Thanks for the link to the video.
I was a Shuttle engineer working for Rockwell out of Downey, CA for many years.
I have related the story below a couple of times, but I want to insure that future space historians have all the facts to determine what really happened with Columbia.
I was assigned to a team from Lab & Test Dept. to go to JSC and make them aware of the problems with the RCC leading edge on Columbia. I do not recall the year, but I think it was between 1995 and 1997.
Specifically, L&T found tiny craters on the RCC leading edge after one of Columbia’s flights. Note that the RCC was visually checked for problems using magnified images.
L&T concluded that the shock wave off the nose was impinging on the RCC (Reinforced Carbon-Carbon) leading edge resulting in very high heating rates in that area. At high enough temps, the oxygen molecules were crossing the glass coating and forming CO (carbon monoxide) which then outgassed causing the craters. They reproduced these results in the Lab.
L&T dubbed this process “de-densification” and showed that the RCC lost it’s structural integrity over time. After CT scanning, they learned that the RCC on Columbia had become so weak, you could poke your finger through it.
I was in that meeting at JSC and still have my notes on who was there.
I recall that at the time we were told, “RCC is $30,000 per square foot. There is NO money in the budget to replace the leading edge on Columbia”.
I left the program to work on the CSOC proposal.
Did they replace the RCC before the foam impact? I do not know and most of my contacts have retired.
Someone needs to look into this to find out if it was simply the foam or whether the weakened RCC was an accident waiting to happen.
Ice-laden foam was always a hazard and known risk. However, the loss of the Orbiter may have also been due to a budgetary oversight by the Agency.
I hope my information helps.
Thank you, that fits into the kind of stories I was hearing from some engineers. You may find this interesting:
Case Histories
Journal of Failure Analysis and Prevention
February 2006, Volume 6, Issue 1, pp 39-45
Failure analysis of the space shuttle Columbia RCC leading edge
M. Bykowski, A. Hudgins, R. M. Deacon, A. R. Marder
NASA’s Space Shuttle Columbia: Quick Facts
and Issues for Congress
Marcia S. Smith
Specialist in Aerospace and Telecommunications Policy
http://www.iwar.org.uk/news-archive/crs/20245.pdf
Corrosion Suggested in Shuttle Crash
http://www.nbcnews.com/id/3077582/#.VqpKGM_2Yu4
The Untold Story: Columbia Shuttle Disaster and Mysterious ‘Day 2 Object’
http://news.yahoo.com/untold-story-columbia-shuttle-disaster-mysterious-day-2-135349666.html
Timeline
http://www.iasa-intl.com/folders/shuttle/RCCdegTimeline.htm
Dynamic Impact Tolerance of Shuttle RCC Leading Edge
Panels Using LS-DYNA
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050220706.pdf
Materials Analysis: A Key to Unlocking the Mystery of the Columbia Tragedy
Brian M. Mayeaux, Thomas E. Collins, Gregory A. Jerman, Steven J. McDanels, Robert S. Piascik, Richard W. Russell, and Sandeep R. Shah
http://www.tms.org/pubs/journals/JOM/0402/Mayeaux-0402.html
Test and Analysis Correlation of Form Impact onto
Space Shuttle Wing Leading Edge RCC Panel 8
http://www.cs.odu.edu/~mln/ltrs-pdfs/NASA-2004-8lsdyna-elf.pdf
CASE STUDY: AXIOMATIC DESIGN OF THE SPACE SHUTTLE WING – LEADING
EDGE
http://www.axiomaticdesign.com/technology/icad/icad2004/icad-2004-35.pdf