The Brick Moon was an artificial satellite space station where the Earth should have been in the West Gap universe. It was made out of pre-fabricated sections of brick and concrete using troll labour. The Galileo was launched from it.
It is described as the Houston of the Gap, with its constant comms presence for space-travellers and a place where some zero gravity research can be done.
The station is described as a cluster of spheres, the whole about two hundred feet across, with each component being lettered A to K.