Star Trek: 10 Secrets Of Deep Space 9 You Need To Know
3. The Largest Refinery In Space
Often forgotten due to its role as the Federation and Bajor's first line of defense against the Dominion, Deep Space 9 began its life as an ore refinery in orbit of Bajor. Under the operation of the Cardassians, DS9 AKA Terok Nor refined up to 20,000 tons of ore a day thanks to the Bajoran slave workforce – a particularly grim part of Star Trek: Deep Space Nine's backstory.
The ore processing center on the station only featured in a handful of episodes like "Civil Defense" and "Crossover", but according to Rick Sternbach and Doug Drexler's Star Trek: Deep Space Nine Technical Manual, much of Deep Space 9's interior was dedicated to processing minerals transported to the station from Bajor. Along with the usual corridor network and turbolift system, DS9 possessed a series of channels running throughout the inner structure whose function were to convey the valuable uridium ore.
According to the aforementioned Technical Manual, while it wasn't the largest space station known to the Federation (it was dwarfed by Earth Spacedock), DS9 was the largest ore processing facility in space.