[BigBobber]

There is an informative chart on Page 127 of the report that shows "the number of dings greater than one inch in diameter on the lower surface of the Orbiter after each mission". An eyball review of this chart shows the number of dings rising dramatcally starting with flight 86, which was in 1997.

From page 129:

"The foam loss problem on STS-87 was described as “pop-corning” because of the numerous popcorn-size foam par-ticles that came off the thrust panels. Popcorning has always occurred, but it began earlier than usual in the launch of STS-87. The cause of the earlier-than-normal popcorning (but not the fundamental cause of popcorning) was traced back to a change in foam-blowing agents that caused pres-sure buildups and stress concentrations within the foam. In an effort to reduce its use of chlorofluorocarbons (CFCs), NASA had switched from a CFC-11 (chlorofluorocarbon) blowing agent to an HCFC-141b blowing agent beginning with External Tank-85, which was assigned to STS-84. (The change in blowing agent affected only mechanically applied foam. Foam that is hand sprayed, such as on the bipod ramp, is still applied using CFC-11.)"

[bonesmccoy]

FINALLY!

I've been scanning the report for this stuff too.

Thanks for pointing to it.

CLINTON-GORE killed the shuttle program with their pro-environmental malarky.

[snopercod]

Thanks for finding that. I wasn't aware that the CFC-11 was still used locally at KSC. I'm not sure I believe it.

Regardless, the critical factor in adhering any kind of substance to aluminum (or anything else) is surface preparation. in the mid 90's when all the freon became taboo, NASA also changed the solvents used to clean things before bonding. They went from trichloroethane to "organic" solvents. If the CAIB didn't investigate this factor, then they were derelict in their duty.

This seems as good a time as any to add this to the record:

---

When we had to destack the Atlantis back in 1995 (pretty sure of the date) over the change in solvents, I got pissed and decided to do some checking.

First, I pulled B-5503, the SRB stacking procedure. Then, I pulled the specifications which it referenced. The first one of interest is MSFC-SPEC-2489 dated July 1995.

Only one products met the new spec., "REVILLE CLEANER, FORUMLA #02191", made by Diversey Dubois Intl., Inc. 255 E. 5th St., Cincinnati, OH 45202.

The spec. was obviously written so that only one product would meet it. It contains very specific flash points, initial boiling points, etc.

The new "Reville" cleaner was used to clean the SRB surfaces prior to the application of the J-Flap adhesive (per B5303 08-0161).

The second "green" cleaner was "CLEANER, ORGANIC WITH D-LIMONINE" per "MSFC-SPEC-2490" also July 1995. Same thing here. The spec was written so that only one product would comply. This was the "lemon-scented" PF DEGREASER made by P-T Technologies, 108 4th Ave., Safety Harbor, FL 34695.

I don't know exactly where this one was used, but I was told that it was a generic replacement for Trichloroehane, so this was probably the one used to prep the STS-107 ET prior to foam application.

"The cleaner shall be a clear liquid, free of foreign material and have a faint citrus odor as determined by visual inspection with the unaided eye (corrective lenses permitted)."

ROFL! The spec really says that.

I was also told that the original J-flap adhesive was "Morstik 132" which contained Trichlorethane, and that it was replaced with "Morstik 227", which was water-based. I don't have the specs on those.

Hope this helps.