A ship of the line ,the Copperfield class served as the initial successor to the entire NX class (both refits, Franklin variants, and basic Warp 5 designs). This class had a cruising speed of Warp 5 and an emergency speed of Warp 6.8. This warp frame could theoretically reach Warp 7.1, however this would lead the risk of exposing the crew to warp field radiation, and or vaporizing the crew itself (this was usually only achievable and "safe" through the use of a modified external deflector dish array). This class would have served from the late 2190s to the early 2270s with the introduction of the refit Constitution class and other TMP era ships. The final ship of this class would have been the NCC-1885 U.S.S. Tannen, which was constructed on Earth in 2255, and would be decomissioned in 2285. While the overall design of this ship was inspired by the Franklin variant of the NX class, it would have a multitude of upgrades, such as true phasers turrets, a human rated transporter, and the capability to enter, land, and take off from an atmosphere.