Re: Dyna-Soar question

In article <IE4Hy9.2rv@xxxxxxxxxxxxx>, henry@xxxxxxxxxxxxx says...
>
> <snip>
>
>
> You're assuming that any failure is a random hardware failure, rather than
> a design flaw. The latter can take out a redundant guidance system
> completely, as witness the first Ariane 5 launch.

There is another class of failure beyond hardware and design failures --
faliure to completely understand and model the flight regime. I admit,
this applied to Dyna-Soar's entry more than its boost phase -- back in
the 60s we understood exit aerodynamics a lot better than we understood
how unpowered winged vehicles performed in hypersonic flight regimes.

I'll remind y'all that John Young took manual control over STS-1 when he
and Crippen watched the stagnation point shift off the nose and climb
towards the windows (*) under the obviously-less-than-perfect automatic
entry program. So while an automated navigation and flight control
system would obviously have been useful (and possibly necessary for
precision flying) on Dyna-Soar, they would almost have to have some
manual back-up capability, during both launch and entry. Because if the
hypersonic gliding regime was understood imperfectly enough in 1981 that
Young was forced to go to manual control during the shuttle's first
entry, I can't imagine that *any* automated guidance system could have
achieved a successful Dyna-Soar entry in 1965.


* - IIRC, while I never heard about this back in '81, I've seen some
remarkable stories about the event in the last few years. IIRC, one was
in a post here by our beloved Mary Shafer... but I could be wrong with
that attribution.

--

"The problem isn't that there are so | Doug Van Dorn
many fools; it's that lightning isn't | dvandorn1@xxxxxxxxxxxxxxxx
distributed right." -Mark Twain
.

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