The new frontier will cost us lives. That is the nature of frontiers. But the only ship that is safe is the one that stays in harbor, and that ship accomplishes nothing.
BTW, I wonder how many of the folks who will scream their regrets at the age of the shuttles are the same people who can't see a reason that we need another $40 billion to fight a world war, or understand why we need to replace a KC-135 fleet that is about to hit 50 years of operation.
Don't confuse the absolute necessity of "high flight" with justification of the design and management of STS.
I agree that 1/75 is a probable failure rate.
The problem is that the managers have been ordered to design and operate a program that assumes a 1/100000 failure rate.
Using your number, after 300 flights we would have no more orbiters.
Where is the assembly line? What design work is going on for the replacement vehicles? What are the budget assumptions to support a program with a 1/75 failure rate? How are the flight test personnel being selected? Is the use of civilian mission specialists consistent with a failure rate of 1/75?
Nothing-absolutely nothing-about the shuttle program is consistent with a 1/75 failure rate. Except reality.