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scott wrote:
> But the million dollar question is, was the shuttle taking off in
> ambient conditions outside of the designed temperature range, or had the
> designers failed to check that every component would remain within its
> operating range during take off?
IIRC, it was bloody cold that day, and several engineers advised against
the launch due to the temperatures. But the actual spec sheet? IDK.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> That seems most common - for implementations that involve life and death,
>> the systems tend to be custom-built for a specific purpose, not based on
>> a general purpose operating system.
>
> It's not just the software, all the hardware will also need to be
> certified for applications where human life is at risk. You think your
> PC is reliable? You trust it enough, that if it ever failed you'd die?
> Didn't think so :-)
The work I do affects human life in the most indirect way imaginable.
(Specifically: It is hypothetically plausible that some obscure computer
system to malfunction in such a way as to generate erroneous data that
somehow manages both to "look" geniune, and also appear to show that a
drug is safe when in fact it is not.)
Even though what my company does is extremely indirectly linked with
human health, the level of checking and certification involved is quite
phenominal. And we don't even MAKE anything that goes anywhere near a
human being! We just produce numbers.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> But the million dollar question is, was the shuttle taking off in ambient
>> conditions outside of the designed temperature range, or had the
>> designers failed to check that every component would remain within its
>> operating range during take off?
>
> IIRC, it was bloody cold that day, and several engineers advised against
> the launch due to the temperatures. But the actual spec sheet? IDK.
Well I'd jolly well hope that every single part of the shuttle would be
designed to work in the temperature range specified on the spec sheet!
Doesn't sound very NASA-like to have some Engineer going "oh it's a bit
chilly today old chaps, that o-ring might not be so good". Where's the
temperature spec of the O-ring? Where's the simulation/test results of
expected temperatures at each point on the shuttle? Why wasn't this brought
up during the design stage?
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On Tue, 15 Jul 2008 17:29:19 +0100, Doctor John <joh### [at] home com> wrote:
>Stephen wrote:
>> On Tue, 15 Jul 2008 07:36:10 -0500, Mike Raiford <mra### [at] hotmailcom> wrote:
>>
>>> (PID - Andrew should know what this means, Proportional,
>>> Integral, Derivative )
>>
>> Thank you I read it as "Piping & Instrumentation Diagram"
>
>...and I read it as Prolapsed Intervertebral Disc
>
>JohLOL
--
Regards
Stephen
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On Tue, 15 Jul 2008 17:41:00 +0100, Orchid XP v8 <voi### [at] devnull> wrote:
>>> (PID - Andrew should know what this means, Proportional,
>>> Integral, Derivative )
>
>Andrew did *not* know what it means. I was assuming Process ID...
Since when did you start speaking about yourself in the 3rd person?
:)
--
Regards
Stephen
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Stephen <mcavoysAT@aolDOTcom> wrote:
> On Tue, 15 Jul 2008 17:41:00 +0100, Orchid XP v8 <voi### [at] devnull> wrote:
>
> >>> (PID - Andrew should know what this means, Proportional,
> >>> Integral, Derivative )
> >
> >Andrew did *not* know what it means. I was assuming Process ID...
>
> Since when did you start speaking about yourself in the 3rd person?
> :)
> --
>
> Regards
> Stephen
Since he is at version 8? ;-)
Regards,
bluetree
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>> IIRC, it was bloody cold that day, and several engineers advised
>> against the launch due to the temperatures. But the actual spec sheet?
>> IDK.
>
> Well I'd jolly well hope that every single part of the shuttle would be
> designed to work in the temperature range specified on the spec sheet!
>
> Doesn't sound very NASA-like to have some Engineer going "oh it's a bit
> chilly today old chaps, that o-ring might not be so good". Where's the
> temperature spec of the O-ring? Where's the simulation/test results of
> expected temperatures at each point on the shuttle? Why wasn't this
> brought up during the design stage?
The information I heard was that it was an unusually cold day, and the
entire craft was covered in sheets of solid ice, and several people
suggested that they hadn't really tested for this and it would be better
to wait for the weather to change. But that didn't suit the launch
schedule, so they launched anyway.
Weather the temperatures were actually outside the spec sheet I have no
idea. (I'm also not actually sure how accurate the above tale is, for
that matter.) I'm sure temperature ranges were tested, but ice? Maybe
they hadn't thought about that. IDK.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> The information I heard was that it was an unusually cold day, and the
> entire craft was covered in sheets of solid ice, and several people
> suggested that they hadn't really tested for this and it would be better
> to wait for the weather to change. But that didn't suit the launch
> schedule, so they launched anyway.
>
> Weather the temperatures were actually outside the spec sheet I have no
> idea. (I'm also not actually sure how accurate the above tale is, for that
> matter.) I'm sure temperature ranges were tested, but ice? Maybe they
> hadn't thought about that. IDK.
OK, I just read about it on Wikipedia, and apparently they knew of the
design flaw that the o-rings could be compromised at low temperatures, but
they didn't address the problem. I wonder who the most senior person was
who knew about this, and why they didn't escalate it further...
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Jim Henderson wrote:
> On Wed, 16 Jul 2008 09:17:21 -0700, Darren New wrote:
>
>> And I wouldn't be surprised, anyway, if some MS software had a bug that
>> caused some patient to get over-dosed with radiation during cancer
>> treatment or some such.
>
> I would be, since the machines that control that sort of thing tend to be
> custom-built and not PC-controlled, at least not that I've seen
> (admittedly, I've not spent a lot of time in cancer treatment facilities).
>
> Jim
Even the custom built control software isn't always bug free.
http://en.wikipedia.org/wiki/Therac-25
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> Even the custom built control software isn't always bug free.
> http://en.wikipedia.org/wiki/Therac-25
That's just bad hardware design, there should have been some sort of
mechanical interlock to prevent that happening.
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