Replies

So much for the "Green Foam Formula" theory...

Had they left the asbestos in, even foam on foam would not have been an issue - or so I have heard.

They could could still loose it by parking in DC overnight.

Almost the same thinking messed up the Hubble. They were so sure the final tests done on it were off due to gravity warping the lens during the test that they made a simple mistake.

Some times you make mistakes even when you’re smart. You can’t assume you’re right because you’re smart.

Why fragile foam on a flight surface?
Why not better insulation *under* the surface?
They could have used the same material as the re-entry heat shield tiles, they insulate well and are light weight.
Well, it's moot now.

They showed cracks in the foam. Foam where no defects existed. It turns out that the thermal cycles associated with filling the tank could crack the foam, especially in areas where there were two or more layers of foam.

It's amazing they missed this. I thought of this as a pssiblity before I read the paragraph.

Does that mean the there was enough dimensional change in the diameter of the tank through heat and cold caused the foam to de-laminate?

Then we shut it down 3 years later.

This is off topic, but I’ve noticed this happen before. This topic “How we nearly lost Discovery” and the next article “Obama lawyer Angelo Genova tries to suppress & intimidate NJ conservative press & citizen journalist” don’t show up when I tried to look at the Discovery article on my Iphone. The articles above it “ You thought you knew Prostitutes.....” and the one below it “Swedish Stonehenge...” are there but the other two are not.

Why would the computer Freerepublic be different from the Iphone?

I thought the ET foam performed better with the freon-based foam than the new environmentally-friendly foam.

Shuttle Foam Loss Linked to EPA Regs
http://archive.newsmax.com/archives/ic/2005/7/28/93055.shtml
2005

(excerpt)
As recently as last month, NASA had been warned that foam insulation on the space shuttle’s external fuel tank could sheer off as it did in the 2003 Columbia disaster - a problem that has plagued space shuttle flights since NASA switched to a non-Freon-based type of foam insulation to comply with Clinton administration Environmental Protection Agency regulations.

Did PC Science Cause Shuttle Disaster?
http://www.foxnews.com/story/0,2933,77832,00.html
2003

(excerpt)
NASA is reconsidering whether tank foam debris caused the Columbia disaster. That’s quite a shift from days earlier when the foam was the “leading candidate” — an explanation that quickly became embarrassing.

Until 1997, Columbia’s external fuel tanks were insulated with a Freon-based foam. Freon is a chlorofluorocarbon (CFC) supposedly linked with ozone depletion and phased out of widespread use under the international treaty known as the Montreal Protocol.

Despite that the Freon-based foam worked well and that an exemption from the CFC phase-out could have been obtained, NASA succumbed to political correctness. The agency substituted an allegedly more eco-friendly foam for the Freon-based foam.

PC-foam was an immediate problem.

The first mission with PC-foam resulted in 11 times more damaged thermal tiles on Columbia than the previous mission with the Freon-based foam.

I thought of Eileen and her crew and how we had probably just killed them.

Not accurate at all.

One of the post-Columbia procedure changes was that the ISS would be used as a lifeboat in the event of damage that would preclude an orbiter returning safely to Earth, and that ALL shuttle missions were only going to the ISS (after much debate, and over the strenuous objections of the previous NASA Administrator, there was a waiver issued for the last Hubble servicing mission). The ISS was kept stocked up to capacity with consumables, and the Russians stood ready to launch extra Soyuz missions to bring the crew home. Nothing with the foam-shedding on the first post-Columbia return to flight would have impacted the ability of Discover to get to and dock with the ISS.

We shouldn’t have built the space shuttle, instead we should have instead concentrated on stamping out Saturn V’s at a “dime a dozen”....

We could have built the current space station in the mid 70’s with only a few launches. We could have had a moon base for what was blown on the space shuttle for crying out loud...

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2012-04-19

"ET" means "Space Shuttle External Tank"
"MMC" means the "Martin-Marietta Corporation
"SOFI" means "Sprayed On Foam Insulation"

I was a SOFI engineer for the ET who warned about low-tensile strength adhesion between the ET's aluminum skin and the foam.

I began work on the ET SOFI Program (Working for a Mike Jonnasson at the MMC Michoud New Orleans facility) in roughly 1984 ...

Standard Quality Assurance (QA) Test Procedures required about one-hundred "plug-pulls" on a completed External Tank (ET).

A "Plug Pull" was basically a one-inch diameter "foam core" that was pulled from the External Tank, to measure the tensile adhesive strength of the SOFI (foam) and the External tank's aluminum skin.

As I recall, the "passing requirement" was about 35 psi ... a value which had presumably been derived from calculations about how strong the foam's adhesion force had to be to properly "stick and hold" to the ET, especially during the Space Shuttle launch sequence.

These one-hundred or so "plug pulls" were always taken from the same standard "foam test locations" on the External Tank.

These areas included:

* Forward Ogive (LO2 tank at the top of the External Tank

* Intertank Section (Structual Cylinder at the Center of the External Tank

* LH2 (Hydrogen Tank) at the Lower Section of the External Tank

* Aft-Ogive Section (Hydrogen Tank) at the very bottom of the External Tank

The test data for the appromimately 30 ETs that MMC had already built (before I started working as a SOFI Engineer) was "suprisingly" stored on paper datasheets (stamped-off by NASA) in cardboard boxes in a dusty records archive at the MMC Michoud Facility in (eastern) New Orleans, where the ET was built.

I had just started studying "Statistical Process Control" (SPC) data analysis (X and R bar caharts, etc), and I also was familiar with computer programming using FORTRAN.

The "paper data sheets" that MMC and NASA had archived were basically useless in the state that I had discovered them.

So I embarked upon a two-stage course of action.

1) place data from the "paper sheets" into a (mainframe) computer database, into data files that could be read by the FORTRAN computer language

2) write an "Expert System" in FORTRAN that would read SOFI test data, from essentially "all" the External Tanks ever built, and then analyize that data, to wit:

2-A) statistical values (average, max, min, standard deviations) of all SOFI foam "plug-pull" tests from all ETs built

2-B) predict specific areas of the ET where the SOFI manufacturing process was deficient (ie. the foam didn't stick well to the ET)

2-C) provide all of this "analyzed data" to MMC and NASA Quality Assurance so that (potential problems could be fixed)

It took about six months to do all of this ... while I continued my daily work as a Manufacturing Engineer in the "Advanced Manufacturing Technology" (AMT) department, managed by Terry Hibbard, with my immediate supervisor a great (honest) man, Mike Johnasson.

Mike Johnasson allowed me to do this special project, presumably knowing where it might lead ...

Looking back, I really admire Mike for that ...

Finally, my data is collected and analyzed, and it appears to point to about six (6) areas on the External Tank that (after 30-plus tanks built) ... have a general tendency for "weak" SOFI tensile adhesion to the ET's aluminum skin ... less than 35-psi required by NASA specifications ...

I present this data to Mike Johnasson, who then (later) takes me to AMT's Terry Hibbard to look at the conclusions.

However, it's decided that there's "no great story" here ... and Management apprears to want to close the issue out ...

I protest, of course (still being a young 33 years old) ... warning explictly that SOFI debris from the ET could damage the Orbiter's Thermal Tiles during the launch sequence, and then possibly have the Orbiter destroyed during re-entry.

The gentle ridicule and cynicism from MMC was difficult to deal with with ...

However, we had just lost the "Challenger" only two years ago ... so I fought like a bulldog ...

Suddenly, one-afternoon ... perhaps 3-4 months later ... I was summoned one afternoon to Ron Heiter's Executive Office (MMC Director), where the following people (as I recall) were present:

1) MMC Legal Counsel

2) Terry Hibbard and Mike Johnasson

3) Ron Heiter, MMC Director (sitting at his large desk).

Ron Heiter told me that a NASA aerodynamics engineer in Huntsville (Marshall Space Flight Center) had analyzed damage to the Space Suttle Orbiter's Thermal-Tiles ... for a large number of launches ...

That analysis had pointed towards SOFI debris (weakly adhered to the ET's aluminum skin) falling-off during the Shuttle launch sequence ...

and then that SOFI debris crashing into the Orbiter's Thermal-Tiles at high-speed ...

damaging, and in some cases, cracking and even knocking the Thermal-Tiles from the Space Shuttle Orbiter.

To everyone's suprise, the analysis used air-flow areodynamic methods to calculate where that SOFI debris was coming from on the External Tank ...

and the areas that he predicted ... corresponded "exactly" to the six-odd areas of "weak foam" that I had predicted (completely independently).

Ron Heiter thanked me for my efforts, and presented me with a $ 500 gift certificate to Campo's Furniture, which I subsequenntly used to purchase a brand-new washing machine and dryer for family.

Of course, the issue remained: "How Do We Fix This" ?

I was (not suprisingly) soon transferred AWAY from the SOFI Engineering area ...

and then terminated (fired, as Mitt Romney likes to say) ...

I took my case directly to NASA's offices, both in New Orleans, and then in Hunstville, Alabama.

No one even bothered to talk to me.

That's my story.

Respecfully.

Douglas A. Coggeshall, Aerospace Mechanical Engineer

CEAI@Engineering-Excellence.US

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Dont discount the green foam...the shuttle started flying in 81..how many years with no foam loss..then did not change there process they change the foam formula and they started having problem...he just gives the mechanism that impacted the new but not older foam