question: Considering all the talk of colonising Marss, wouldn't it be easier to just make a moon base?
comment: There are pros and cons either way, as I understand it. For instance: the moon is closer, but mars has enough gravity to be more comfortable (and healthier), enough atmosphere to make insulation a far simpler problem, and enough weather that erosion has made the dust similar enough that we can say with confidence that we know how to deal with it - unlike the regolith on the moon which is a bit nightmarish.
passages: Ultimately a NASA-sponsored lunar outpost would be built, possibly near the Moon's south pole. But this decision has not yet been taken and might depend on potential international and commercial participation to the exploration project.
  
  Section::::Extension to Mars.
   The construction of an underground base would probably be more complex; one of the first machines from Earth might be a remote-controlled excavating machine. Once created, some sort of hardening would be necessary to avoid collapse, possibly a spray-on concrete-like substance made from available materials. A more porous insulating material also made "in-situ" could then be applied. Rowley & Neudecker have suggested "melt-as-you-go" machines that would leave glassy internal surfaces. Mining methods such as the room and pillar might also be used. Inflatable self-sealing fabric habitats might then be put in place to retain air. Eventually an underground city can be constructed. Farms set up underground would need artificial sunlight. As an alternative to excavating, a lava tube could be covered and insulated, thus solving the problem of radiation exposure.
   Nuclear power is sometimes proposed for colonies located on the Moon or on Mars, as the supply of solar energy is too discontinuous in these locations; the Moon has nights of two Earth weeks in duration. Mars has nights, relatively high gravity, and an atmosphere featuring large dust storms to cover and degrade solar panels. Also, Mars' greater distance from the Sun (1.5 astronomical units, AU) translates into "E/(1.5 = 2.25)" only ½–⅔ the solar energy of Earth orbit. Another method would be transmitting energy wirelessly to the lunar or Martian colonies from solar power satellites (SPSs) as described above; the difficulties of generating power in these locations make the relative advantages of SPSs much greater there than for power beamed to locations on Earth. In order to also be able to fulfill the requirements of a Moon base and energy to supply life support, maintenance, communications, and research, a combination of both nuclear and solar energy will be used in the first colonies.
   An alternative solution is studied in Europe by students to excavate a habitat in the ice-filled craters of the Moon.
  
  Section::::Structure.:Habitat.:Surface colonies.
   Many Mars mission concepts propose precursor missions to the moons of Mars, for example a sample return mission to the Mars moon Phobos – not quite Mars, but perhaps a convenient stepping stone to an eventual Martian surface mission. Lockheed Martin, as part of their "Stepping stones to Mars" project, called the "Red Rocks Project", proposed to explore Mars robotically from Deimos.
  
  Use of fuel produced from water resources on Phobos or Deimos has also been proposed.
  
  Section::::Precursor missions.:Mars sample return missions.
   Colonization of the inner Solar System
  
  Bodies in the inner Solar System have been considered for terraforming and space colonization. The main candidates for colonization in the inner Solar System are Mars and Venus. Other possible candidates for colonization include the Moon and even Mercury.
  
  Section::::Candidate locations.
  
  Section::::Candidate locations.:Moon.
  
  The short distance between the Earth and the Moon makes it a natural expansion after Earth. 
  
  A number of government space agencies have periodically floated lunar plans such as Russia (2014), China (2012) and the US have made plans in constructing the first lunar outpost.
   On January 31, 2013, the ESA working with Foster + Partners, tested a 3D-printed structure that could be constructed of lunar regolith for use as a Moon base.
  
  Section::::Energy.
  
  Section::::Energy.:Nuclear power.
   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.
   BULLET::::- 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.
  
  There are several disadvantages to the Moon as a colony site:
   All of the early human mission concepts to Mars as conceived by national governmental space programs—such as those being tentatively planned by NASA, Roscosmos and ESA—would not be direct precursors to colonization. They are intended solely as exploration missions, as the "Apollo" missions to the Moon were not planned to be sites of a permanent base.
  
  Colonization requires the establishment of permanent habitats that have potential for self-expansion and self-sustenance. Two early proposals for building habitats on Mars are the Mars Direct and the Semi-Direct concepts, advocated by Robert Zubrin, an advocate of the colonisation of Mars.
   Project Horizon was a 1959 study regarding the United States Army's plan to establish a fort on the Moon by 1967. Heinz-Hermann Koelle, a German rocket engineer of the Army Ballistic Missile Agency (ABMA) led the Project Horizon study. It was proposed that the first landing would be carried out by two "soldier-astronauts" in 1965 and that more construction workers would soon follow. It was posited that through numerous launches (61 Saturn Is and 88 Saturn C-2s), 245 tons of cargo could be transported to the outpost by 1966.
  
  Section::::Proposals.:Lunex Project.
   There are two reasons why the north pole and south pole of the Moon might be attractive locations for a human colony. First, there is evidence for the presence of water in some continuously shaded areas near the poles. Second, the Moon's axis of rotation is sufficiently close to being perpendicular to the ecliptic plane that the radius of the Moon's polar circles is less than 50 km. Power collection stations could therefore be plausibly located so that at least one is exposed to sunlight at all times, thus making it possible to power polar colonies almost exclusively with solar energy. Solar power would be unavailable only during a lunar eclipse, but these events are relatively brief and absolutely predictable. Any such colony would therefore require a reserve energy supply that could temporarily sustain a colony during lunar eclipses or in the event of any incident or malfunction affecting solar power collection. Hydrogen fuel cells would be ideal for this purpose, since the hydrogen needed could be sourced locally using the Moon's polar water and surplus solar power. Moreover, due to the Moon's uneven surface some sites have nearly continuous sunlight. For example, Malapert mountain, located near the Shackleton crater at the lunar south pole, offers several advantages as a site:
   Several techniques have changed the outlook on Mars exploration. The most powerful of which is in-situ resource utilization. Using hydrogen imported from Earth and carbon dioxide from the Martian atmosphere, the Sabatier reaction can be used to manufacture methane (for rocket propellant) and water (for drinking and for oxygen production through electrolysis). Another technique to reduce Earth-brought propellant requirements is aerobraking. Aerobraking involves skimming the upper layers of an atmosphere, over many passes, to slow a spacecraft down. It's a time-intensive process that shows most promise in slowing down cargo shipments of food and supplies. NASA's Constellation program does call for landing humans on Mars after a permanent base on the Moon is demonstrated, but details of the base architecture are far from established. It is likely that the first permanent settlement will consist of consecutive crews landing prefabricated habitat modules in the same location and linking them together to form a base.
   NASA chose to use a south-polar site for the lunar outpost reference design in the Exploration Systems Architecture Study chapter on lunar architecture.
   The concept of establishing a long-term human presence on the Moon can be traced back to the late 1950s. The Lunex Project, conceptualized in 1958, was a US Air Force plan to construct an underground Air Force Base on the Moon. On June 8, 1959, the US Army's Ballistic Missile Agency (ABMA) organized a task force called Project Horizon to assess the feasibility of constructing a military base on the Moon.
   Colonization of the Moon
  
  Colonization of the Moon is the proposed establishment of a permanent human community or robotic industries on the Moon.
  
  Discovery of lunar water at the lunar poles by Chandrayaan-1 in 2008-2009 has renewed interest in the Moon. Locating such a colony at one of the lunar poles would also avoid the problem of long lunar nights – about 354 hours long, a little more than two weeks – and allow the colony to take advantage of the continuous sunlight there for generating solar power.
   The solar energy converters need not be silicon solar panels. It may be more advantageous to use the larger temperature difference between Sun and shade to run heat engine generators. Concentrated sunlight could also be relayed via mirrors and used in Stirling engines or solar trough generators, or it could be used directly for lighting, agriculture and process heat. The focused heat might also be employed in materials processing to extract various elements from lunar surface materials.
  
  Section::::Energy.:Energy storage.
   Other locations considered for possible lunar outposts included the rim of Peary crater near the lunar north pole and the Malapert Mountain region on the rim of Malapert crater.
  
  The outpost design included:
  
  BULLET::::- Habitation modules
  
  BULLET::::- Solar power units
  
  BULLET::::- Unpressurized rovers
  
  BULLET::::- In-Situ Resource Utilization (ISRU) unit
  
  BULLET::::- Surface mobility carrier
  
  The outpost would have been supplied by a mixed crew and cargo Altair lander, capable of bringing four astronauts and a payload of six tons to the Moon's surface.
   In the same chapter, Zubrin decisively denounces and rejects suggestions that the Moon should be used as waypoint to Mars or as a 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. Antarctica or desert areas of Earth provide much better training grounds at lesser cost.
   NanoRacks, after finalizing its contract with NASA, and after winning NextSTEPs Phase II award, is now developing its concept Independence-1 (previously known as Ixion), the first 'outpost' in NanoRacks' Space Outpost Program, which would turn spent rocket tanks into a habitable living area, often known as a wet workshop.
  
  Planning and design for Lunar and Martian outposts is underway.
  
  Section::::Further reading.
   A lunar base built on the surface would need to be protected by improved radiation and micrometeoroid shielding. Building the lunar base inside a deep crater would provide at least partial shielding against radiation and micrometeoroids.
  
  Artificial magnetic fields have been proposed as a means to provide radiation shielding for long range deep space crewed missions, and it might be possible to use similar technology on a lunar colony. Some regions on the Moon possess strong local magnetic fields that might partially mitigate exposure to charged solar and galactic particles.
   In 1962, John DeNike and Stanley Zahn published their idea of a sub-surface base located at the Sea of Tranquility. This base would house a crew of 21, in modules placed four meters below the surface, which was believed to provide radiation shielding on par with Earth's atmosphere. DeNike and Zahn favored nuclear reactors for energy production, because they were more efficient than solar panels, and would also overcome the problems with the long lunar nights. For the life support system, an algae-based gas exchanger was proposed.
  
  Section::::Proposals.:Moon Village.
   In 1959, John S. Rinehart suggested that the safest design would be a structure that could "[float] in a stationary ocean of dust", since there were, at the time this concept was outlined, theories that there could be mile-deep dust oceans on the Moon. The proposed design consisted of a half-cylinder with half-domes at both ends, with a micrometeoroid shield placed above the base.
  
  Section::::Proposals.:NASA.
   Project Horizon proposed using a series of Saturn launches to pre-construct an outpost while in Earth orbit, with the intention of subsequently delivering and landing the completed assembly on the Moon. Additional Saturn launches each month would then ship supplies to the inhabitants.
   Lunex Project was a US Air Force plan for a crewed lunar landing prior to the Apollo Program in 1961. It envisaged a 21-person underground Air Force base on the Moon by 1968 at a total cost of $7.5 billion.
  
  Section::::Proposals.:Sub-surface base.
  
raw_presuppositions: The moon is a better place to colonise.
raw_corrections: Mars have more gravity and enough atmosphere to make insulation simpler.