I was getting ready to do signage for the secondary hull and nacelles earlier and I decided to got to Memory Alpha, Memory Beta and the Expanded Universe Wiki (AKA, the main Trek Wikis) and check for ships named Challenger. It turns out there are a lot. Two are canon but there are also about a half dozen noncanon Challengers. So, I decided that this necessitated a name and registry change (I wasn’t that warm and fuzzy about NCC-7200 anyway.) So, I redid the saucer name and number to USS Hipparchus NCC-8957. There’s only one ship in all of Trek named Hipparchus and it’s noncanon anyway. It’s a transport (which is kinda odd, give that Hipparchus is an ancient scientist) that appears on the list of Ptolemy-class transports in the old Star Fleet Technical Manual from ’75.
I also added some more windows and other knickknacks inspired by the 1701-A to the saucer section. Also, I changed the nacelles. The old ones were too large, giving the ship a really unbalanced look.