Seems strange to me that Earth's first Warp 5 ship NX-01 would not have a successor for more than 80+ years until the Constitution class 1701 is built. If you go by the extended Enterprise novel series she is decommissioned in 2161. And the Constitution class 1701 Enterprise doesn't start her first 5yr mission until 2245. Has there ever been any mention of another class ship named Enterprise that existed between NX-01 and 1701?