Operation: Gray Ghost (also known as Project: Grey Ghost) was the codename of a Starfleet Intelligence deep-space survey mission into Romulan space.
After learning of the Klingon Sector Group of Starfleet Intelligence making preparations for their Operation: Dixie mission in 2274, the rival Romulan Sector Group began planning a similar mission, Operation: Gray Ghost, which launched ahead of schedule in 2276.
In 2285 the project was complete and deemed to be an unqualified success. Starfleet gained important new information on the Romulan Star Empire. (FASA RPG module: Star Trek IV Sourcebook Update)