Programming "error"

Here's a theory on contributing causes of the destruction of Columbia which
I hadn't heard before. This article was published about a week after the
loss:



http://www.pscu.com/articles/daily/8,6,1,0210,03.html



"The program assumed that the drag on the left wing was not the result of
damage but rather of atmospheric drag that would require a course correction
in order to maintain proper course."

The article postulates that the maneuver resulted from a lack of
sophistication in the flight software, and that the maneuver aggravated the
structural and thermal damage to the wing---the author refers to the "error"
as "fatal". Setting aside arguments about whether "lack of intelligence"
in the code == "bug" for another time, I don't recall that this idea came
up in the accident review. Was it dealt with somewhere else?

JJ Robinson II
Houston.TX

jjrobinson2 wrote:

The article postulates that the maneuver resulted from a lack of
sophistication in the flight software, and that the maneuver aggravated the
structural and thermal damage to the wing---the author refers to the "error"
as "fatal".

If one uses the words "fatal" and "error" in conjunction with the idea
that a course correction caused (or contributed) to the accident, I
suggest that one consider what would have happened if there were no
course correction. The drag would have increased with time, which would
bring increased vehicle yaw to the left as time went on. The goal of
the flight software at that point the nose in a specific direction
(probably yaw of zero), so some outside force acting to yaw the vehicle
is going to be countered by the flight software firing some RCS jets to
correct this.


Setting aside arguments about whether "lack of intelligence"
in the code == "bug" for another time, I don't recall that this idea came
up in the accident review. Was it dealt with somewhere else?

Yes, the flight software was checked out, along with all software tools
which are used to create any numbers that get fed into the onboard
computers prior to flight. However, all programs are limited in their
"intelligence". How would the Shuttle flight software know how to
handle different degrees and types of damage to the orbiter? That would
be an extremely complex problem to solve. Complexity allows more room
for error, and drives up the cost of certification.

jjrobinson2 wrote:
Here's a theory on contributing causes of the destruction of Columbia
which
I hadn't heard before. This article was published about a week after
the
loss:

http://www.pscu.com/articles/daily/8,6,1,0210,03.html


I don't know much about the shuttle but that article reads like a bunch
of sensationalist bull****.

stou

I seem to recall this when alternate trajectories to mitigate dame was
discussed. However, you had to know of damage first, how would you expect
the flight software to know the difference between different drag causing
effects?

Brian

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"jjrobinson2" wrote in message
...
Here's a theory on contributing causes of the destruction of Columbia
which
I hadn't heard before. This article was published about a week after the
loss:



http://www.pscu.com/articles/daily/8,6,1,0210,03.html



"The program assumed that the drag on the left wing was not the result of
damage but rather of atmospheric drag that would require a course
correction
in order to maintain proper course."

The article postulates that the maneuver resulted from a lack of
sophistication in the flight software, and that the maneuver aggravated
the
structural and thermal damage to the wing---the author refers to the
"error"
as "fatal". Setting aside arguments about whether "lack of intelligence"
in the code == "bug" for another time, I don't recall that this idea
came
up in the accident review. Was it dealt with somewhere else?

JJ Robinson II
Houston.TX






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"Brian Gaff" wrote in message
. uk...
I seem to recall this when alternate trajectories to mitigate dame was
discussed. However, you had to know of damage first, how would you expect
the flight software to know the difference between different drag causing
effects?

Brian

--

Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:


I can imagine some ways the information about various sources and types of
unusual aerodynamic forces could be integrated and processed, all with the
benefit of hindsight.

I was more interested at this point in whether any conclusive evidence
remains that an automatic correction by the flight controls actually
aggravated the damage somehow. If one had full information about the degree
and type of damage to the craft, what would the proper control response have
been--- enter with a small port yaw to protect the damaged area?

JJ Robinson II

In article ,
"jjrobinson2" wrote:

I was more interested at this point in whether any conclusive evidence
remains that an automatic correction by the flight controls actually
aggravated the damage somehow. If one had full information about the degree
and type of damage to the craft, what would the proper control response have
been--- enter with a small port yaw to protect the damaged area?

This idea was debated here endlessly, circa February - July 2003.
Google for the gory details if you're morbidly curious. The short and
sweet answer is that modified entry profiles wouldn't have been
sufficient to make a difference.

--
Herb Schaltegger, B.S., J.D.
"Never underestimate the power of human stupidity."
~ Robert A. Heinlein
http://www.angryherb.net

jjrobinson2 wrote:
Here's a theory on contributing causes of the destruction of Columbia which
I hadn't heard before. This article was published about a week after the
loss:


http://www.pscu.com/articles/daily/8,6,1,0210,03.html

In the immortal words of Jim Morrisson: "I think it's a bunch of
bull****, myself."

--
bp
Proud Member of the Human O-Ring Society Since 2003