From: Paul Lutus <nospam@...>
Date: 2006-11-25T04:48:41+09:00
Subject: Re: Bug in ruby?

Jim Cochrane wrote:

/ ...

>> The bug that cause Mars Polar Explorer to prematurely shut down its
>> engine and fall the last 100 meters to the surface of Mars, never to be
>> heard from again.
> 
> Due to a missing or incorrect unit conversion, right?!

No, I left that one off my list because it was simple human error, not
really software-related. One outfit was using English units, the other one
Metric, and they failed to realize the discrepancy until the spacecraft was
of course.

The error I am speaking of caused a Mars spacecraft to shut down its descent
engine prematurely due to the misreading of a sensor. At least that's the
best theory so far for a spacecraft that didn't have any terminal phase
telemetry.

> Or how about the Ariane 5 (
> http://www.around.com/ariane.html
> ).

Yep. Another bad one.

> I don't remember ever hearing a description of the defect (or 
> defects) that caused the DIA baggage sysgtem to fail (
> http://www.cis.gsu.edu/~mmoore/CIS3300/handouts/SciAmSept1994.html
> ).

I think that one was mostly bad mechanical design. They were trying to do
away with human baggage handlers entirely.

-- 
Paul Lutus
http://www.arachnoid.com