Ever since it appeared on display in the Enterprise recreation room of Star Trek: The Motion Picture, fans have wondered about the mysterious “ring ship” which was supposed to be a predecessor to the familiar Enterprise. It did not reappear until Star Trek: Enterprise, when a similar painting hung on the wall of the 602 Club in the episode “First Flight.” The same painting appears again in the episode “Home”.
No further canon information is available about the design, yet the book Star Trek Maps (1980) describes it as a “starliner.” Supposedly they were “Earth’s first attempts at manned interstellar probes” launched during the 2050s. Only one, the UESP Enterprise, reached its destination — the sun-like binary pair of Alpha Centauri — before they were overtaken by new faster-than-light spacecraft. The book said the starliners were 120 meters long and carried a crew of 35.
Rick Sternbach’s Star Trek Spaceflight Chronology (1979) features a similar design and calls it the Declaration class. According to the Chronology, this vessel was in service between the years 2123 and 2165 and carried a complement of 950. That must be a gross exaggeration, though. The original Enterprise didn’t carry half that number!
The “ring ship” was in fact based on an early Matt Jefferies design for the original Enterprise. After Gene Roddenberry rejected Jefferies’ first proposal, which he felt was too much like a flying saucer, the latter came up with the ring ship. Roddenberry rejected this design too, which led to Jefferies to develop the ship we now know as the Constitution class. (See Designing the First Enterprise.)