$4.1B, DOUBLE that number and you might be close. Same BS used in the 70’s to convince Congress that the Shuttle was Cheap and Quickly turned for next launch. I think their estimate was off by a factor of 4 and Quick turn ended up being just under a year for only the last launch. Lots of issues with the Tiles staying on.
Those tiles were cool. My dad was a programmer that built the programs for a lot of the tiles. Cutting each tile had to be programmed individually, and there were like 30,000 tiles. If it was off by more than 1/100 of an inch the tile was rejected. We used to have 3 of them in the house. For his work on the project, we were invited to the rollout of the Columbia, and I actually got to go onboard. They were held don’t to shuttle with the equivalent of glass velcro. Dad died several years back, and now I live in Florida near Space Coast. I will be going out to the beach to watch the launch tomorrow.