Good, but frightening article from Newsmax. Environmentalist wackos are responsible.

http://www.newsmax.com/showinside.shtml?a=2003/2/4/174925

Clinton Environmental Policy Sabotaged the Shuttle

Thank fussy "environmentalists" from the Clinton administration for the substandard but politically correct foam that NASA thinks caused the Columbia disaster.

"NASA engineers have known for at least five years that insulating foam could peel off the space shuttle's external fuel tanks and damage the vital heat-protecting tiles that the space agency says were the likely 'root cause' of Saturday's shuttle disaster," the left-of-center Philadelphia Inquirer noted today in an article by Knight Ridder News Service.

So why was such a crummy substance used in such a crucial capacity, with the lives of seven astronauts at stake? Because "environmentalists" fretting about their theory of human-caused "global warming" wanted to use it.

In a 1997 report, NASA mechanical systems engineer Greg Katnik "noted that the 1997 mission, STS-87, was the first to use a new method of 'foaming' the tanks, one designed to address NASA's goal of using environmentally friendly products. The shift came as the U.S. Environmental Protection Agency was ordering many industries to phase out the use of Freon, an aerosol propellant linked to ozone depletion and global warming," Knight Ridder reported.

Insulation is sprayed on the shuttle's tanks to keep the super-cooled hydrogen and oxygen fuels at the correct temperature.

Before the P.C. new insulation was used, about 40 of the spacecraft's 26,000 ceramic tiles would sustain damage in missions. However, Katnik reported that NASA engineers found 308 "hits" to Columbia after a 1997 flight.

A "massive material loss on the side of the external tank" caused much of the damage, Katnik wrote in an article in Space Team Online.

He called the damage "significant." One hundred thirty-two hits were bigger than 1 inch in diameter, and some slashes were as long as 15 inches.

Most frighteningly, some slashes cut three-quarters of the way into the 2-inch-deep tiles, near the ship's aluminum skin, which burns at only 350 degrees. More than 100 tiles had to be replaced - 11 times more than in a previous mission that had used foam made with politically incorrect Freon.

"As recently as last September, a retired engineering manager for Lockheed Martin, the contractor that assembles the tanks, told a conference in New Orleans that developing a new foam to meet environmental standards had 'been much more difficult than anticipated,'" Knight-Ridder wrote.

The engineer, who helped design the thermal protection system, said that switching from the Freon foam "resulted in unanticipated program impacts, such as foam loss during flight."

PC bullshit strikes again!

Well, look at the bright side.  At least polar bear cubs aren't getting too much UV. [rolleyes]

Freon fulfills both roles I believe. Freon 11 is used as a propellant and Freon 12 is the refrigerant.

But either way, another fuck up on the EPA's eternal quest for significance.

So, while "they" chose to eliminate the environmental hazards associated with the foam, 'they" somehow chose to ignore the tons of chlorine liberated every time they fire those solid fuel boosters?

It's not the Freon that's the problem, it's the free chlorine produced when it breaks down. The main oxidizer in one booster's solid fuel probably puts more chlorine into our atmosphere than all the foam ever put on all the shuttles made.

Space walks have been done before for many reasons; if someone (didn't one on-the-ground engineer even suspect it would have been worth it?) had a hunch there was a problem, why didn't the flight controllers get one of the crew to go out & have a closer look?

The Columbia's crew perished because of a long string of errors.

And here I was thinking I was the only one that noticed that Freon isn't a propellent.  Although, in all honesty, it IS a gas, and under pressure it *could* be used as a propellent.

Freon 12 (dichloro-difluoromethane) has been used as a propellent but also as the foaming gas in polyurethane foam systems.

The switch from an ether-based, chloroflourocarbon foamed/propelled foam to an ester-based, in-situ CO2 foamed polyurethane allowed moisture to penetrate the interface between the foam and the tank.  Adhesion was compromised when the resultant shrinkages associated with the cryogenic fill of the tanks.

Now this is known.  What I want to know is how much has ground level UV radiation increased from supposed "ozone holes"?  All the Aussies I talk to claim its significant but what do they  know other than what their wacko's tell them.  After all, they think Foster's is a good beer.

Back to science.  I know the extinction coefficients for both oxygen and ozone.  I know the frequency spreads.  The numbers just do not add up because ozone, even in its precious layer, is only found in parts per million.  Oxygen is hunderds of thousands of parts per million, about 210,000 ppm last ime I checked.  Beer's Law states absorption is extinction coefficient multiplied by molar concentration.  

Anyone with hard data? I cannot find any.

First, formaldehyde based foams were banned (these sucked anyway because of shrinkage). That is besides the point, just alittle history.

I smell more BS.

I remember switching to non-Freon urethane two-component products around 1994. The first prototype mixtures were aweful. They more more picky with application temperature and component ratio. Even expansion was more of an issue than adhesion with the older foams.
I had worked with these products for several years. Now-a-days the non-froen foam is just as good.


I would submit that if the chemical adhesion properties of the foam in question can cause such consequence that it isn’t the damn hippies or the foam’s fault.  There is not sufficient difference between the Freon based and non-Freon based urethane foams. In other words, if the non-freon foam's adhesion is a liability: the design is marginal.

Both foams are photochemically reactive. Maybe they can blame it on the sun.

Idiots.
As a design Engineer I am sometimes effected by the "green movement" i.e. some of my designs must use lead-free components. These components require a higher reflow temperature during manufacture. Some components simply cannt withstand that kind of peak temperature.

I do not substitute one device for another device that impacts the performance of the product in order to maintain it's lead-free attributes. If I must maintain a "green" design, I build more robustness into the design to compensate. This adds cost but the design specifcations and robustness are not sacrificed.

Wrongo buddy, there is a freaking WORLD of difference between ester and ether based foams on moisture resistance.

Formaldehyde?  That's Urea-formaldhyde.  Totally different polymer but still a thermoset like urethane.

A urethane is a condensation polymer formed from a polyol (multiple hydroxyl alcohol) with a disocyanate(a hydrocarbon with two CN radicals)...HO-R-OH + CN-R-NC.  that is the simmple part.  Cross-linkage makes any polymer more durable etc...most urethanes use either a ether or ester structure with either the polyol or the disocyanate to effect cross-linkage.

The problem with the ester based systems is gernerally poor moisture resistance since an ester can hydrate.

Furthermore, the phase-out of CFC's from polyurethane foam happened in the 1980's.  Tanks made with the old system were white.  The orange ones are the new system.

You see!  That's what I love about this site!

An old country boy like me posts an article with a bunch of big words that I caint hardly cipher.  

Then along comes these here PHDs with all these big words like "Urea-formaldhyde", and "disocyanate to effect cross-linkage", and "photochemically reactive".

Whooo-eeee.  Hot dang!  I'm gettin an edumachation  and havin fun all at the same exact time!

Ain't life grand on AR15.com?

I did not claim any chemical relation to Formaldehyde based product........I just recalled the problems with it. The application equipment was much the same. Why? Because like you said, it was a thermoset.

You seem to have some insite to the chemical nature.  I worked with isocyanurates. The freon was subbed for a non-CFC substitute and I claim from experience that the adhesion remained mostly constant between the two.

I sprayed MILLIONS of square feet of this stuff CFC and non CFC. I did one million square feet in a few months.
We switched to non-freon product around 1994, I know for sure it was not earlier than 1992.

The color of the barrels were no indication of the CFC content in the product. Usually the iso was red and the resin was brown (or the other way around).

Edit to add: I sprayed alot of product on Metal buildings for DISA shakers.............liquid Nitrogen cryro tanks, crete, etc so adhesion qualities were very important.

Thats was the RTV for the tiles

"When you are unemployed, sitting in the dark and shivering, and your space shuttle lies in burned chunks on the ground, thank an environmentalist!"

Mea Culpa.  Freon is a class of CFC's and HCFC's.  R22 has only a tiny fraction of the "ozone depleting potential of R12.  R22 was permitted to be used as a propellent until the mid 1990's.  R134 can still be used as a propellent as it has no Cl

Not Correct.

The first two external tanks were white  beacuse the surface was painted with a white latex paint. NASA then realized that they could save another 600 pounds of launchable payload weight by simply not painting the tanks.

The Enviro friendly foam switch did not occur until 1997, about 15 years after the first "orange" tank flew without paint.

SG

Not sure what you mean by extinction coefficients and frequency spreads when it comes to the ozone depletion story.  I was skeptical about the ozone depletion by freon so I looked at the primary, peer-reviewed source literature.  A brief summary:

The suspicion that Freon and other chlorinated halogens (like Halon) goes back to the mid 1970's documented in an article by Molina and Rowland in Nature (vol. 249, p. 810).  The connection between Freon and the ozone hole was made in the 1980's when the mechanism for destroying the ozone was determined.  Basically,
Freon plus UV light gives a free chlorine ion which combines with ozone and converts it to O2.  Several thousand ozone molecules are destroyed by each ion.  Here is where it gets tricky.  The reason that the Antarctic hole grows in the southern winter is that the concentration of NO2, which slows the ozone destroying reaction, freezes out in the -70C temperature of the polar stratosphere.  It is explained in a Scientific American article Sept 1989, p. 70-79.  The reactions described above were discovered by flying U2s in the stratosphere over the south pole and sampling the gases there.

As far as whether this is all hippy histeria, this stuff is peer-reviewed which means that other scientists look to rip your evidence and conclusions up. They try to duplicate your results and if they can't they will try to discredit you.  Believe me I know from personal experience, you have to have your science ducks in a row to propose a hypothesis or theory.  Remember Cold Fusion? That was quickly shot down by the scruitiny of the science community.

Now, even good science can be co-opted by the Left.  You have to look at the evidence.

[LOLabove][b] Now there's my type of intellectual response. All you friggin' Freon chemists, just chill out! (no pun intended. i think.)[/b]

I know all about the reactions.  That science I do NOT question.  I question something more basic, namely what is the realtionship between ozone layer concentration and ground-level UV?  To date, this has ALWAYS been the primary concern yet the numbers cannot be found.

I emboldened [i]duplicate results[/i] because I have not seen the evidence that points to the source of ClO (its not Cl, that's too reactive) in the stratosphere.  Furthermore, the photoreactivity of CFC's is not well documented, at least as required for formation of the ClO portion of the theory.

I have seen all of the articles you presented, thaks for referencing them.  There still are unanswered questions which if answered, could make some of the scientific community look quite foolish.  This is not the first time such bad conclusions have been reached.  Look at the medical community, specifically pyloric bacteria cause of some ulcers and antibiotic therapy for this problem is more effective than acid reducers like Tagamet (which surprise, is now a non-perscription drug).

Now back to focus:

I don't mean to beat a dead horse here but its getting suspicious.  
I found the data! [url]http://oz.physast.uga.edu/get_account.html[/url]

First of all, they will not let me download the data because I do not belong to a organization they recognize (email to follow).  The research is funded by my tax dollars yet they want to keep it secret?  WhY?

Then I see data, if I could get it, has been "corrected".  Why?  
To fit their conclusions?  Nice science.  I guess its selected peer review.

Data correction procedures?  I understand the need but the link isn't finished.  Hmmm, how are we to believe data "corrected" by an unknown procedure?
[url]http://oz.physast.uga.edu/data_corrections.html[/url]

I think I need to make a little call to a well-known conservative writer as this is just too rich.  I bet if I dig any deeper, members of the Communist Party will be found.

Keith,
Have to agree with you on medical research.  But that is something the public "understands" so the rush to announce results that are in reality half-baked is the usual result.  I don't bother listening to any more "X" causes cancer studies.

If you can't get the data, I could give it a shot.  As far as "corrected" data, perhaps they are normalizing the data to a standard atmosphere?  As you say, linkee no workee so who knows what the correction really is for.  If this work is government funded a report should come out every year and a final report when the project is done.  You might do searches for recent publications by Rives or Meltzer.

It is nice to have a discussion that does not need IBTL or "I'd hit it" to boost post counts.

IBTL [;D][;D][;D][;D]

Medical research is just as heavily peer reviewed as scientific.  The interesting part is how perscription drugs are made over the counter after the application is deemed less than efficient.  Tagamet and ulcers.  Rogaine and MPB.  Claritin and allergies.  

So far, I have not received an account with the FTP site and no explaination either.  I am guessing if I had a Greenpeace email addy, I probably would have a response by now.  Its quite irritating to see "Organization" a required field for the account verification.  Of course I made one up and its quite unique.  I am monitoring the virtual world for uses of this organization to see what pops up.  Trust me, I will find something.