The first UNSS Arcturus was a DY-500-class vessel that made the first Earth-Saturn voyage under the command of Colonel Shaun Geoffrey Christopher. Arcturus, with a crew of 40, was launched in 2018 and entered orbit of Titan on 31 March 2025. (Col. Christopher and his expedition are mentioned in TOS: "Tomorrow is Yesterday")
Arcturus and its small crew spent several months of exploring the surface and planting sensor packages that would enable information on Titan to be sent back to Earth for many years afterwards. The ship returned to Earth orbit by mid-2031. Sadly, Arcturus was one of many space vessels destroyed in Earth orbit during Col. Green's War in 2035.
The Bonaventure-class explorer UNSS Arcturus, the second starship named, was a mainstay of the Earth-Alpha Centauri patrol sector, first established in the 2090s. Standard complement was 45 officers and crew.
- The continuity of Expanding the Oecumene refers to this patrol sector as Sector Zero.
Arcturus was retasked as a commercial carrier (thus, it changed from “UNSS” to “SS”) in 2110 for use by scientific expeditions. Its modular design made it ideal for such tasks.
In the late 2120s, Arcturus conveyed a team from the American Continent Institute and surveyed red dwarf stars within a 5-parsec sphere of the Sol system. The team, led by Esteban Velasco, identified heretofore undiscovered reserves of topaline and pergium on the fifth planet of Wolf 359. (Star Trek: Shadowstar Station: "Esteban")
Eight years after this survey, Arcturus was lost in the so-called "Delta Triangle" region. ("The USS Arcturus in History")
A modified Daedalus-class cruiser UNSS Arcturus -- carrying more powerful lasers and a prototype accelerator cannon -- distinguished itself at the battles of Alpha Trianguli and Nu Chalcedonis against Romulan forces during the Earth-Romulan War. ("The USS Arcturus in History")
- Though not mentioned in the original article, Arcturus must have been part of one of the three Earth Starfleet squadrons that made up the 12th Strike Wing at Nu Chalcedonis, per the FASA RPG module The Romulan War.