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.
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.
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: