked by the Moon itself underneath the habitat), raising the issues of the health threat from cosmic rays and the risk of proton exposure from the solar wind. In 2020 scientists reported the first ever measurements, made via China's Chang'e 4 lander, of the radiation exposure dose on the lunar surface. Lunar rubble can protect living quarters from cosmic rays.NASA, A Tour of the Colony Shielding against solar flares during expeditions outside is more problematic. When the Moon passes through the magnetotail of the Earth, the plasma sheet whips across its surface. Electrons crash into the Moon and are released again by UV photons on the day side but build up voltages on the dark side. This causes a negative charge build up from −200 V to −1000 V. See Magnetic field of the Moon. Moon dust is an extremely abrasive glassy substance formed by micrometeorites and unrounded due to the lack of weathering. It sticks to everything, can damage equipment, and it may be toxic. Since it is bombarded by charged particles in the solar wind, it is highly ionized, and is extremely harmful when breathed in. During the 1960s and 1970s Apollo missions, astronauts were subject to respiratory problems on return flights from the Moon, for this reason. Growing crops on the Moon faces many difficult challenges due to the long lunar night (354 hours), extreme variation in surface temperature, exposure to solar flares, soil with almost no nitrogen and little potassium, and lack of insects for pollination. Due to the lack of any atmosphere of substance on the Moon, plants would need to be grown in sealed chambers, though experiments have shown that plants can thrive at pressures much lower than those on Earth. The use of electric lighting to compensate for the 354-hour night might be difficult: a single acre (0.405 hectare) of plants on Earth enjoys a peak 4 megawatts of sunlight power at noon. Experiments conducted by the Soviet space program in the 1970s suggest it is possible to grow conventional crops with the 354-hour light, 354-hour dark cycle. A variety of concepts for lunar agriculture have been proposed, including the use of minimal artificial light to maintain plants during the night and the use of fast-growing crops that might be started as seedlings with artificial light and be harvestable at the end of one lunar day. An experiment in the Chinese Chang'e 4 lunar lander mission demonstrated that seeds could sprout and grow in protected conditions on the Moon (January 2019). The cotton seeds were able to handle the harsh conditions, at least initially, becoming the first plants ever to sprout on the surface of another world. But without a source of heat, the plants died in the cold lunar night. Lampenflora which grows in caves that have fixed artificial light sources installed shows that plants exist that need very little light to survive.
Energy
Nuclear power
A nuclear fission reactor might fulfill most of a Moon base's power requirements. With the help of fission reactors, one could overcome the difficulty of the 354 hour lunar night. According to NASA, a nuclear fission power station could generate a steady 40 kilowatts, equivalent to the demand of about eight houses on Earth. An artist's concept of such a station published by NASA envisages the reactor being buried below the Moon's surface to shield it from its surroundings; out from a tower-like generator part reaching above the surface over the reactor, radiators would extend into space to send away any heat energy that may be left over.Kathleen Zona: IMAGE FOR RELEASE 08-042. National Aeronautics and Space Administration, September 10, 2008, retrieved June 27, 2011
Radioisotope thermoelectric generators could be used as backup and emergency power sources for solar powered facilities. The needed radioisotopes could either be imported from earth as they are relatively energy-dense, or produced in situ by neutron irradiation of suitable materials (e.g. - an unavoidably produced minor actinide in fission reactors operating with thermal neutrons - to produce the commonly used ) or separated chemically from the high level waste of the nuclear reactor (e.g. Americium-241). Such nuclear batteries have been used for decades in spacecraft by all major spacefaring nations and some have even been implanted in humans as power sources for medical devices such as pacemakers, meaning their behavior and tradeoffs are well understood.
The Japanese spacecraft Kaguya confirmed the existence of both uranium and thorium near the lunar surface, which might in the future allow for the local production of nuclear fission fuel from lunar resources. However, concentrations are relatively low and unless the thorium fuel cycle is used, uranium would likely have to be enriched to produce fuel usable in light water reactors. The isotopic composition of lunar uranium is not known, but there is little reason to assume it would differ much from that found on earth (99% , ~0.72% , 55 ppm ). Nuclear reprocessing in situ would reduce the need for enrichment or imported fuel from earth. Pyroprocessing, which has been demonstrated at the Integral Fast Reactor prototype operated by Argonne National Laboratory, could be used instead of the de facto standard PUREX which requires large amounts of organic solvents.
One specific development program in the 2000s was the Fission Surface Power (FSP) project of NASA and DOE, a fission power system focused on "developing and demonstrating a nominal 40 kWe power system to support human exploration missions. The FSP system concept uses conventional low-temperature stainless steel, liquid metal-cooled reactor technology coupled with Stirling power conversion." By 2010, significant component hardware testing had been successfully completed, and a non-nuclear system demonstration test was being fabricated.