2270 (Columbia)

Stardate 6063.4: A mysterious being threatens to destroy the Enterprise if the crew is unable to solve an ancient puzzle. (TAS 21: "How Sharper Than a Serpent's Tooth")
Stardate 6334.1: Spock contracts a fatal illness, and the cure can only be found with dangerous Orion pirates. (TAS 19: "The Pirates of Orion")
Stardate 6770.3: An unusual spaceship pulls the Enterprise into a "negative universe" where time seems to flow backwards. (TAS 22: "The Counter-Clock Incident")
Stardate 7403.6: The Enterprise crew is taken captive by a race of primitives on a newly discovered planet. (TAS 17: "Bem")

The U.S.S. Enterprise NCC-1701 ends its Five Year Mission under Captain James T. Kirk, and enters spacedock for an extensive refit. (VOY 265: "Q2"; Star Trek: The Motion Picture)