RWE #66 said:

“Whatever the reason for the deletion of the penaids and the change in the aft section of the RV, it was probably quite mundane – like cost. Or maybe making the aft end of the RV spherical would have made it too hard to handle for the crews installing it.”

I’m sure you’re right. Also group think along the lines of “too many cooks spoiling the broth” can lead to weird decisions. In a bungled aerospace project like X-33 it is typical that every single person is intelligent, competent and devoted to the project. However when group-think cuts in (the design team gets too large or is poorly managed), their collective IQ drops to the lowest common denominator. No doubt Norman Augustine has some law describing this.