The Federation Spaceflight Chronology was a series of technical manuals and in-universe historical documents by Richard E. Mandel.
The FSC attempted to synthesize chronicles of Federation history from disparate fanon sources, such as FASA, Last Unicorn Games, pro-novels and comic books.
The FSC asserts that 2261-2265 was the timeframe for James T. Kirk's (first) five-year mission as commanding officer of the USS Enterprise (derived from the Chuck Graham/Geoffrey Mandel timeline created in 1974), as well as uses the dates for the robotic and crewed Sol system exploration missions from the Stan and Fred Goldstein-authored (with illustrations by Rick Sternbach) Spaceflight Chronology (published in 1980).