NASA grounds the Shuttle indefinitely - but no one wants to talk about the insulation

WELCOME INSTAPUNDIT READERS! (... and thanks, Glenn)

Also many thanks to the others who have linked and tracked back to this post.  Your links and comments are appreciated.

More information in this post as well.

Here's a link to my Shuttle news roundup, updated daily.

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The New York Times reports that NASA has officially announced that the Space Shuttle will be grounded indefinitely - until they figure out how to keep the exterior foam insulation from peeling off the gigantic fuel tank that is the main piece of the Shuttle's launch assembly.

The Columbia and its crew were lost because a 1.67-pound piece of insulating foam that had fallen off the external tank during liftoff crashed through the leading edge of the shuttle's left wing. The resulting hole admitted superheated gases during the shuttle's fiery re-entry into the atmosphere on Feb. 1, 2003.

That chunk fell from an area of hand-applied foam called the bipod arm ramp. The ramp's insulating foam surrounded the struts connecting the tank to the orbiter, and were originally designed to prevent ice from forming and becoming a debris hazard. But NASA had noticed that the bipod arm ramp tended to shed foam and decided to redesign it. They planned to replace it after the Columbia flight.

... In the incident described here on Wednesday, the new piece of foam - a hat-shaped chunk as much as 33 inches across at the widest part and 14 inches at the narrow part - sheared off another ramp on the external tank. It is known as the protuberance air load ramp, which NASA abbreviates as the PAL ramp, and was designed to minimize crosswise airflow and turbulence around cable trays and lines used to pressurize the external tank. The new piece is slightly smaller than the briefcase-size piece that hit the Columbia, Mr. Hale said.

... Mr. Parsons and Mr. Hale said there were other surprising examples of lost foam - including divots several inches long that popped out of "acreage foam," which is applied robotically and had been considered to be free of shedding problems.

But here is what no one seems to be talking about - the problems with foam peeling and breaking off the main fuel tank are relatively new.  In 1997, NASA bent to pressure from environmental groups and began using a new type of foam on the main fuel tank.

Why all the fuss?  Because the traditional foam insulation, the product that had been specified in the 1970 Shuttle designs, the product that was used up until 1997, was made by injecting polymer with chlorofluorocarbons -- "freon" -- compounds whose use was severely limited under the 1991 Montreal Protocol.  With the adoption of this protocol by the U. S., the Environmental Protection Agency set target dates for major industries to phase out the use of freon.

After the new foam was used on Columbia mission STS-87 in November 1997, post-flight examination of the craft found that 308 of the special heat-absorbent ceramic tiles that cover the Shuttle's outer skin were damaged.  The average number of damaged tiles for previous missions was 40.  NASA engineers immediately suspected that the new insulating foam was breaking loose, but NASA supervisors were apparently more interested in impressive, successfully-completed missions than in adequate mission safety.  The peeling foam was written off as a negligible risk. 

The irony of this is that in 2001, the EPA exempted NASA from enforcement of its freon regulations because an audit determined that the amount of freon used by NASA was minuscule.  But apparently NASA was more concerned with public relations and with making sure that their policies received a nod of approval from environmental groups.  NASA's official report on the Columbia disaster cited a change in the foam application process -- and not the change in the foam itself -- as the most sensible reason for the foam to start peeling off.

When the Rogers Commission released their official report on the Challenger disaster in 1987, there was one member of the panel who did not sign it.  That person was Noble laureate physicist Richard P. Feynman.  He released his own statement after the commission's hearings were published, which concluded,

For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.

Environmentalists, maybe, but certainly not the laws of physics.

Hopefully NASA will reconsider Dr. Feynman's timeless observation again as they try to solve the problem of peeling CFC-free Space Shuttle fuel tank foam.

Either that, or maybe they could think about investing their time and energy in a space vehicle that is not dependent on 30-year-old technology, and that actually costs less to operate than an a roughly equivalent but non-reusable payload-carrying vehicle.  That would be real progress.

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Here's more on this subject in an August 2004 post by Paul at WizBang.

Sissy Willis was having trouble tracking back here, so Sissy, here is a link to your related post.  If you haven't read her excellent writing or shared in her cat fancies,then you should check out her blog.

...

PS - Readers may wonder why I made scant mention of the 1986 Challenger explosion in this post.  Many have speculated that the Challenger explosion could have been prevented by the use of an asbestos-containing putty to fill the now-infamous solid rocket booster o-ring seals, and that environmental concerns also led to the Challenger disaster. Like the myth claiming that the World Trade Center could have been saved if only there had been more asbestos-containing fireproofing present, the Challenger o-ring asbestos claims are false.  The design was flawed from the beginning, and using the asbestos putty as a "chewing gum" patch was not a real solution.  Here is a link to everything you need to know about the Challenger o-ring failure.

Also, with regard to my description of NASA's freon use as "miniscule" - I could not find a source that listed the number of pounds of freon used by NASA in the late 1990's, but the environmental impact study by the EPA seemed to conclude that NASA was meeting their usage goals, and that NASA's freon use was small enough so that its effect on the environment was considered negligible.  Therefore, by industrial standards it had to be pretty small.

UPDATE: Found NASA's freon targets here.  The 2001 usage goal was less than 100 gallons, which on an industrial scale is pretty insignificant.

FINAL ADDENDUM:  I feel that I need to clarify a few things about "freon."  Freon is a trademark registered to DuPont, but like "Kleenex" and "Coke" (the soft drink) it has come to represent a group of related products -- chemical compounds that primarily contain carbon and hydrogen, and chlorine and fluorine.  These chemicals are also known as halogenated hydrocarbons or chlorofluorocarbons (CFC's). 

Freon is primarily used by consumers, in a compressed gas form, as a refrigerant.  Its discovery made artificial refrigeration inexpensive and safe.  Using Freon meant that manufacturers of refrigerant systems no longer had to use toxic compounds such as methyl chloride, ammonia, or sulfur dioxide.  Imagine having those in your home refrigerator!

Chlorofluorocarbon compounds are also used as solvents.  They are ideally suited for cleaning metal parts where contamination must be stringently avoided, because CFC solvents such as freon 113 are extremely aggressive cleaning agents and leave practically no residue.  NASA's White Sands Testing Facility was able to reduce the actual amount of freon 113 use to 65 gallons in 2001, which was well within their stated goal of 100 gallons or less.  White Sands dropped their freon 113 usage requirements completely in 2002 and 2003.  In 2004, White Sands was awarded the 2004 Stratospheric Ozone Protection Award by the EPA.

Although the use of freon as a cleaning agent and its use in the manufacture of polymeric foam are two different applications, it still stands to reason that NASA certainly had enough merit with the EPA (by virtue of their solvent freon elimination program) to at least try using the older, safer freon-containing insulation foam again on the Shuttle's external fuel tank.  There was certainly enough data to suggest that the new foam posed a serious safety hazard.

A few more links:

NASA's response to the Columbia investigative report

EPA Section 608 Final Rule, regarding the use of freon

Comments

[Bebeaux (at DOUBLE TOOTHPICKS)]

Congrats on the Instalanche, Mike!

[Ryon]

Excellent posting, Mike.

Keep on spreading the Good Noise!

[Sissy Willis]

I wish my comments and/or trackbacks would show up here. What gives? http://sisu.typepad.com/sisu/2005/07/this_is_the_rev.html

[paul]

Great post, scary thoughts indeed re the NASA mgt turning a blind eye for PC...

[Sissy Willis]

Hi, Mike --

Thanks for the nice mention. I see that my trackback and earlier comment did finally show up. Patience is not one of my virtues. :)

[Leland]

"But here is what no one seems to be talking about - the problems with foam peeling and breaking off the main fuel tank are relatively new. "

I disagree with this. Foam peeling off was not new at all. Not even new for STS-87. STS-1 had 300 tiles replaced (source CAIB figure 6.1-7). True, a change was made to the chemical make-up of the foam, but that began with STS-84. STS-87 just marked an unusual number of foam debris strikes. The problems on STS-87 were tracked to the change in foam, but that doesn't account for STS-7, STS-32R, STS-50, STS-52, and STS-62, which all had the same bipod ramp foam loss similar to that which doomed STS-107.

A lot of people at NASA have complained about the foam change. However, the facts do not support simply reverting to the old formula as a solution. The CAIB thoroughly investigated this issue. I linked to their report. If interested in reading about foam, start at page 121.

(Leland - thanks for the info. -Mike)

[Steve Herr]

I suggest that you read the Columbia Accident Investigation Board's report
on the accident, specifically chapter three:

"Most of the external tank is insulated with three types of spray-on foam
NCFI 24-124 is a polyisocyanurate applied with blowing agent HCFC 141b
hydrochloroflourocarbon, is used on most areas of the liquid hydrogen and
liquid oxygen tanks. NCFI 24-57, another polyisocyanurate foam applied with blowing agent HCFC 141b hydrochloroflourocarbon, is used on the lower liquid hydrogen tank dome. BX-250, a polyurethane foam applied with CFC-11
chlorofluorocarbon was used on domes, ramps, and areas where the foam is
applied by hand. The foam types used changed after External tank 93, which
was used on STS-107, but these changes were beyond the scope of this
section."

see http://caib.nasa.gov/news/report/pdf...s/chapter3.pdf Scroll
down to page 51 (page numbering from the beginning of the report, not of the chapter), starting at the bottom of the left hand column and
continuing on to the top of the right hand column.

CFC-11 is one of the group of chemicals using the Freon trade name. And note that STS-107 was the Columbia's last flight, and that the foam chunk that hit the leading edge of the wing came off the left bipod ramp would have been the Freon-based foam.

Therefore, the facts run directly counter to the thesis of the claim here - it was a Freon based foam that caused the damage, not an inferior substitute.

Yes, tanks with reformulated foam were used starting with ET (external tank) #86 and ET #-87. ET#87 had significantly higher shedding than the average for the prior 40 or so tanks - the fabled "ten times worse" for dings on the bottom side tiles greater than 1". See http://caib.nasa.gov/news/report/pdf/vol4/part04.pdf and look on page 21 for a graph of the number of tile dings based on external tank number. I have read that the flight with tank #87 did what is referred to as the "heads-up roll" early on in the flight for the first time on any mission, and that changed the areas that were under significant air pressure during ascent. Also, be aware that when you look at the graph on page 21, that there is not an exact correlation between tank number and the type of foam used - tank #93 on the ill-fated Columbia mission had the old foam formula on it. Tanks 1-85(?) were original formula, tanks 86 through 100 were a mix of new and old, and tanks after #100 are probably all new formulations. From the graph, you can see that the later tanks with the new formulation that have flown (tanks 100-120) seem to cause less damage than the earlier tanks, as a rule. Thus, it would be incorrect to conclude that the freon-free foam causes more shedding than the freon-based formula, the correct conclusion is that on average, the new formulations cause fewer dings. It would be nice if NASA provided this graph and provided notes which tanks had what formulas and what flight configurations were used (ie, heads up roll).

Unless us armchair analysts have access to all the information about all the flights and become experts on foam formulations and their relative strengths, while we may be able to speculate, we shouldn't delude ourselves to thinking we can come to a conclusion about the causes of a complex accident like the Columbia tragedy. As the CAIB report said, even NASA does not know and understand all the factors involved in the foam shedding problem.

But to blame greenies for banning freon and thus causing teh Colubia tragedy is completely off-base and is not supported in any way by the facts.

[thebizofknowledge]

I stumbled across your blog while I was doing some online research. I still have not forgotten the previous Shuttle tragedies and can only hope that NASA will, to the best of its ability, only put people up there that it feels confident it can bring back safely.

[Zoneaire]

i hope all goes well with the NASA shuttel

[Zoneaire]

i hope the shuttel takes off safely