Luna

The Moon is Earth's only natural satellite. At about one-quarter the diameter of Earth (comparable to the width of Australia), it is the largest natural satellite in the Solar System relative to the size of a major planet, the fifth largest satellite in the Solar System overall, and larger than any known dwarf planet.

The Moon is a planetary-mass object that formed a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's (0.1654 g); Jupiter's moon Io is the only satellite in the Solar System known to have a higher surface gravity and density.

At the time of the Second Extrasolar War, Earth's Moon was used as an official UCA Space Port, that was widely responsible for transporting supplies to and from the Alpha Centauri System.