Moon
Before the horrific Astral Gate incident the Moon was the first a primary home to humanity outside of the Earth, though planned terraforming of Mars and Venus had already begun. After the incident the Moon was so unstable that those lucky enough to survive the explosions left for other colonies and space stations. In the decades since, even though the Moon remains unstable, some have returned in attempts to monitor the world. No longer a home to civilians, the Moon is only inhabited by a handful of scientists and meteor forecasters at any given time.