It has recently become apparent, by the collision of L-cross into the Luna’s South Pole, that Luna also has plenty of water in the form of ice. The discovery of spectral shift which identified water led scientist renew their enthusiasm for a lunar outpost. Analysis of water in a mostly pristine environment might have recorded events of our solar system shortly after Luna’s formation. A notable atmosphere must be created before terraforming can begin, as well as the addition of extra water via comets. However, the moon is too small to hold an atmosphere for very long so putting a global giant air dome or replenishing the atmosphere as needed. Days and nights would last about 2 weeks, so going outside would probably be restricted to sunrise and sunset (which would last a while) on Luna.
- Equatorial surface gravity: 1.622 m/s^2
- Escape velocity: 2.38 km/s
- Surface temperature: Varies
Because of its low gravity, lack of a magnetic field, and proximity to the sun, it is very problematic for the Moon to hold on to a dense atmosphere; nitrogen, which is the main "buffer gas" on Earth, would be blown away by the solar wind.
The only way to create a stable atmosphere is to fill it with heavy inert gases (like xenon and krypton). As these gases only exist in trace amounts, the only efficient way to create them in large amounts is by nuclear fission, which is beyond our current technology. Because of its proximity to the sun, greenhouse gases would not be necessary in large amounts. The ultraviolet radiation would be very strong, so at least small amounts of oxygen would be needed to form an ozone layer.
The moon may have no water, and if it does it will have very little. The only way to increase the amount of water is to redirect small, icy asteroids on a collision course with the Moon, which is also possible with current technology - on paper - but has not been demonstrated in the field. The transfer of momentum from these ice asteroids, or comets, as they collide into the moon, could, in theory, be used to speed up the rotation of the moon, which would reduce diurnal temperature variations further shaping the moon towards a more Earth-like environment.
However, moon rock appears to have oxygen and hydrogen , so it may be possible to refine that, to make water and oxygen, potentially speeding up a terraforming or pre-terraforming colonization process.