In 2364, the location of the Starbase 4077 facilities was labeled on the Starbase Ops Status Sol Sector star chart. (TNG: "Conspiracy" , okudagram) This starbase was only mentioned in writing. The number 4077 was an in-joke reference to M*A*S*H. According to the Star Trek Encyclopedia (3rd ed., p. 466) , after "The Neutral Zone" had aired, it was decided that the starbase numbers shouldn't go much higher than 500.