The Starfleet Deep Space Exploratory Corps was a department within Starfleet.
This corps was responsible for the charting and exploring of space in and out of Federation territory. The movement of personnel in and out of this corps was governed by the Starfleet Transfer Regulations. Promotion in the corps was considered for eligibility by the Deep Space Corps Selection Board. The Starfleet crewmembers of the USS Enterprise-D were in this corps. (TNG: "The Measure Of A Man", okudagram)