The USS Clarke (NCC-100) was the prototype and lead ship of the Clarke-class diplomatic clippers. It was on active duty in Starfleet during at least the last quarter of the 23rd century. (Starfleet Dynamics) A cutter named USS Clarke greeted USS Enterprise on its return to the Sol system, following a test of the inversion drive, in 2275. (TOS novel: The Wounded Sky) It is not known if the two Clarkes were actually the same vessel.