On Mar 22, 2:44*am, Yousuf Khan wrote:
Bluuuue Rajah wrote:
BradGuth wrote in
:
Why reinvent the wheel?

To save both time and money. *IIRC, the Ares I is just a shuttle SRM
stacked on top of an Atlas, both of which are off the shelf components. *
To reconstruct the Saturn V would actually require effort, but they had
the Ares I designed about two months after Bush announced the new plan.

So it looks like solid rockets are now fully trusted at NASA. During the
Moon missions, NASA management (i.e. Wernher von Braun) distrusted solid
rockets for good reason, and so solid rockets were off-limits. That's
why Saturn V was so big, it was liquid rocket that needed to leave Earth
orbit. You need a lot of liquid to do that.

As it turned out solid rockets were the reason for the first of the two
Space Shuttle disasters, Challenger. So NASA's initial objections to
solid rockets was verified. I suppose those redesigned O-rings have now
made these solid rockets "rock solid" for NASA.

* *Yousuf Khan

Redesign wasn't much. Some of the rocket engineers thought it was
still an accident waiting to happen, but the contractor made a ton of
bucks, everybody got promoted and people were happy. Oh yeah, the
whistleblower got fired.
Biggest solution was changing launch parameters and not letting it
launch in freezing weather. There was O ring charring on earlier
flights, we'd see reports, but not being rocket types, figured that's
what happens in solids. Got something burning in a tube, stuff chars.
Of course if you get burnthrough, nasty things happen.

Big reason for liquid fuel, you can throttle it up and down. Can't do
that on solids. They tried that on SRAM II, motor blew up. Cheney
eventually canned it. There were tons of other issues. I had the
feeling Boeing wasn't really thrilled about testing it, had a bitch of
a time getting parameters for it. Instrumentation guys were
reassigned, stuff I got was almost a year out of date. And remember,
engineers tinker with parameters almost up to time of flight. Don't
have a up to date list of what is where and how its to be changed to
digital from analog, you've pretty much got crap for data.