Remembering the Space Shuttle Challenger: Was it Really an Asbestos Substitute that did in the O-rings and, Ultimately, caused the tragedy? My Research.

I first posted my full research project discussing this Internet myth during January 2022 in the blog located at https://theasbestosblog.com/?p=9723. The full blown 75 page research paper with footnotes and bibliography can be read at https://theasbestosblog.com/wp-content/uploads/2022/01/Space-Shuttle-Challenger-Thesis-1282022.pdf.

If you are interested in the topic but do not want to read the entire scholarly analysis, please find a plain language 10 page analysis (without footnotes or a bibliography) at https://theasbestosblog.com/wp-content/uploads/2023/01/Summary-Research-Challenger-2023-Blog.pdf. It really is a fascinating topic with the issue framed as:

“My initial goal in researching the January 28, 1986 Challenger tragedy was to solve the internet myth on whether it was caused, or contributed to, by an asbestos substitute that failed.  This is a significant issue as the Challenger situation continues to be used as a teaching experience for leadership, ethics, communication, engineering, and group think classes.  The Challenger accident remains sufficiently popular that Netflix aired a documentary in 2020 that focused on the effect of the cold temperature on the O-rings that failed in the right-hand solid rocket booster.  When I decided to return to school in 2021, the involvement of the asbestos-containing putty that was designed to protect those O-rings seemed to be the perfect topic for me to research.  As it turns out, when it comes to the asbestos or the potential asbestos putty substitute, we have all been asking the wrong question.” 

Initially, let’s talk risk in the space shuttle program. It was always going to be present, but budget constraints masked the actual risks being taken. As stated in my paper:

“Even with the importance of risk control, the budget constraints for the shuttle program required NASA to manage those risks “in a tight fiscal environment” with restrictive funding.   As stated by Roger Launius, a Chief Historian for NASA, “[t]he bare-bones funding strategy for the program forced NASA to take short-cuts.”   In a 1988 survey of NASA employees, 80% responded “agree” or “strongly agree” to the statement: “Cost constraints have forced us to cut corners in carrying out our programs.” “

Ouch!

As to the Challenger related call the night prior to the launch:

“On January 27, 1986, thirty-four highly trained professionals at three locations participated in a phone discussion on whether the Challenger should launch the following day given the anticipated cold weather in Florida.  The fifteen people at NASA Marshall Space Flight Center, fourteen at Morton-Thiokol in Brigham City, Utah, and five at the Kennedy Space Center in Cape Canaveral, Florida were looking at faxed copies of the handwritten and typed analysis. After all, there were no laptops, no internet, and email was yet to be invented.

With NASA on hold, several Thiokol engineers and scientists included Brian Russell, Roger Boisjoly, Arnie Thompson, Jerry Burns, Bob Ebeling, and Kyle Speas were making their case to the Company’s four vice presidents not to launch the space shuttle solid rocket boosters at less than 53 degrees Fahrenheit because of concerns about the field joints.  Those vice presidents were all technically trained in engineering or math with, between them, 140 years of work experience.  As such, they would listen to their technical people, but make their own considered decision.  Finally, the discussion led to a decision. The Thiokol management, under pressure from NASA, stated that Thiokol had re-evaluated its original position not to launch, and that Thiokol now supported the client’s desire to proceed even given the anticipated cold.  During the launch the next day, the aft field joint on the right hand solid rocket booster failed 73 seconds into the flight, leading to the tragic loss of the crew and all equipment.  From the launch photographs, a puff of black smoke from the right hand booster aft section is clearly visible immediately after ignition.  And suddenly, the world as known by everyone involved with that phone call had changed.”

As to the cause of the tragedy, we all know that the two O-rings failed in the cold weather. When you dig into that failure, the underlying issue is why the asbestos-containing vacuum putty which was used to protect those O-rings did not do its job. Was the then recent change from a putty manufactured by Fuller-O’Brien to one manufactured by Randolph somehow the difference? Was it an asbestos substitute that failed as claimed by many on the Internet and in some articles? Good questions. In summary:

“Was the failure caused, or contributed to, by an asbestos substitute that failed?  That is the wrong question as there was no asbestos substitute.  Both the original Fuller-O’Brien putty and the replacement Randolph putty contained the same asbestos related specifications.  However, the correct question is whether the change in the putties themselves may have caused the failure.  The answer to that question, based on the statistical analysis undertaken at my request by Thiokol retiree Jerry Burn is that “Randolph Putty had 3.1 times more Gas Path occurrences on Field Joints than Fuller O’Brien.” The critical nature of this increase in risk cannot be overstated.   The higher the probability of a gas path, the higher the probability of an O-ring failure, and the higher the probably of a joint failure like the one which caused the Challenger tragedy.  To be clear, gas paths in the joints were formed during assembly, and not created by cold temperature at launch.  Rather, the cold launch temperature affected the O-rings such that they could not seal in time as the cold caused them to be harder and therefore less responsive.  This was a race between 5800 degree Fahrenheit propellant exhaust through a gas path that was formed during assembly in comparison with the O-ring timing to seal at the moment of the launch.  On this day, the exhaust won.

Given the passage of time, we will never know the precise differences in the putties that caused or contributed to the increase in gas paths.  However, one potential contributing factor is that the asbestos fibers in the replacement putty were thicker and longer, and therefore weaker, than the asbestos fibers used in the original putty.  The difference in diameter and length identified by visual observation was noted on page 8 in the March 8, 1983 report analysis by Thiokol chemist Frank Bares, and confirmed by him during our interview. However, that testing and putty comparison also showed significant differences in the non-asbestos material properties.“

In addition:

“The additional gas paths caused by the Randolph putty exposed two weaknesses that were the secondary causes of the tragedy.  The first was the decision-making process by NASA, including its focus on day-to-day issues and priorities without resolving or fully understanding the joint related safety issues arising during the critical first 122 seconds of the flight.  The record is replete with NASA ignoring warnings prior to the January 27, 1986 launch discussion meeting.  Further, NASA then changed the rules by requiring its vendors (both Thiokol on the solid rocket motors and Rockwell on the orbiter) to prove that a cold weather launch outside of the relevant known databases was unsafe instead of presuming such a launch to be unsafe absent acceptable data supporting the safety.  This was the ultimate mistake on January 27, 1986 and the day of launch.  As often heard at NASA, “In God we Trust, all others bring data.”

The second weakness was the flawed field joint design that had previously been masked by the rheological qualities of the Fuller-O’Brien putty.  In summary, because of the Fuller-O’Brien putty material flow and better consistency during changing humidity and temperatures, NASA and Thiokol did not realize the full extent of the flaws in the original field joint design until after the January 28, 1986 tragedy and their work to re-design the field joints for future shuttle flights.  Without a gas path forming during the assembly process, there is no field joint failure.  With a gas path having formed, a great number of unknowns came into play.”

Such a tragedy and loss of life. Let me know if you found this discussion interesting and informative either by leaving a comment or sending me an email at TheAsbestosBlog@gmail.com. Thank you. Marty.