On it are 300 men and women from all the nations of Earth, originally based there to man an early-warning system and to repel invaders. Now they are Earth's sole survivors, on a quest for a new planet compatible with their needs. Ironically, they are considered the invaders, by inhabitants of other planets. All sets, of course, are futuristic. Additional exteriors include domestic and industrial structures, armament and observation equipment.
Interiors are highly sophisticated and complex representations of space technology.
The moon is 2,160 miles in diameter. Control of it as it speeds through space is maintained within a compound about twenty miles square and protected by an elaborate security ring of fences, photo electric fields and domes. Only top security personnel are permitted within these boundaries, and fewer still within the Commander's Control Sector. Inside the general compound there is a stratofield, with hangars for various lunar craft. There is also a circular metal disc about 30 yards in diameter.