In the mirror universe, Luna was the only natural satellite of Earth in the Sol System. On one occasion prior to 2155, the Terran Empire landed on Luna, planting a flag on its surface to signify this achievement. (ENT episode: "In a Mirror, Darkly") In 2295, the Moon was conquered by the Klingon-Cardassian Alliance following the fall of the Terran Empire, the successor state of the Terran Republic.