> but it wasn't thought of or acknowledged by NASA as being risky until very late in its lifecycle.

They understood it to be extremely risky immediately. They understood the ice issue early on as evidenced by the fact that they completely changed the coating on the external fuel tank to try to compensate for it. They also added ice bridges and other features to the launch pad to try to diminish the risk. They also planned for in orbit heat shield tile repair. They specifically chose the glue to be compatible with total vacuum conditions so they could actually detach and rebond a whole tile if necessary. They developed a complicated and, unfortunately wrong, computer model to estimate the damage potential of ice strikes to the heat shield tiles. What they _finally_ came to understand was that you just have to swing the arm out on orbit and take high resolution pictures of the vehicle to properly assess it's condition.

NASA was and always is very bad at calculating systemic risk. They have the right people developing risk profiles for individual components but they've never had the understanding at the management level of how to assess them as a complete vehicle in the context of any given mission.

> Roughly 3x riskier than the shuttle.

The huge advantage they now have is a capable launch escape system which can possibly jettison them away from the rocket should any issues arise during ascent. That was the one thing the shuttle could not possibly integrate.

On the other hand they could take a far larger crew to orbit and maintain them comfortably for several weeks during the mission. The "space bus" generated a healthy 21kW from it's fuel cells and created so much water that you had to periodically dump it overboard. This was a blessing for the ISS because you could bag up all that excess water and transfer it for long term use.

Anyways.. as you can tell.. I just really loved the shuttle. It was a great vehicle that was ultimately too exceedingly tricky to manage safely.