Colonization of The Moon - Advantages and Disadvantages

Advantages and Disadvantages

For more details on this topic, see space colonization.

Placing a colony on a natural body would provide an ample source of material for construction and other uses in space, including 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 propelant 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, however, 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. This proximity has several benefits:

• A lunar base could be a site for launching rockets with locally-manufactured fuel to distant planets such as Mars. Launching rockets from the Moon would be easier than from Earth because the Moon's gravity is lower, requiring a lower escape velocity. A lower escape velocity would require less propellant, but there is no guarantee that less propellant would cost less money than that required to launch from Earth.
• The energy required to send objects from Earth to the Moon is lower than for most other bodies.
• Transit time is short. The Apollo astronauts made the trip in three days and future technologies could improve on this time.
• The short transit time would also allow emergency supplies to quickly reach a Moon colony from Earth, or allow a human crew to evacuate relatively quickly from the Moon to Earth in case of emergency. This could be an important consideration when establishing the first human colony.

Wikiversity has learning materials about Lunar Boom Town

• If the Moon were colonized then it could be tested if humans can survive in low gravity. Those results could be utilized for a viable Mars colony as well.
• The round trip communication delay to Earth is less than three seconds, allowing near-normal voice and video conversation, and allowing some kinds of remote control of machines from Earth that are not possible for any other celestial body. The delay for other solar system bodies is minutes or hours; for example, round trip communication time between Earth and Mars ranges from about eight minutes to about forty minutes. This again would be of particular value in an early colony, where life-threatening problems requiring Earth's assistance could occur.
• On the Lunar near side, the Earth appears large and is always visible as an object 60 times brighter than the Moon appears from Earth, unlike more distant locations where the Earth would be seen merely as a star-like object, much as the planets appear from Earth. As a result, a Lunar colony might feel less remote to humans living there.
• A Lunar base would provide an excellent site for any kind of observatory. In the near-vacuum of the Moon's atmosphere, there is practically no atmospheric diffraction. Observations could be made continuously, provided that during the lunar day an optical telescope would be shaded from the Sun and from surrounding glare, and that it would not be pointed too close to the Sun or to the horizon. It would be possible to maintain constant observations on a specific target with a few such observatories at different longitudes. The Moon's geological inactivity and its infrastructural remoteness bring about an unusual mechanical calmness, which would be advantageous particularly regarding the erection of interferometric telescopes, even at relatively high frequencies such as visible light. NASA scientists have done developmental work toward manufacturing telescope mirrors using lunar material. 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.
• 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:

• The long lunar night would impede reliance on solar power and require a colony to be designed that could withstand large temperature extremes. 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 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 mission of the Lunar Crater Observation and Sensing Satellite (LCROSS) proved in 2009 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 people have ever mined. Other volatiles containing carbon and nitrogen were found in the same cold trap as ice. 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 the colony's rate of growth and keep it dependent on imports. The transportation cost of importing volatiles from Earth could be reduced by constructing the upper stage of supply ships using materials high in volatiles, such as carbon fiber and plastics. 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. However, these possibilities are dependent on complicated and expensive resource utilization from the mid to outer solar system, which is not likely to become available to a Moon colony for a significant period of time.
• It is uncertain whether the low (one-sixth g) gravity on the Moon is strong enough to prevent detrimental effects to human health in the long term. Exposure to weightlessness over month-long periods has been demonstrated to cause deterioration of physiological systems, such as loss of bone and muscle mass and a depressed immune system. Similar effects could occur in a low-gravity environment, although virtually all research into the health effects of low gravity has been limited to zero gravity.
• 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. 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 colony), raising the issues of the health threat from cosmic rays and the risk of proton exposure from the solar wind, especially since two-thirds of the Moon's orbit is outside the protection of the Earth's magnetosphere. Lunar rubble can protect living quarters from cosmic rays. 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.
• The lack of an atmosphere increases the chances of the colony being hit by meteor. Even small pebbles and dust (micrometeoroids) have the potential to damage or destroy insufficiently protected structures.
• Moon dust is an extremely abrasive glassy substance formed by micrometeorites and unrounded due to the lack of weathering. It sticks to everything and can damage equipment, and it may be toxic.
• 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, nitrogen-poor soil, and lack of insects for pollination. Due to the lack of any atmosphere 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 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.
• One of the less obvious difficulties lies not with the Moon itself but rather with the political and national interests of the nations engaged in colonization. Assuming that colonization efforts were able to overcome the difficulties outlined above – there would likely be issues regarding the rights of nations and their colonies to exploit resources on the lunar surface, to stake territorial claims and other issues of sovereignty which would have to be agreed upon before one or more nations established a permanent presence on the moon. The ongoing negotiations and debate regarding the Antarctic is a good case study for prospective lunar colonization efforts in that it highlights the numerous pitfalls of developing/inhabiting a location that is subject to the claims of more than one sovereign nation.