Tango Sierra was a massive spacedock, and sister station to the Earth Spacedock. This station was located in or near to an asteroid field. Tango Sierra was operational in the late 23rd century. In an alternate reality, the USS Reliant, along with the USS Enterprise-A and an unnamed Excelsior-class starship, were seen on approach vectors to this spacedock. (ST calendar: Ships of the Line 2012)