Moon Moon is a "Island 1" type colony, also known as the Lost Colony, home to a primitive group of space dwellers. Seen in Mobile Suit Gundam ZZ.
Moon Moon is an old space colony built over 100 years ago as a development base for the construction of Side 1. It was abandoned after Side 1 was completed, however, there were those who secretly remained and illegal immigrants who continued to live there. The residents refused contact with the outside world and led a unique lifestyle that regressed to a hunter-gatherer society. The Light Tribe preaches the ideals of "abandoning technology and coexisting with nature" and there is an internal dispute to spread these teachings to other space colonies. The colony's outer wall is thinner than in modern space colonies, providing insufficient radiation protection and resulting in a high mortality rate among the population.
In U.C.0092, the Gundam Mk-IV G-Doors' head and Psycho Plates collided with Moon Moon's outer wall, causing the environment system to fail. The Light Tribe dispatched a spacecraft to request the Colony Corporation for repairs, however the spacecraft is lost during a battle between Neo Zeon's Atlante 3 and a Londo Bell squad.
In Mobile Suit Crossbone Gundam: Dust, Moon Moon residents returned to Earth after the Zancare War of U.C.0153 and settled there. However, Earth's natural environment proved harsh for the spacenoids and they withdrew to the underwater city Ryuguujo, which had an environment similar to a space colony. In U.C.0169 there is a dispute between the ruling class who wish to return to space with assistance from the Jupiter Republic and the "Surface Alliance" who want to adapt and remain on Earth.