Star Trek: 10 Secrets About The USS Discovery-A You Need To Know
1. Ticking the Register(y)
Aside from getting a nice new tattooed registry which acts to "hide" the Discovery's real origins in the 23rd Century and play havoc with the canon of Calypso, under to hood the Crossfield Class refit is much more than detached nacelles.
It's also worth a quick compare to Picard. In that show the USS Titan underwent such an extensive refit that it became a brand new ship and gained the "A" suffix. This is mirrored in Discovery six centuries later where the lead ship also undergoes significant changes and gains a dash and a letter after its registry. In fact this marks only the sixth starship in 60 years of the franchise to extend its registry and lineage with a letter. One that fans will immediately recall is the USS Voyager-A and the USS Voyager-B from Prodigy and Picard. There's the Titan as well as a certain USS Enterprise. All four of these ships have gained the "A" with only two confirmed as having crossed off letters to J.
There's perhaps the lesser known USS Excalibur seen in Federation HQ during the 32nd Century with registry NCC-1664-M and the seed ship USS Tikhov which also adds an "M" to the NCC-1067 registry. Discovery has a long way to go to catch up and they have a few centuries of head start.