In 2266, the station was under the command of Commodore Krinsky, and was in the process of being decommissioned, when dilithium deposits were found on the planet below. Klingon infiltrators killed Krinsky, and the IKS D'k Tahg arrived to take the dilithium. The crews of the USS Enterprise and USS Constellation battled Klingons on the station, and eventually expelled them. (TOS novels: River of Blood, Seeds of Rage)
In 2287, the station was commanded by a reptilian Starfleet Captain when the USS Enterprise-A picked up Ambassador Palmer there. Palmer berated both the station's commander and Captain James T. Kirk for the fact that the ship was an hour late. (TOS comics: "The Return!", "The Sentence")
- At this point Starbase 42 appears to be the same style of station as the Earth Orbital Office Complex seen in Star Trek: The Motion Picture.
- In this novel, the station is described as brand new. It can be conjectured that either the old Starbase 42 had been heavily refurbished, or else Starfleet had given the designation to an entirely new facility.
- It is never directly stated that Starbase 42 orbits Casmus III, but given that the Enterprise-A is headed for that planet in "The Return!" and arrives at the starbase in "The Sentence", it seems a reasonable assumption.