> > I am reluctant to trust the article in such detail, I have seen 
> > similar articles to get such details subtly wrong.
> 
> Ok, you have a point with this. But then, we don't know 
> anything... I was just assuming the article was correct, and 
> arguing from that position. If you know it wasn't, let's talk 
> about this. If you only suspect it might not be, then there's 
> not really much to say anyway...

IIRC the article stated that they 'specified the wrong address'. From
this you extrapolated that they used an address-value interface, and
that they should have used a name-based interface. For me that's two
steps that are not 100% justified from such an article.

> I argued that it seemed -- from the article -- that there 
> were not enough safeguards (in ground software and 
> procedures) against an almost predictable error.

OK, so at least we agree on 'no (proven) flight software error' :)

> Right. But the loss of the craft (total cost $210M) shows 
> that there was a problem. /This/ was terribly expensive. 
> Apparently a few $10k in better procedures/ground software 
> would have been well spent.

But that is not fair: if you create such a directive that amount of
money must be spent on *every* spacefraft, not just this one.

And IIRC the spacecraft was lost well after its intended lifetime, so in
some bookkeeping sense the loss was $ 0. That is probably not right
either, but certainly not the total cost of the craft!

> No clue. I'd guess over $1, after you factor everything in. 

IIRC it was more like $100. But maybe someone who is currently into such
systems can give a ballpark figure.

> But the more expensive, the more it is an argument in favor 
> of what I'm trying to say: put better safeguards in ground 
> procedures and software, so that the probability of such 
> silly things is smaller still.

But that cost exposion factor (a resistor in your TV set probably costs
~ $0.0005 .. $0.05, depending on which costs you include) also applies
to software, so when you guesstimate $10k the cost for space-related
software (even gound software) will be an order of magnitude higher. You
must take that into account when you compare it to the loss.

> If a single operator mistake 
> can wreak such havoc, it's generally not the operator's 
> fault, it's the whole procedure that's missing something. 

That's a good first-order assumption. 

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
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docent Hogeschool van Utrecht: www.voti.nl/hvu
 
 

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