When Starfleet's Leonov class research ships prematurely reached the end of their useful lives, Starfleet found itself with a sudden shortage of science vessels suitable to carry out the exploration and research work mandated by its charter. While the new Verne class exploration vessels had already been approved, the first of these ships was not due to be completed for some years, and it was impractical to refit the remaining Leonov class again. While some of the research could be done by other ships in the fleet, Starfleet desperately needed vessels with dedicated scientific capacity, and building an interim stop-gap class from scratch was impractical.
Starfleet decided that the best solution was a conversion of an existing class of ship with the range and capacities required. As a result, six Glenrowan class frigates were refitted as science vessels to meet Starfleet's demands after the type was superseded by the Balmoral class. The main changes were removal of most of the weaponry, replacement of the original warp nacelles, expanded interior capacity (with a reduction in complement from 200 to 145, as labs were added and the accommodation was upgraded from military to civilian spec), as well as the addition of the main sensor array mounted on the engineering section. These ships were re-designated as Bayern class science vessels.