Io

Io was the innermost moon of Jupiter.

After the 32nd century, Io was terraformed, and became the headquarters of the Galactic Federation during its reign. (PROSE: Legacy) Lord Izlyr planned on taking Princess Lixgaar of New Mars to Federation headquarters on Io until New Mars was safe enough for her to return. (AUDIO: The Prisoner of Peladon)

Calypso Jonze, a bounty hunter native to the 51st century, came from Io. (AUDIO: The Lovecraft Invasion)

Melanie Bush thought Io looked like a cheese and tomato pizza. (PROSE: Uranus)

The terraformed Io was one of the 700 Wonders of the Universe. (PROSE: Legacy)

Behind the scenes
In the real world, it is not the innermost moon, as more inner moons have been discovered.