*From:* "Greg D. Moore \(Strider\)"
*Date:* Tue, 16 Dec 2008 23:50:54 -0500

"M" wrote in message

m...

What piqued my interest in that document was the reliability ratings
for manned spaceflight. I have no idea how they figured tehat the
Ares
designs were safer than the Delta or Atlas.



Oh that's easy. It's called wishful thinking.

Seriously, they do a lot of stuff like fault-tree analysis. The
problem is that's only as good as your fault-tree.

For example, ice puncturing the RCC on the shuttle wasn't
considered possible, so wasn't in any fault-tree (as far as I know).

The reality is while you can do a lot of good analysis, until
you've flown any craft a few hundred times, it's still a lot of
guess work.

So, we're going to take the shuttle, with a database of 100+
flights (and 200+ successful SRB flights) and replace it with a
"safer" vehicle with an all new SRB design. Somehow a brand new
vehicle will be safer on day one.

With the shuttle, loss of the mission also almost always means loss of the
crew. At least Ares has a launch escape system worthy of the name.