[AR] Re: Valley Tech throttleable restartable solids (!)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Thu, 26 Mar 2020 20:24:09 -0400 (EDT)
On Thu, 26 Mar 2020, roxanna Mason wrote:
it turned out that shutdown
transient loads would be too high for the orbiter and ET structures.
Did not know this was ever a consideration. So instead of
shelving SRB's for liquid boosters they rolled the dice. Another
example of politics over engineering.
The Shuttle program, alas, had a bad case of one of the problems Nevil
Shute describes in the R-101 project: once a decision was made and money
started being spent based on it, admitting that the decision had been a
mistake and money had been wasted was deemed too embarrassing.
Earlier example: When NASA finally accepted non-reusable drop tank(s),
that should have made it possible to build something like the Lockheed
StarClipper concept -- with all the engines in the orbiter and no separate
booster -- which had previously been ruled unacceptable because it used a
drop tank. People did notice this, but the decision to build a two-stage
Shuttle with separate booster(s) could not be changed.
Later example: When the orbiter design came in considerably overweight,
reducing payload fraction and threatening a considerable loss in payload,
the right answer was to back up and design a somewhat larger Shuttle that
would have the desired payload despite the smaller payload fraction.
Instead an expensive and painful mass-reduction scrub was done, and one
consequence of that was that a lot of "operability" aids like built-in
work platforms were deleted, regardless of what it would do to ops cost.
And for a non-Shuttle example, the whole sad story of Ares I was one
instance after another of designers doggedly carrying on with a
fundamentally flawed basic design, because it could not be changed no
matter how difficult the implementation proved to be.
Henry
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