Roger Boisjoly
Encyclopedia
Roger M. Boisjoly is a mechanical engineer, fluid dynamicist and an aerodynamicist who worked for Morton Thiokol, the manufacturer of the solid rocket booster
s for the Space Shuttle program. He is best known for raising objections to the launch of the Space Shuttle Challenger
the day before the loss of the spacecraft and its crew.
. Such a catastrophic event did occur less than a year later during the Space Shuttle Challenger disaster
.
This memo followed his investigation of a Solid Rocket Booster from a shuttle flight in January 1985
. During his investigation, he discovered that the first of a system of 2 O-Rings
had failed completely, and that some damage had been caused to the second O-Ring.
The O-Rings were two rubber rings that formed a seal between two sections of the Solid Rocket Booster
s. The sections of the boosters were joined using tang and clevis joints
and the rings were intended to seal the joint, while allowing for the inevitable movement between the sections under flight conditions. The pressure from within the booster pushed a fillet of putty into the joint, which forced the O-Ring into its seat. The rings never functioned according to design. They were supposed to sit in a groove and seal the joint between the sections of the booster. It was found, however, that the pressure of the burning rocket fuel caused the joints in the SRB's to flex during launch, opening a gap through which rocket exhaust could escape. As the joints flexed, the rings would come out of their grooves and move to a new position in the joint, a process called extrusion. The extruded ring would form a seal in this new position, but during the time it took for the ring to shift, the joint was unsealed and hot gasses could escape, a process called blow-by. These hot gasses would cause damage to the rings until the seal was achieved.
What Boisjoly's investigation showed was that the amount of damage to the O-Ring depended on the length of time it took for the ring to move out of its groove and make the seal, and that the amount of time depended on the temperature of the rings. Cold weather made the rubber hard and less flexible, meaning that extrusion took more time and more blow-by took place. He determined that if the O-rings were damaged enough they could fail.
If the second O-Ring had failed, Boisjoly realized, the results would almost certainly have been catastrophic with the complete loss of the shuttle and crew seemingly the only outcome. His investigation found that the first O-ring failed because of the low temperatures on the night before the flight had compromised the flexibility of the O-Ring, reducing its ability to form a seal. The temperature at launch had been only 10 °C – the coldest on record (until January 28, 1986). The first rubber O-ring had formed a partial seal, but not a complete one, but fortunately the second O-ring had held.
Boisjoly sent a memo, describing the problem to his managers, but was apparently ignored. It is true that Morton Thiokol were in discussions with NASA
with regards to a new contract (reportedly worth up to $1 Billion) and it is possible that the management were concerned that any issues discovered with the Solid Rocket Boosters may compromise the chances of the contract being renewed.
Following several further memos, a "task force" was set up – including Boisjoly – to investigate the matter, but after a month Boisjoly realized that the task force had no power, no resources and no management support.
Eventually, in late 1985 Boisjoly advised his managers that if the problem was not fixed, there was a distinct chance that a shuttle mission would end in disaster. No action was taken.
was confirmed for January 28, 1986, Boisjoly and his colleagues tried to stop the flight. Temperatures were due to be down to −1 °C overnight. Boisjoly felt that this would severely compromise the safety of the O-Ring, and potentially lose the flight.
The matter was discussed with Morton Thiokol management, who agreed that the issue was serious enough to recommend delaying the flight. They arranged a telephone conference with NASA
management and gave their findings. However, after a while, the Morton Thiokol managers asked for a few minutes off the phone to discuss their final position again. Despite the efforts of Boisjoly and others in this off-air briefing, the Morton Thiokol managers decided to advise NASA that their data was inconclusive. NASA asked if there were objections. Hearing none, the decision to fly the ill-fated STS-51L Challenger
mission was made.
Boisjoly's concerns proved correct. In the first moments after ignition, the O-rings failed completely and were burned away, resulting in the black puff of smoke visible on films of the launch. This left only a layer of aluminum oxide (a combustion product) to seal the joint. At 59 seconds after launch, buffeted by high-altitude winds, the oxide gave way. Hot gases streamed out of the joint in a visible torch-like plume that burned into the external hydrogen tank. At about 73 seconds, the adjacent SRB strut gave way and the vehicle quickly disintegrated.
Boisjoly was quite relieved when the flight lifted off, as his investigations had predicted that the SRB would explode during the initial take-off. Seventy-three seconds later he witnessed the shuttle disaster on television.
ordered a Presidential Committee to review the disaster, Boisjoly was one of the witnesses called. He gave accounts of how and why he felt the O-Rings had failed. After the Committee gave its findings, Boisjoly found himself shunned by colleagues and managers and he resigned from the company.
Boisjoly became a speaker on workplace ethics. He argues that the caucus called by Morton Thiokol managers, which resulted in a recommendation to launch, "constituted the unethical decision-making forum resulting from intense customer intimidation."
For his honesty and integrity leading up to and directly following the shuttle disaster, Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by the American Association for the Advancement of Science
.
When Boisjoly left Morton Thiokol, he took 14 boxes of every note and paper he received or sent in seven years. On May 13, 2010 he donated his personal memorandum- six boxes of personal papers, including memos and notes from Congressional testimony to Chapman University
in Orange, Ca
. Rand Boyd, the special-collections and archival librarian at Chapman's Leatherby Libraries, said the materials will be catalogued and archived. It will be about six months to a year before library visitors will be able to view the materials.
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
s for the Space Shuttle program. He is best known for raising objections to the launch of the Space Shuttle Challenger
Space Shuttle Challenger
Space Shuttle Challenger was NASA's second Space Shuttle orbiter to be put into service, Columbia having been the first. The shuttle was built by Rockwell International's Space Transportation Systems Division in Downey, California...
the day before the loss of the spacecraft and its crew.
O-Ring safety concerns
Boisjoly wrote a memo in July 1985 to his superiors concerning the faulty design of the solid rocket boosters that, if left unaddressed, could lead to a catastrophic event during launch of the Space ShuttleSpace Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
. Such a catastrophic event did occur less than a year later during the Space Shuttle Challenger disaster
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...
.
This memo followed his investigation of a Solid Rocket Booster from a shuttle flight in January 1985
STS-51-C
STS-51-C was the 15th flight of NASA's Space Shuttle program, and the third flight of Space Shuttle Discovery. It was also the first shuttle mission to deploy a dedicated United States Department of Defense payload, and as such many mission details remain classified...
. During his investigation, he discovered that the first of a system of 2 O-Rings
O-ring
An O-ring, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a disc-shaped cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.The O-ring...
had failed completely, and that some damage had been caused to the second O-Ring.
The O-Rings were two rubber rings that formed a seal between two sections of the Solid Rocket Booster
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
s. The sections of the boosters were joined using tang and clevis joints
Clevis pin
A clevis fastener is a three piece fastener system consisting of a clevis, clevis pin, and tang. The clevis is a U-shaped piece that has holes at the end of the prongs to accept the clevis pin. The clevis pin is similar to a bolt, but is only partially threaded or unthreaded with a cross-hole for a...
and the rings were intended to seal the joint, while allowing for the inevitable movement between the sections under flight conditions. The pressure from within the booster pushed a fillet of putty into the joint, which forced the O-Ring into its seat. The rings never functioned according to design. They were supposed to sit in a groove and seal the joint between the sections of the booster. It was found, however, that the pressure of the burning rocket fuel caused the joints in the SRB's to flex during launch, opening a gap through which rocket exhaust could escape. As the joints flexed, the rings would come out of their grooves and move to a new position in the joint, a process called extrusion. The extruded ring would form a seal in this new position, but during the time it took for the ring to shift, the joint was unsealed and hot gasses could escape, a process called blow-by. These hot gasses would cause damage to the rings until the seal was achieved.
What Boisjoly's investigation showed was that the amount of damage to the O-Ring depended on the length of time it took for the ring to move out of its groove and make the seal, and that the amount of time depended on the temperature of the rings. Cold weather made the rubber hard and less flexible, meaning that extrusion took more time and more blow-by took place. He determined that if the O-rings were damaged enough they could fail.
If the second O-Ring had failed, Boisjoly realized, the results would almost certainly have been catastrophic with the complete loss of the shuttle and crew seemingly the only outcome. His investigation found that the first O-ring failed because of the low temperatures on the night before the flight had compromised the flexibility of the O-Ring, reducing its ability to form a seal. The temperature at launch had been only 10 °C – the coldest on record (until January 28, 1986). The first rubber O-ring had formed a partial seal, but not a complete one, but fortunately the second O-ring had held.
Boisjoly sent a memo, describing the problem to his managers, but was apparently ignored. It is true that Morton Thiokol were in discussions with NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
with regards to a new contract (reportedly worth up to $1 Billion) and it is possible that the management were concerned that any issues discovered with the Solid Rocket Boosters may compromise the chances of the contract being renewed.
Following several further memos, a "task force" was set up – including Boisjoly – to investigate the matter, but after a month Boisjoly realized that the task force had no power, no resources and no management support.
Eventually, in late 1985 Boisjoly advised his managers that if the problem was not fixed, there was a distinct chance that a shuttle mission would end in disaster. No action was taken.
Challenger Disaster
Following the announcement that the Challenger missionSTS-51-L
STS-51-L was the twenty-fifth flight of the American Space Shuttle program, which marked the first time an ordinary civilian, schoolteacher Christa McAuliffe, had flown aboard the Space Shuttle. The mission used Space Shuttle Challenger, which lifted off from the Launch Complex 39-B on 28 January...
was confirmed for January 28, 1986, Boisjoly and his colleagues tried to stop the flight. Temperatures were due to be down to −1 °C overnight. Boisjoly felt that this would severely compromise the safety of the O-Ring, and potentially lose the flight.
The matter was discussed with Morton Thiokol management, who agreed that the issue was serious enough to recommend delaying the flight. They arranged a telephone conference with NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
management and gave their findings. However, after a while, the Morton Thiokol managers asked for a few minutes off the phone to discuss their final position again. Despite the efforts of Boisjoly and others in this off-air briefing, the Morton Thiokol managers decided to advise NASA that their data was inconclusive. NASA asked if there were objections. Hearing none, the decision to fly the ill-fated STS-51L Challenger
Space Shuttle Challenger
Space Shuttle Challenger was NASA's second Space Shuttle orbiter to be put into service, Columbia having been the first. The shuttle was built by Rockwell International's Space Transportation Systems Division in Downey, California...
mission was made.
Boisjoly's concerns proved correct. In the first moments after ignition, the O-rings failed completely and were burned away, resulting in the black puff of smoke visible on films of the launch. This left only a layer of aluminum oxide (a combustion product) to seal the joint. At 59 seconds after launch, buffeted by high-altitude winds, the oxide gave way. Hot gases streamed out of the joint in a visible torch-like plume that burned into the external hydrogen tank. At about 73 seconds, the adjacent SRB strut gave way and the vehicle quickly disintegrated.
Boisjoly was quite relieved when the flight lifted off, as his investigations had predicted that the SRB would explode during the initial take-off. Seventy-three seconds later he witnessed the shuttle disaster on television.
Career post-Challenger
After Ronald ReaganRonald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....
ordered a Presidential Committee to review the disaster, Boisjoly was one of the witnesses called. He gave accounts of how and why he felt the O-Rings had failed. After the Committee gave its findings, Boisjoly found himself shunned by colleagues and managers and he resigned from the company.
Boisjoly became a speaker on workplace ethics. He argues that the caucus called by Morton Thiokol managers, which resulted in a recommendation to launch, "constituted the unethical decision-making forum resulting from intense customer intimidation."
For his honesty and integrity leading up to and directly following the shuttle disaster, Boisjoly was awarded the Prize for Scientific Freedom and Responsibility by the American Association for the Advancement of Science
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...
.
When Boisjoly left Morton Thiokol, he took 14 boxes of every note and paper he received or sent in seven years. On May 13, 2010 he donated his personal memorandum- six boxes of personal papers, including memos and notes from Congressional testimony to Chapman University
Chapman University
Chapman University is a private, non-profit university located in Orange, California affiliated with the Christian Church . Known for its blend of liberal arts and professional programs, Chapman University encompasses seven schools and colleges: Lawrence and Kristina Dodge College of Film and Media...
in Orange, Ca
Orange, California
Southern California is well-known for year-round pleasant weather: - On average, the warmest month is August. - The highest recorded temperature was in 1985. - On average, the coolest month is December. - The lowest recorded temperature was in 1950...
. Rand Boyd, the special-collections and archival librarian at Chapman's Leatherby Libraries, said the materials will be catalogued and archived. It will be about six months to a year before library visitors will be able to view the materials.
External links
- Online as a case-study from the CWRU Online Ethics center, written by Boisjoly
- History of the Challenger accident from the NASA Marshall Spaceflight Center, discussing the O Ring and Boisjoly's objections to flight
- http://www.ocregister.com/news/boisjoly-248703-boyd-chapman.html, donating all of his personal papers