Old engineering maxim "If it ain't broke, don't fix it"... But itwas broke!

In article ,
The Ghost In The Machine wrote:
In sci.physics,

wrote
on Mon, 01 Aug 05 09:12:31 GMT
:
snip

Debug the damned thing. I don't remember hearing about
foam problems in the 80s. If these problems didn't exist
back then, what changed to cause this foam to fall to
pieces when shaked and baked.

Who says they didn't?

There were no reports.

.. Until 1986 the world probably didn't know
O-rings existed,

Yes the world knew. O-rings had already been in the news.

.. and they certainly hadn't considered that they
could burn through.

Crack, IIRC.


I suspect similar issues here.

Nope. The problems are worse, I suspect. I'll bet engineers
can't wipe their ass without five requisitions in triplicate
plus 10 layers of approval; note that this involves two branches
of managements.

/BAH

Subtract a hundred and four for e-mail.

In article ,
Uncle Al wrote:
wrote:
snip

The original working foam was Freon-blown. The original SSB joint
calk was asbestos- and chromate-based. Replacement of both with
Enviro-whiner "equivalents" proved to need more studies in each case.
You can't condemn a whole program because of a component failure.

I heard on the news this morning that your local envirotypes
have now envoked an EPA edict on cows. I'd like to see those
suits install a scrubbing muffler on a bull.

/BAH

Subtract a hundred and four for e-mail.

jerry warner wrote:
What a great opportunity for the Chinese. We pay for their oil, subsidise
their economy, and now give them space! I wonder if they will build a
monument
to NASA or just snicker to their sides.

You are blaming China for your own nations failures. In a way this is
good because by believing things wrong, it can only help to keep you
making more mistakes.





Sam Wormley wrote:

Posted on Sun, Jul. 31, 2005
Ref: http://www.contracostatimes.com/mld/...n/12269385.htm

Old maxim didn't apply to NASA's foam problem
By John Schwartz
NEW YORK TIMES

"We are ready to fly."

It was June 24, and William Parsons, NASA's shuttle
program manager, was speaking to reporters on a
conference call from the Kennedy Space Center at
Cape Canaveral, Fla.

Two-and-a-half years of study and struggle, he told
them, were over at long last.

The shuttle Discovery could blast off in July.

At a meeting that day, shuttle managers had ruled
that the chances that debris from the external fuel
tank would strike the Discovery at liftoff -- in
the kind of accident that doomed the Columbia and
its crew in 2003 -- had been reduced to "acceptable
levels."

The possibility that a large chunk of insulating
foam might break away from a section of the tank
called the protuberance air load ramp, or PAL,
never came up.

It had been ruled out months earlier, checked off
on a long list of items no longer worthy of concern
or of urgent action.

Last Tuesday, NASA's view that it had produced the
safest fuel tank in shuttle history was shattered
two minutes into the flight of the Discovery. Two
spacewalking astronauts tested repair techniques
Saturday.

The 0.9-pound piece of foam that fell from the PAL
ramp on liftoff, which could have led to another
catastrophe if it had ripped away a minute sooner,
forced the immediate suspension of future shuttle
flights until the problem could be resolved.

How did it happen? An examination of the efforts to
resolve the PAL ramp issues reveals a succession of
missed opportunities and dubious judgments, not
just in the two-and-a-half years since the Columbia
disaster but over the life of the program.

Potentially useful tests were not performed.
Innovative solutions were not seriously pursued.
Tantalizing clues were missed.

In the end, the old engineering maxim "If it ain't
broke, don't fix it" trumped misgivings about a
part that had not shed any foam, as far as anyone
knew, since 1983.

"After two-and-a-half years, they should have been
able to fix the foam," said Paul Czysz, a professor
emeritus of aeronautical engineering at St. Louis
University and a veteran consultant to NASA.

Now, with the future of the International Space
Station in the balance and the shuttle fleet just
five years away from a mandatory retirement imposed
by President Bush, NASA is still trying.

In the dawn of the shuttle program, NASA rules said
no foam at all should be allowed to hit the shuttle
and possibly damage the fragile heat-resistant
tiles that cover its aluminum skin.

But fidelity to those standards was relaxed over
time; in fact, foam fell off of the PAL ramp in two
early missions, including the one in June 1983 on
which Sally Ride became the first U.S. woman in
space.

There may have been many more incidents, but dozens
of shuttle missions have been launched at night
with no visual record of foam, and the tanks
themselves are at the bottom of the ocean.

As the early tank was replaced with two lighter
successors, the PAL ramps remained -- one a 19-foot
baffle along a channel for cables and pressurized
lines along the forward end of the tank and the
other a 37-foot strip along the flank of the
cylindrical midsection of the fuel tank.

And as experience showed NASA that shuttles
returned safely despite more than 100 nicks and
gouges requiring repair on many flights, the
concerns abated over time.

Until Feb. 1, 2003, the day the Columbia
disintegrated on its way home to Cape Canaveral.

After the accident, NASA examined all possible
sources of liftoff debris, eventually identifying
more than 170.

The PAL ramp became a focus of attention: Like the
bipod arm ramp, the part of the tank implicated in
the Columbia disaster, it is covered with foam by
hand.

NASA conducted extensive wind-tunnel tests to
determine whether the ramp could be removed.

The tests of the ramp areas were all focused on
aerodynamics -- helping determine how air would
flow around the craft and tank, or to improve
understanding of where foam or ice or other debris
might fly should it fall free of the tank.

But there were no tests of the PAL foam itself at
speeds, pressures or vibrations experienced during
ascent.

So the only tests of how the material might hold up
under the rigor of launching were the launchings
themselves, with crew aboard.

For many aeronautical engineers, a central rule in
developing an aircraft is taking its components
beyond the breaking point.

Michael Griffin, NASA's new administrator and an
engineer, said Friday, engineers believe, "If it
ain't broke, don't fix it."

"We debated and discussed whether the PAL ramp was
broken" in the months that followed the Columbia
disaster, Griffin continued.

"The conclusion we came to was the wrong one, but
the conclusion we came to after considerable study
was that it was better to fly as is."

NASA engineers had already seen how fixes can break
things.

After they made a minor change in the foam
application process in the late 1990s to comply
with environmental rules, small divots of foam
rained off of the tank during ascent.

The phenomenon, called popcorning, was caused by
trapped bubbles; NASA solved the problem by venting
the foam with tiny holes, but it was a reminder, if
any was needed, that seemingly small changes can
have profound effects.

Ultimately, the accident board recommended that
NASA find ways to prevent any shedding of foam or
other debris. And NASA gained confidence during the
time between flights that it was making progress.

Among other things, it improved the training
processes for applying foam by hand.

At the Michoud tank assembly plant in Louisiana, an
observer monitors every worker spraying foam --
"for every sprayer there's a watcher, a second pair
of eyes," said June Malone, a NASA spokeswoman.

But the tank that flew with the Discovery last week
was made before the new procedures went into
effect, and NASA stopped short of requiring that
the ramps be redone, said a spokesman, Martin
Jensen.

After the Columbia accident board issued its
scathing report on the causes of the disintegration
-- especially a "broken safety culture" at NASA
that had grown complacent about all sorts of risks
-- another independent group was set up to monitor
NASA's progress in fulfilling the accident board's
recommendations.

That group, called the Stafford-Covey task force
after the two former astronauts who led it,
accepted NASA's argument that the PAL ramp did not
urgently require alteration.

At its final meeting in June, however, it also
found that NASA had failed to meet the goal of
eliminating all debris.

The group took issue with the way NASA determined
that the foam chunks that might still fall off the
tank were too small to cause critical damage.

And it criticized NASA's tendency to depend on
computer simulations when physical experiments
might yield more valuable data.

Ultimately, however, the group accepted NASA's
contention that it had raised the level of safety
in general.

A NASA engineer who works on tank safety issues
said other areas of foam shedding from the
Discovery's tank were even more troubling than the
PAL ramp loss -- especially a divot that popped
from the vicinity of the left-hand bipod strut, the
spot that shed the foam that brought down Columbia.

The loss of foam from that spot after so much work
to correct the problem, he went on, proves that the
problem is still far more complex than NASA
understands.

So the space agency is back to the drawing board.

Copyright (c) 2005 New York Times

On Mon, 01 Aug 2005 04:00:04 GMT, The Ghost In The Machine
wrote:

In sci.physics, jabara

wrote
on Sun, 31 Jul 2005 21:50:43 -0500
ews.net:

"Sam Wormley" wrote in message
...
Posted on Sun, Jul. 31, 2005
Ref: http://www.contracostatimes.com/mld/...n/12269385.htm

Old maxim didn't apply to NASA's foam problem
By John Schwartz
NEW YORK TIMES

"We are ready to fly."



Think about it.
You have to spray a tank with foam that insulates and hardens at sea level.
It is then exposed to severe vibration and less pressure, so the foam both
expands and cracks.

Bad design?
Bad Foam, or could any Foam ever do the job?

I suspect no foam will ever work. Foam, after all, is
substance + air.

two components that react (a poly ol and an isocyante) and increase in
volume.
once the reaction is complete, its a hardened mass.


Air is under pressure (this is proven
in a number of ways). The pressure goes down outside,
the foam expands inside.

not once its cured. once cured, it might as well be a hunk of wood.

what you do say, and may have some credence, is that whatever air is
inside the foam has to work its way out. i'd like to see how
permeable the foam is.


If the bubble skin is thin enough, it might work --
however, if not, well...


simplest solution: Foam the inside.

(There is the remote possibility of placing the entire
tank in a near-vacuum, or perhaps using steam to apply the
foam, allowing the water vapor to fill the bubbles, which
collapse when the steam cools sufficiently. The former
looks highly impractical; the latter has the problem that
the steam condenses to water, which may, given the wrong
conditions, form a skin between foam and tank, ready
to detach...)

I'm beginning to wonder if they'll have to eschew the
foam and fabricate a gigantic heating coil underneath the
shuttle (between the bimounts). The main problem with
that is that the heating element might break away too,
in flight -- but it might beat being hit with chunks of ice,
especially if the element is sprayed with some sort of
epoxy or superglue.


[Old Saying in rocket/aerospace industry, "FIFI" =F*ck It, Fly It.]


Then die in it, apparently. It's admittedly an interesting
tradeoff: how much is an astronaut's life worth?

(Considering that we get about 20 deaths in Iraq *per day*
because of operations there, 17 deaths in the span of
over 30 years isn't all that bad. But it's still 17 deaths.)

Uncle Al wrote:
Uncle Al has the solution!!!

Yes, to quit being stuck in the 1960's (on either side of the debate),
get with the times: SpaceShipOne -- which made a mockery of the whole
process, going up at 1/1000 the cost without all the on-ground mission
control nonsense, on-ground bureaucracy, or on-board
bureaucracy-as-excessive-computerization. It's time for NASA, ESA,
etc-SA to step aside and make way for the private sector. The SA's are
obsolete; the mode of thought that everyone seems to be still stuck in
antuomatically treating "space" and "it's gotta be done by the gummit"
as synymous is, itself, obsolete, as are its prologues (and critics).
Despite the bulging mass of geezerifying baby-boomers now suffocating
the levers of power, and passing through society like a bad movement
that it will never been soon enough to see through and out, this is not
the 1960's. Both the times and debates on both sides are past. Their
vision of space (or the lack thereof) has been subsumed by more nimble
agents.

In sci.physics,

wrote
on 2 Aug 2005 14:01:44 -0700
.com:
Uncle Al wrote:
Uncle Al has the solution!!!

Yes, to quit being stuck in the 1960's (on either side of the debate),
get with the times: SpaceShipOne -- which made a mockery of the whole
process, going up at 1/1000 the cost without all the on-ground mission
control nonsense, on-ground bureaucracy, or on-board
bureaucracy-as-excessive-computerization. It's time for NASA, ESA,
etc-SA to step aside and make way for the private sector. The SA's are
obsolete; the mode of thought that everyone seems to be still stuck in
antuomatically treating "space" and "it's gotta be done by the gummit"
as synymous is, itself, obsolete, as are its prologues (and critics).
Despite the bulging mass of geezerifying baby-boomers now suffocating
the levers of power, and passing through society like a bad movement
that it will never been soon enough to see through and out, this is not
the 1960's. Both the times and debates on both sides are past. Their
vision of space (or the lack thereof) has been subsumed by more nimble
agents.


Bear in mind how far up SS1 went, and it had lots of help:
the "white Knight". However, it does show promise for
the private sector, and we Americans have always been a
bit space-happy.

You might also remember the risk the pilot took; the craft
was nearly uncontrollable during one flight. (Shades of
Chuck Yeager? :-) )

--
#191,
It's still legal to go .sigless.

Using the extensive knowledge and experience gained by Nasa and
earlier pioneers. I wholeheartedly applaud the private sector doing an
outstanding job, and firmly believe that the future of space travel
must include them.

I don't want, however, to minimize the accomplishments and
contributions that NASA has made, and will make. Some projects are
just not a cost effective business model for the private sector to
take on. For example, make a viable business case that you can sell to
your stockholders for launching the Pioneeer spacecraft, or the Apollo
program.

Space is 'reeeaaallly BIG'! There's enough room for NASA and the
private sector.

- Chris

writes:

Uncle Al wrote:
Uncle Al has the solution!!!

Yes, to quit being stuck in the 1960's (on either side of the debate),
get with the times: SpaceShipOne -- which made a mockery of the whole
process, going up at 1/1000 the cost without all the on-ground mission
control nonsense, on-ground bureaucracy, or on-board
bureaucracy-as-excessive-computerization. It's time for NASA, ESA,
etc-SA to step aside and make way for the private sector. The SA's are
obsolete; the mode of thought that everyone seems to be still stuck in
antuomatically treating "space" and "it's gotta be done by the gummit"
as synymous is, itself, obsolete, as are its prologues (and critics).
Despite the bulging mass of geezerifying baby-boomers now suffocating
the levers of power, and passing through society like a bad movement
that it will never been soon enough to see through and out, this is not
the 1960's. Both the times and debates on both sides are past. Their
vision of space (or the lack thereof) has been subsumed by more nimble
agents.


--
(. .)
=ooO=(_)=Ooo========================
Chris McMahan | cmcmahan-at-one.net
====================================

A new material for coating the shuttle:

http://www.azcentral.com/offbeat/art...list23-ON.html

*****QUOTE*****
NEW YORK - Spin magazine has built a veritable rock star Frankenstein,
composed of Michael Stipe's skull, Elvis Presley's pelvis and Madonna's
bellybutton.

Spin charts the 25 "most incredible" rock star body parts in its September
issue, now on newsstands. Madonna's navel tops the list.

"It's what first marked her as a mainstream provocateur," senior Spin writer
Marc Spitz writes. At No. 2 is the liver of Rolling Stones' Keith Richards,
which is so durable, Spitz writes, that "when Richards finally passes,
they'll line the exterior of the space shuttle with his liver tissue."
*****END QUOTE*****

There's the answer!

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/

To reply, remove Delete and change period com to period net
************************************************** ************


"Sam Wormley" wrote in message
...
Posted on Sun, Jul. 31, 2005
Ref: http://www.contracostatimes.com/mld/...n/12269385.htm

Old maxim didn't apply to NASA's foam problem
By John Schwartz
NEW YORK TIMES

"We are ready to fly."

It was June 24, and William Parsons, NASA's shuttle
program manager, was speaking to reporters on a
conference call from the Kennedy Space Center at
Cape Canaveral, Fla.

Two-and-a-half years of study and struggle, he told
them, were over at long last.

The shuttle Discovery could blast off in July.

At a meeting that day, shuttle managers had ruled
that the chances that debris from the external fuel
tank would strike the Discovery at liftoff -- in
the kind of accident that doomed the Columbia and
its crew in 2003 -- had been reduced to "acceptable
levels."

The possibility that a large chunk of insulating
foam might break away from a section of the tank
called the protuberance air load ramp, or PAL,
never came up.

It had been ruled out months earlier, checked off
on a long list of items no longer worthy of concern
or of urgent action.

Last Tuesday, NASA's view that it had produced the
safest fuel tank in shuttle history was shattered
two minutes into the flight of the Discovery. Two
spacewalking astronauts tested repair techniques
Saturday.

The 0.9-pound piece of foam that fell from the PAL
ramp on liftoff, which could have led to another
catastrophe if it had ripped away a minute sooner,
forced the immediate suspension of future shuttle
flights until the problem could be resolved.

How did it happen? An examination of the efforts to
resolve the PAL ramp issues reveals a succession of
missed opportunities and dubious judgments, not
just in the two-and-a-half years since the Columbia
disaster but over the life of the program.

Potentially useful tests were not performed.
Innovative solutions were not seriously pursued.
Tantalizing clues were missed.

In the end, the old engineering maxim "If it ain't
broke, don't fix it" trumped misgivings about a
part that had not shed any foam, as far as anyone
knew, since 1983.

"After two-and-a-half years, they should have been
able to fix the foam," said Paul Czysz, a professor
emeritus of aeronautical engineering at St. Louis
University and a veteran consultant to NASA.

Now, with the future of the International Space
Station in the balance and the shuttle fleet just
five years away from a mandatory retirement imposed
by President Bush, NASA is still trying.

In the dawn of the shuttle program, NASA rules said
no foam at all should be allowed to hit the shuttle
and possibly damage the fragile heat-resistant
tiles that cover its aluminum skin.

But fidelity to those standards was relaxed over
time; in fact, foam fell off of the PAL ramp in two
early missions, including the one in June 1983 on
which Sally Ride became the first U.S. woman in
space.

There may have been many more incidents, but dozens
of shuttle missions have been launched at night
with no visual record of foam, and the tanks
themselves are at the bottom of the ocean.

As the early tank was replaced with two lighter
successors, the PAL ramps remained -- one a 19-foot
baffle along a channel for cables and pressurized
lines along the forward end of the tank and the
other a 37-foot strip along the flank of the
cylindrical midsection of the fuel tank.

And as experience showed NASA that shuttles
returned safely despite more than 100 nicks and
gouges requiring repair on many flights, the
concerns abated over time.

Until Feb. 1, 2003, the day the Columbia
disintegrated on its way home to Cape Canaveral.

After the accident, NASA examined all possible
sources of liftoff debris, eventually identifying
more than 170.

The PAL ramp became a focus of attention: Like the
bipod arm ramp, the part of the tank implicated in
the Columbia disaster, it is covered with foam by
hand.

NASA conducted extensive wind-tunnel tests to
determine whether the ramp could be removed.

The tests of the ramp areas were all focused on
aerodynamics -- helping determine how air would
flow around the craft and tank, or to improve
understanding of where foam or ice or other debris
might fly should it fall free of the tank.

But there were no tests of the PAL foam itself at
speeds, pressures or vibrations experienced during
ascent.

So the only tests of how the material might hold up
under the rigor of launching were the launchings
themselves, with crew aboard.

For many aeronautical engineers, a central rule in
developing an aircraft is taking its components
beyond the breaking point.

Michael Griffin, NASA's new administrator and an
engineer, said Friday, engineers believe, "If it
ain't broke, don't fix it."

"We debated and discussed whether the PAL ramp was
broken" in the months that followed the Columbia
disaster, Griffin continued.

"The conclusion we came to was the wrong one, but
the conclusion we came to after considerable study
was that it was better to fly as is."

NASA engineers had already seen how fixes can break
things.

After they made a minor change in the foam
application process in the late 1990s to comply
with environmental rules, small divots of foam
rained off of the tank during ascent.

The phenomenon, called popcorning, was caused by
trapped bubbles; NASA solved the problem by venting
the foam with tiny holes, but it was a reminder, if
any was needed, that seemingly small changes can
have profound effects.

Ultimately, the accident board recommended that
NASA find ways to prevent any shedding of foam or
other debris. And NASA gained confidence during the
time between flights that it was making progress.

Among other things, it improved the training
processes for applying foam by hand.

At the Michoud tank assembly plant in Louisiana, an
observer monitors every worker spraying foam --
"for every sprayer there's a watcher, a second pair
of eyes," said June Malone, a NASA spokeswoman.

But the tank that flew with the Discovery last week
was made before the new procedures went into
effect, and NASA stopped short of requiring that
the ramps be redone, said a spokesman, Martin
Jensen.

After the Columbia accident board issued its
scathing report on the causes of the disintegration
-- especially a "broken safety culture" at NASA
that had grown complacent about all sorts of risks
-- another independent group was set up to monitor
NASA's progress in fulfilling the accident board's
recommendations.

That group, called the Stafford-Covey task force
after the two former astronauts who led it,
accepted NASA's argument that the PAL ramp did not
urgently require alteration.

At its final meeting in June, however, it also
found that NASA had failed to meet the goal of
eliminating all debris.

The group took issue with the way NASA determined
that the foam chunks that might still fall off the
tank were too small to cause critical damage.

And it criticized NASA's tendency to depend on
computer simulations when physical experiments
might yield more valuable data.

Ultimately, however, the group accepted NASA's
contention that it had raised the level of safety
in general.

A NASA engineer who works on tank safety issues
said other areas of foam shedding from the
Discovery's tank were even more troubling than the
PAL ramp loss -- especially a divot that popped
from the vicinity of the left-hand bipod strut, the
spot that shed the foam that brought down Columbia.

The loss of foam from that spot after so much work
to correct the problem, he went on, proves that the
problem is still far more complex than NASA
understands.

So the space agency is back to the drawing board.

Copyright (c) 2005 New York Times