Roger Boisjoly had over a quarter-century's experience in the aerospace industry in 1985 when he became involved in an improvement effort on the O-rings which connect segments of Morton Thiokol's Solid Rocket Booster, used to bring the Space Shuttle into orbit. Boisjoly has spent his entire career making well-informed decisions based on his understanding of and belief in a professional engineer's rights and responsibilities. For his honesty and integrity leading up to and directly following the shuttle disaster, Roger Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by...
Roger Boisjoly had over a quarter-century's experience in the aerospace industry in 1985 when he became involved in an improvement effort on the O-rings which connect segments of Morton Thiokol's Solid Rocket Booster, used to bring the Space Shuttle into orbit. Boisjoly has spent his entire career making well-informed decisions based on his understanding of and belief in a professional engineer's rights and responsibilities. For his honesty and integrity leading up to and directly following the shuttle disaster, Roger Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by the American Association for the Advancement of Science.
Mr. Boisjoly died of cancer in St. George, Utah on Jan. 6, 2012. He spent his final years offering workshops and lectures on changing workplace ethics for numerous universities and civic groups.
For more information see this rememberance on NPR.
January 28, 1986. Two video clips of the Challenger Explosion from CNN: "Reagan honors shuttle crew (1986)" and "NASA remembers Challenger".
In January of 1987, nearly a full year after the Challenger exploded, Roger Boisjoly spoke at MIT about his attempts to avert the disaster during the year preceding the Challenger launch. According to the Report of the Presidential Commission on the Space Shuttle Challenger Accident, "evidence pointed to the right solid rocket booster as the source of the accident." In 1985 Boisjoly began work to improve the O-ring seals which connect segments of Morton Thiokol's solid rocket booster. Boisjoly was frustrated with the slow progress and the lack of management attention to the seal task force. He spoke about the events leading up to the disaster in this address.
Boisjoly's discussion of the Challenger Disaster is separated into seven sections. Each section is then followed by some possible responses. To see discussion of any response, click on the link to it. Supporting material is also provided. You may want to consult some of it in deciding what you would have done in Roger Boisjoly's place at each stage of the story.
This page and supporting pages were originally created by Jagruti S. Patel and Phil Sarin.
Roger Boisjoly presented this material first in a talk in January 1987 at MIT. The first publication was in the volume of conference papers for the 1987 Annual Meetings of the American Society of Mechanical Engineers in fall 1987.
Boisjoly, Roger M. 1987.
Ethical Decisions -- Morton Thiokol and the Space Shuttle Challenger Disaster.
American Society of Mechanical Engineers Annual Meetings.
Texto en Español
The final flight readiness assessment chart read as follows:
Conclusion: STS-51C consistent with erosion data base. Low temperature enhanced probability of blow-by.
STS-51C experienced worst case temperature change in Florida history. STS-51E could exhibit same behavior. Condition is acceptable.
STS-51E field joints are acceptable for flight.
These conclusions were accepted and the flight was certified ready for launch.
Later, I met with Arnie Thompson to discuss the blow-by scenario and the effect of cold temperature on O-ring resiliency, which is the ability of the seal to restore itself to a round shape when the squeeze on the seal is removed. Arnie proposed that subscale lab tests be conducted which would provide us with assessment data. The resiliency testing was performed in March and showed that low temperature was a problem. The results indicated that the seals would lift off their sealing surfaces for several seconds at 75 degrees Fahrenheit and in excess of 10 minutes at 50 degrees Fahrenheit. This data was discused with Morton Thiokol engineering management but was thought to be too sensitive by them to release.
Another post flight inspection occurred in June 1985 at Morton Thiokol in Utah. This time a nozzle joint from Flight 51B, which flew on April 29, 1985, was found to have a primary seal eroded in three places over a 1.3 inch length up to a maximum depth of 0.171 inches, and the secondary seal in the same joint was eroded 0.032 inches. It was postulated that this primary seal had never sealed during the full two minutes of flight.
My former concerns now escalated because if this same scenario happened in a field joint, the secondary seal could also be compromised especially during a low temperature launch. A Flight Readiness Review presentation was prepared for Flight 51F, which was scheduled for launch on July 29, 1985. The presentation was given to NASA at MSFC on July 1, 1985, with an additional presentation on the overall status of the booster seals given the next day. The preliminary results of the O-ring resilience testing in March were presented for the first time during this meeting. All O-ring test samples were 0.280 inch diameter and compressed to 0.040 inches with a decompression distance of 0.030 inches at a 2-inch-per-minute rate as compared with a flight rate of approximately 3.2 inches per minute. The results showed that the seals did not lose contact at 100 degrees Fahrenheit; lost contact for 2.4 seconds at 75 degrees, and lost contact in excess of 10 minutes at 50 degrees. Test results also indicated that a 0.295-inch diameter seal lost contact for 2 to 3 seconds at 50 degrees, which meant that the 0.295-inch diameter seal performance at 50 degrees was similar to the performance of a 0.28-inch diameter seal at 75 degrees. Everyone on the program for the first time was now aware of the influence of low temperature on the joint seals.
My concern increased once again due to the lack of attention being given to this problem.
The bench tests showed that temperature can adversely affect the resiliency, and therefore the effectiveness, of the O-rings, yet management at Thiokol and NASA shows no interest in planning a design change. What general courses of action are reasonable for an engineer in this sort of situation?