Re: Ariane5 FAQ

[Vinzent Hoefler <ada.rocks@jlfencey.com>]

Hyman Rosen wrote:

>Vinzent Hoefler wrote:
>> Well, so I ask again, *which* reasons were that? I see none, besides
>> the good belief, it won't go wrong.
>
>They took a piece of self-contained hardware and moved it
>from one rocket to another. They thought the software would
>work.

Well, one way or another - it did. It did exactly what is was supposed
to do.

>We have to assume that the Ariane 5 folks were not
>complete blithering idiots,

Dangerous assumption. ;)

>so they must have has readsons
>to assume it would work.

So what you're trying to say is that they must have reasons just
because they did it? Sorry, but I wouldn't consider this a strong
argument.

Alas, people do a lot of things for no apparent reason. This is
sometimes ok if we are talking about "normal" life, but if there is a
technical background, doing so can become very dangerous.
In that area we should usually try to prove our beliefs (and
obviously, this wasn't done in the Ariane 5 case). This proving
process usually involves some reasons for this or that. So what
reasons had they and could they prove the correctness? Obviously the
answer is "No, they couldn't, because they didn't.".
A reason like "it worked on the Ariane 4" is not really a reason, as I
have already tried to point out. Personally for me it looks like they
just *assumed* the IRS would work. This might have been the reason for
the decision to just reuse it, right. But if you look deeper, they
didn't seem have a reason for assuming that, they simply just believed
it.

What I mean is, you can probably not prove that somebody really loves
his wife (BTW, does he have a reason for doing so?[0]) but you can
tell that the candle on the table will shed some fancy light on her,
because there is a reason for that it is doing so (something with high
temperature, gases, electrons, molecular movements and photons and
such stuff, I guess ;). Well, bad example, try to go into detail and
predict the exact movement of the flame...


Vinzent.

[0] Because he just does? :-)