The initial moonbase would need to be self-sufficient. It would need to be designed for protection against extreme temperatures and high radiation levels on the Moon. The base life support system would be entirely closed. All waste gases, liquids, and solids are recycled, and there is a food production facility including a greenhouse.

NASA developed an updated concept of an initial lunar outpost in early 2009. The first structures are currently expected to be inflatable.

With certain sites near polar heights receiving sunlight more than 80% of the time, general power requirements could be satisfied by solar energy. At a more equatorial location, for the night period of 14.75 days, when the solar power would not function and for lunar manufacturing, fuel cells or the installation of a nuclear power generating station would probably be required.

The initial moonbase could be constructed by linking together metal habitat canisters and inflatable structures. For radiation protection, these units would need to be buried under a layer of lunar regolith (soil) using excavation equipment. This video shows a lunar bulldozer under development in early 2008. The basic infrastructure will include life-support structures and climate control system, a solar power plant, an oxygen generator plant, a lunar ice processing plant, a greenhouse to produce food, plus the excavation of a Lunar spaceport, and the preparation of a supply processing and storage area.

A key requirement will be water. The most likely source of water will be ice on the dark bottoms of craters near the poles. Shipping water to the Moon for use by humans would be extremely expensive ($2,000 to $20,000 per kg).

In addition, extensive exploration of the lunar environment will be made for nitrogen and carbon sources necessary for food production. Although present in lunar soil, the amounts are too small to be easily extracted. Carbon could be found in meteorites and nitrogen may be found locked in gas pockets under the surface. These elements must be found if the Lunar Station is to become truly self-sufficient.

Underground Approach

Lava tube entrance on Earth

Building the lunar colony underground would give protection from radiation and micrometeoroids. Even before the initial base is operating, the area around the site and elsewhere will be explored for the presence of lava tubes (drained conduits of underground lava rivers) for future underground habitation. Lava tubes could provide an environment naturally sheltered from radiation, thermal extremes, and micrometeoroid impact. Even more important at the early stage of human lunar settlement, there use would be less expensive than excavation of manmade tunnels.

Lava tubes located on earth can be quite large. As an alternative to excavating, similar tubes on the moon (with surface irregularities removed) could provide sufficient space for base activity during the early years of a lunar colony. Evidence pointing to the existence of lava tubes on the Moon does exist, but needs to be confirmed through further exploration. Confirmed tubes would be mapped and their existence could facilitate decisions on moonbase location.

Cracks in the tube roofs may prevent them from being made air-tight, but they could house thin-skinned inflatable structures. Another approach would be the "cured in place" technology used on earth to rehabilitate old drainage pipes. They are re-lined with a cooled, resin filled liner which hardens when heated. A similar approach could provide an air tight lining for lunar lava tubes or manmade tunnels. Unlined tubes could serve as unpressurized hangars or garages.

The possibility of excavating tunnels into the sides of the craters would be a longer term solution. The construction of such a permanent base would be complex. One of the first machines from Earth might be a remote controlled boring machine to excavate living quarters. 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. Air tight flexible lining or inflatable self-sealing fabric habitats would be required to retain air.

Cities

Once lunar settlement has passed beyond the initial colony stage to permanent cities, construction of labyrinthine underground corridors and greater voids in the rocky crust becomes possible. Advances in technology would need to produce fast tunnel cutters that melt through the lunar rock and form a structurally sound finished surface. The rock overhead shields the inhabitants from radiation, changes in temperature during the day/night cycle and virtually all meteors. As a safety measure, airlocks could separate neighborhoods. Parks and gardens could be created in excavated voids using artificial light or beneath transparent domes roofing craters. Agriculture produce would be grown hydroponically during the lunar day in excavated channels covered with a transparent skylight that could be covered with an insulated moveable roof during the lunar night.

The crater walls would be excellent places to locate windows, allowing the inhabitants to look out on the actual lunar surface. The actual windows would be set back within the wall to eliminate penetration by micrometeors. The rock overhang could provide radiation and meteor protection.

Domed adjacent craters could be parks containing trees growing to great size and height in the weak gravity. With the moon's light gravity, it would be feasible for the domes to be constructed of material able to shield against small meteors and radiation.

Within most of the city, outside views would be video perspectives of lunar or earthly scenes displayed on walls. Power would most likely be generated by fission or fusion energy or the sun. The latter source would come from solar cells located on heights at the lunar poles able to catch the maximum period of daylight. Power lines laid in trenches cut in the lunar surface would connect the solar power sources to the lunar cities. Two hundred years in the future, the lunar cities would be connected by underground tubes through which trains would travel.

Given the relatively light gravity compared to earth, exercise for the able bodied would be mandatory for physical health. Should long-term presence in such a light gravity be ill advised (persons would weigh less than one fifth of their earth weight), periodic stays on earth may be required.