Re: Performed as expected...
"The two lost Shuttles were destroyed by:"
A shitty design, necessitated by conflicting demands that made it big and ugly (a camel) and so dangerous that the USAF (whose demands drove the increase in size that forced it to be mounted to the tanks instead of riding on top of the stack) walked away from it very quickly.
Incident 1 wouldn't have been fatal if the orbiter was on top and incident 2 wouldn't have even happened.
The primary reason Buran only made one flight was because the Soviet space engineers refused point blank to allow humans to fly in it. They built it to prove they could and to understand its purposes (something capable of bringing large items down has immense military tactical value - it can be used to attack satellites) but having done that they wanted nothing further to do with it (The Buran designers wanted to put the thing on top of the stack, but were overruled because it would take too long to develop - after the first flight it was decided that the cost of redesigning to put it on top so it could safely carry humans was too high for any possible benefit inherent in having a "shuttleski")