Survey Four was a human base established on Earth's Moon to search for minerals and ores to ease the shortage on Earth in the 30th century. It was funded by the big corporations on Earth.
- Its name implies there were at least three other bases on the Moon during this period.
The base was divided into at least eight sectors spread around a central control room and living area, each split by airlocks to accommodate for occasional "moonquakes". The entire base was standardised to Earth level gravity which could be altered between sectors.
The base used three robotic drills to dig down through the Moon's crust. The path left by a drill could be almost immediately sealed and given a breathable atmosphere. An elevator pod connected the control room with a natural fissure, from which the drills were initially launched. A "maze" of tunnels criss-crossed the elevator shafts which all lead back to the living area near the surface.
Force bubbles could be extruded onto the surface at a moment's notice to accommodate surface work or landing craft. These provided a breathable atmosphere but were not able to provide artificial gravity.
The base was powered by a generator in a small room near the back of the living quarters. A backup generator was kept in case the main one malfunctioned. which it was prone to do.
Survey Four was staffed by a small team; Professor Dollund, the leader of the expedition; Clinton Seymour, the chief technician; Roberta Goodman, an archaeologist assigned by the Bureau of Alien Technology; Henderson, the chief mining engineer and Lisa Summerton, a junior engineer.
After digging a considerable distance, the drills came across a cavern that housed the Eternity Crystal, the presence of which animated the dust in and around Survey Four. After getting in touch with Moonport Five, the base was evacuated. (TDL: The Dust of Ages)