Moon

The Moon is the only natural satellite of Earth.

Background
On July 16th, 1969, a team of the United States Air Force in a Virgo II lunar lander named Valiant 11 landed on the Moon, the first human beings to do so. On November 14th that year, a Virgo III lander named Valiant 12 landed on the Moon, and left the national flag of the United States on its surface before their departure.

In 2020, the Delta IX series of rockets were commissioned by the United States Space Administration, which underwent missions to the Moon, one of which was the 17-day Zeus 12. In 2052, the final manned mission to the Moon occurred, and during this, the flag left by the Valiant 12 was recovered and brought back to Earth, where it was put on display in Washington, D.C.'s Museum of Technology.

At an unknown point in history, a significant historical event occurred in the Mare Tranquillitatis (Sea of Tranquility) lunar mare, where the United States Armed forces were involved.

The Boulder Dome experimented with constructing settlements on the Moon.

Lunar phases
The phases of the moon The phases of the Moon is the shape of the directly sunlit portion of the Moon as viewed from Earth. The lunar phases gradually and cyclically change over the period of a synodic month (about 29.53 days), as the orbital positions of the Moon around Earth and of Earth around the Sun shift. In all first-person Fallouts, this is directly observable in the sky. Thankfully, despite wars on its surface and even the Great War, the Moon's elliptical orbit has been unaffected by humanity.

Each of the four "intermediate" lunar phases (see above) is around 7.4 days, but this varies slightly due to the elliptical shape of the Moon's orbit. Aside from some craters near the lunar poles, such as Shoemaker, all parts of the Moon see around 14.77 days of daylight, followed by 14.77 days of "night". The only phase not depicted in the picture about is the new moon which is completely dark.

Appearances
The moon appears in all Fallout games, but only really appears in the first-person perspective Fallout game. Significant mentions of the Moon appear in Fallout 3, Fallout: New Vegas, Fallout 4, and Van Buren.