Moon was thought to have no atmosphere until recently. Discovery of existence of water on the surface of moon have led to the idea that moon indeed has an atmosphere. Presence of minute amounts of ice was detected by the satellites launched in the lunar orbit. If there is ice, then there must be water vapor as all regions of moon are exposed to sunlight. So any ice exposed to sunlight would be lost. The only possible way for the existence of ice would be in permanently shadowed regions which exist in the bottom of deep craters near the moon’s South Pole. Within these regions the temperature would never rise above -280 degrees Fahrenheit which allows the existence of ice for billions of years.
Compared to that of earth, moon has a very minimal amount of air. Atmospheric density is very much negligible compared to that of earth. It’s atmosphere does have unusual gases like sodium and potassium that are not found in earth’s atmosphere. There are also very small amounts of atoms and molecules including helium, argon, and neon, traces of ammonia, methane and carbon dioxide.
We know that the surface of moon is unprotected from cosmic rays. There is also some impact of solar winds on collision with the atoms of moon’s atmosphere. The continuous bombardment of meteors and interstellar charged particles results in the formation of lunar soil due to the mechanical disintegration of basaltic rock. The lunar soil does not contain any organic content like that of earth.
Presence of ice and properties of lunar soil are some of the most highly valued piece of information for the scientists who study if these elements could power their future missions.