Rogers Commission Report
Encyclopedia
The Rogers Commission Report was created by a Presidential Commission
charged with investigating the Space Shuttle Challenger disaster
during its 10th mission, STS-51-L
. The report, released and submitted to President Ronald Reagan
on 9 June 1986, both determined the cause of the disaster that took place 73 seconds after liftoff, and urged NASA to improve and install new safety features on the shuttles and in its organizational handling of future missions.
s sealing the aft field joint on the right solid rocket booster, causing pressurized hot gases and eventually flame to "blow by" the O-ring and make contact with the adjacent external tank, causing structural failure. The failure of the O-rings was attributed to a design flaw, as their performance could be too easily compromised by factors including the low temperature on the day of launch.
, saying that it was seriously flawed. The report found evidence that NASA managers did not know of Thiokol's initial concerns about the effects of the cold on the O-rings, and did not understand that Rockwell
viewed the large amount of ice present on the pad as a constraint to launch. It concluded that:
In one example, early tests resulted in some of the booster rocket's O-ring
s burning a third of the way through. These O-rings provided the gas-tight seal needed between the vertically stacked cylindrical sections that made up the solid fuel booster. NASA managers recorded this result as demonstrating that the O-rings had a "safety factor" of 3. Feynman incredulously explains the magnitude of this error: a "safety factor" refers to the practice of building an object to be capable of withstanding more force than it will conceivably be subjected. To paraphrase Feynman's example, if engineers built a bridge that could bear 3,000 pounds without any damage, even though it was never expected to bear more than 1,000 pounds in practice, the safety factor would be 3. If, however, a 1,000 pound truck drove across the bridge and it cracked at all, the safety factor is now zero: the bridge is defective.
Feynman was clearly disturbed by the fact that NASA management not only misunderstood this concept, but in fact inverted it by using a term denoting an extra level of safety to describe a part that was actually defective and unsafe. Feynman continued to investigate the lack of communication between NASA's management and its engineers, and was struck by management's claim that the risk of catastrophic malfunction on the shuttle was 1 in 105; i.e., 1 in 100,000. Feynman immediately realized that this claim was risible on its face; as he described, this assessment of risk would entail that NASA could expect to launch a shuttle every day for the next 274 years while suffering, on average, only one accident. Investigating the claim further, Feynman discovered that the 1 in 105 figure was stating what they claimed that the failure rate ought to be, given that it was a manned vehicle, and working backwards to generate the failure rate of components.
Feynman was disturbed by two aspects of this practice. First, NASA management assigned a probability of failure to each individual bolt, sometimes claiming a probability of 1 in 108; that is, one in one hundred million. Feynman pointed out that it is impossible to calculate such a remote possibility with any scientific rigor. Secondly, Feynman was bothered not just by this sloppy science but by the fact that NASA claimed that the risk of catastrophic failure was "necessarily" 1 in 105. As the figure itself was beyond belief, Feynman questioned exactly what "necessarily" meant in this context—did it mean that the figure followed logically from other calculations, or did it reflect NASA management's desire to make the numbers fit?
Feynman suspected that the 1/100,000 figure was wildly fantastical, and made a rough estimate that the true likelihood of shuttle disaster was closer to 1 in 100. He then decided to poll the engineers themselves, asking them to write down an anonymous estimate of the odds of shuttle explosion. Feynman found that the bulk of the engineers' estimates fell between 1 in 50 and 1 in 100. Not only did this confirm that NASA management had clearly failed to communicate with their own engineers, but the disparity engaged Feynman's emotions. When describing these wildly differing estimates, Feynman briefly lapses from his damaging but dispassionate detailing of NASA's flaws to recognize the moral failing that resulted from a scientific failing: he was clearly upset that NASA presented its clearly fantastical figures as fact to convince a member of the public, schoolteacher Christa McAuliffe
, to join the crew. Feynman was not uncomfortable with the concept of a 1/100 risk factor, but felt strongly that the recruitment of laypeople required an honest portrayal of the true risk involved.
Feynman's investigation eventually suggested to him that the cause of the Challenger disaster was the very part to which NASA
management so mistakenly assigned a safety factor. The O-rings were rubber rings designed to form a seal in the shuttle's solid rocket boosters, preventing the rockets' super-heated gas from escaping and damaging other parts of the vehicle. Feynman suspected that despite NASA's claims, the O-rings were unsuitable at low temperatures and lost their resilience when cold, thus failing to expand and maintain a tight seal when rocket pressure distorted the structure of the solid fuel booster. Feynman's suspicions were corroborated by General Kutyna, also on the commission, who cunningly provided Feynman with a broad hint by asking about the effect of cold on O-ring seals after mentioning that the temperature on the day of the launch was far lower than had been the case with previous launches: below freezing at 28 or 29 Fahrenheit (−2.2 to −1.6 °C
); previously, the coldest launch had been at 53 °F (12 °C).
Feynman's investigations also revealed that there had been many serious doubts raised about the O-ring seals by engineers at Morton Thiokol
, which made the solid fuel boosters, but communication failures had led to their concerns being ignored by NASA management. He found similar failures in procedure in many other areas at NASA, but singled out its software development for praise due to its rigorous and highly effective quality control procedures - then under threat from NASA management, which wished to reduce testing to save money given that the tests had always been passed.
Based on his experiences with NASA's management
and engineers, Feynman concluded that the serious deficiencies in NASA management's scientific understanding, the lack of communication
between the two camps, and the gross misrepresentation of the shuttle's dangers, required that NASA take a hiatus from shuttle launches until it could resolve its internal inconsistencies and present an honest picture of the shuttle's reliability. However, Feynman soon found that, while he respected the intellects of his fellow Commission members, they universally finished their criticisms of NASA with clear affirmations that the Challenger disaster should be addressed by NASA internally, but that there was no need for NASA to suspend its operations or to receive less funding. Feynman felt that the Commission's conclusions misrepresented its findings, and he could not in good conscience recommend that such a deeply flawed organization as NASA should continue without a suspension of operations and a major overhaul. His fellow commission members were alarmed by Feynman's dissent, and it was only after much petitioning that Feynman's minority report was included at all. In fact, Feynman was so critical of flaws in NASA's "safety culture" that he threatened to remove his name from the report unless it included his personal observations on the reliability of the shuttle, which appeared as Appendix F. In the appendix, he stated:
Feynman later wrote about the investigation in his 1988 book What Do You Care What Other People Think?
. The second half of the book covers the investigation and the issues between science and politics.
Feynman later reported that, although he had believed he was making discoveries about the problems at NASA on his own, he eventually realized that NASA or contractor personnel, in an apparent effort to anonymously focus attention on these problem areas, had carefully led him to the evidence which would support the conclusions on which he would later report.
on September 29, 1988 with Discovery
. Reforms to NASA
procedures were enacted which attempted to preclude another occurrence of such an accident, and the Shuttle program would continue without serious incident until the Space Shuttle Columbia disaster
on February 1, 2003.
Presidential Commission (United States)
In the United States, a Presidential Commission is a special task force ordained by the President to complete some special research or investigation...
charged with investigating 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...
during its 10th mission, STS-51-L
STS-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...
. The report, released and submitted to President Ronald Reagan
Ronald 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....
on 9 June 1986, both determined the cause of the disaster that took place 73 seconds after liftoff, and urged NASA to improve and install new safety features on the shuttles and in its organizational handling of future missions.
Commission members
- William P. RogersWilliam P. RogersWilliam Pierce Rogers was an American politician, who served as a Cabinet officer in the administrations of two U.S. Presidents in the third quarter of the 20th century.-Early Life :...
, former secretary of state - Neil ArmstrongNeil ArmstrongNeil Alden Armstrong is an American former astronaut, test pilot, aerospace engineer, university professor, United States Naval Aviator, and the first person to set foot upon the Moon....
, the first human to walk on the moon - David C. Acheson
- Eugene E. CovertEugene E. CovertEugene Edzards Covert was an aeronautics specialist born in Rapid City, South Dakota credited with the world's first practical wind tunnel magnetic suspension system, and was a member of the Rogers Commission...
- Richard P. FeynmanRichard FeynmanRichard Phillips Feynman was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics...
, winner of the 1965 Nobel Prize in PhysicsNobel Prize in PhysicsThe Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and... - Robert B. Hotz
- Donald J. KutynaDonald J. KutynaGeneral Donald Joseph Kutyna is a retired United States Air Force Officer. He was commander in chief of the North American Aerospace Defense Command and the United States Space Command from 1990 to 1992, and commander of Air Force Space Command at Peterson Air Force Base, Colorado from 1987 to 1990...
, Air Force general with experience in ICBMs - Sally K. RideSally RideSally Kristen Ride is an American physicist and a former NASA astronaut. Ride joined NASA in 1978, and in 1983 became the first American woman—and then-youngest American, at 32—to enter space...
, the first American woman in space - Robert W. Rummel
- Joseph F. Sutter
- Arthur B. C. Walker, Jr
- Albert D. Wheelon
- Chuck YeagerChuck YeagerCharles Elwood "Chuck" Yeager is a retired major general in the United States Air Force and noted test pilot. He was the first pilot to travel faster than sound...
, retired Air Force general, the first person to break the sound barrierSound barrierThe sound barrier, in aerodynamics, is the point at which an aircraft moves from transonic to supersonic speed. The term, which occasionally has other meanings, came into use during World War II, when a number of aircraft started to encounter the effects of compressibility, a collection of several...
in level flight - Alton G. Keel, Jr.Alton G. Keel, Jr.Alton Gold Keel, Jr. is an American engineer, diplomat, and businessman.Keel attended the University of Virginia, where he earned a bachelor of science in aerospace engineering in 1966 and a Ph.D. in 1970...
O-ring failure
The commission found that the Challenger accident was caused by a failure in the O-ringO-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...
s sealing the aft field joint on the right solid rocket booster, causing pressurized hot gases and eventually flame to "blow by" the O-ring and make contact with the adjacent external tank, causing structural failure. The failure of the O-rings was attributed to a design flaw, as their performance could be too easily compromised by factors including the low temperature on the day of launch.
"An accident rooted in history"
More broadly, the report also determined the contributing causes of the accident. Most salient was the failure of both NASA and its contractor, Morton Thiokol, to respond adequately to the design flaw. The Commission found that as early as 1977, NASA managers had not only known about the flawed O-ring, but that it had the potential for catastrophe. This led the Rogers Commission to conclude that the Challenger disaster was "an accident rooted in history."Flawed launch decision
The report also strongly criticized the decision making process that led to the launch of ChallengerSpace Shuttle Challenger launch decision
The Space Shuttle Challenger launch decision was the decision-making process that led to the launch of the Space Shuttle Challenger on January 28, 1986 despite inclement weather conditions and the warnings of many engineers working both for NASA and for NASA contractors Morton Thiokol and Rockwell...
, saying that it was seriously flawed. The report found evidence that NASA managers did not know of Thiokol's initial concerns about the effects of the cold on the O-rings, and did not understand that Rockwell
Rockwell International
Rockwell International was a major American manufacturing conglomerate in the latter half of the 20th century, involved in aircraft, the space industry, both defense-oriented and commercial electronics, automotive and truck components, printing presses, valves and meters, and industrial automation....
viewed the large amount of ice present on the pad as a constraint to launch. It concluded that:
Role of Richard Feynman
One of the commission's best-known members was theoretical physicist Richard Feynman. His style of investigating with his own direct methods rather than following the commission schedule put him at odds with Rogers, who once commented, "Feynman is becoming a real pain." During a televised hearing, Feynman famously demonstrated how the O-rings became less resilient and subject to seal failures at ice-cold temperatures by immersing a sample of the material in a glass of ice water. Feynman's own investigation reveals a disconnect between NASA's engineers and executives that was far more striking than he expected. His interviews of NASA's high-ranking managers revealed startling misunderstandings of elementary concepts. One such concept was the determination of a safety factor.In one example, early tests resulted in some of the booster rocket's O-ring
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...
s burning a third of the way through. These O-rings provided the gas-tight seal needed between the vertically stacked cylindrical sections that made up the solid fuel booster. NASA managers recorded this result as demonstrating that the O-rings had a "safety factor" of 3. Feynman incredulously explains the magnitude of this error: a "safety factor" refers to the practice of building an object to be capable of withstanding more force than it will conceivably be subjected. To paraphrase Feynman's example, if engineers built a bridge that could bear 3,000 pounds without any damage, even though it was never expected to bear more than 1,000 pounds in practice, the safety factor would be 3. If, however, a 1,000 pound truck drove across the bridge and it cracked at all, the safety factor is now zero: the bridge is defective.
Feynman was clearly disturbed by the fact that NASA management not only misunderstood this concept, but in fact inverted it by using a term denoting an extra level of safety to describe a part that was actually defective and unsafe. Feynman continued to investigate the lack of communication between NASA's management and its engineers, and was struck by management's claim that the risk of catastrophic malfunction on the shuttle was 1 in 105; i.e., 1 in 100,000. Feynman immediately realized that this claim was risible on its face; as he described, this assessment of risk would entail that NASA could expect to launch a shuttle every day for the next 274 years while suffering, on average, only one accident. Investigating the claim further, Feynman discovered that the 1 in 105 figure was stating what they claimed that the failure rate ought to be, given that it was a manned vehicle, and working backwards to generate the failure rate of components.
Feynman was disturbed by two aspects of this practice. First, NASA management assigned a probability of failure to each individual bolt, sometimes claiming a probability of 1 in 108; that is, one in one hundred million. Feynman pointed out that it is impossible to calculate such a remote possibility with any scientific rigor. Secondly, Feynman was bothered not just by this sloppy science but by the fact that NASA claimed that the risk of catastrophic failure was "necessarily" 1 in 105. As the figure itself was beyond belief, Feynman questioned exactly what "necessarily" meant in this context—did it mean that the figure followed logically from other calculations, or did it reflect NASA management's desire to make the numbers fit?
Feynman suspected that the 1/100,000 figure was wildly fantastical, and made a rough estimate that the true likelihood of shuttle disaster was closer to 1 in 100. He then decided to poll the engineers themselves, asking them to write down an anonymous estimate of the odds of shuttle explosion. Feynman found that the bulk of the engineers' estimates fell between 1 in 50 and 1 in 100. Not only did this confirm that NASA management had clearly failed to communicate with their own engineers, but the disparity engaged Feynman's emotions. When describing these wildly differing estimates, Feynman briefly lapses from his damaging but dispassionate detailing of NASA's flaws to recognize the moral failing that resulted from a scientific failing: he was clearly upset that NASA presented its clearly fantastical figures as fact to convince a member of the public, schoolteacher Christa McAuliffe
Christa McAuliffe
Christa McAuliffe was an American teacher from Concord, New Hampshire, and was one of the seven crew members killed in the Space Shuttle Challenger disaster....
, to join the crew. Feynman was not uncomfortable with the concept of a 1/100 risk factor, but felt strongly that the recruitment of laypeople required an honest portrayal of the true risk involved.
Feynman's investigation eventually suggested to him that the cause of the Challenger disaster was the very part to which 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 so mistakenly assigned a safety factor. The O-rings were rubber rings designed to form a seal in the shuttle's solid rocket boosters, preventing the rockets' super-heated gas from escaping and damaging other parts of the vehicle. Feynman suspected that despite NASA's claims, the O-rings were unsuitable at low temperatures and lost their resilience when cold, thus failing to expand and maintain a tight seal when rocket pressure distorted the structure of the solid fuel booster. Feynman's suspicions were corroborated by General Kutyna, also on the commission, who cunningly provided Feynman with a broad hint by asking about the effect of cold on O-ring seals after mentioning that the temperature on the day of the launch was far lower than had been the case with previous launches: below freezing at 28 or 29 Fahrenheit (−2.2 to −1.6 °C
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
); previously, the coldest launch had been at 53 °F (12 °C).
Feynman's investigations also revealed that there had been many serious doubts raised about the O-ring seals by engineers at Morton Thiokol
Thiokol
Thiokol is a U.S. corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems...
, which made the solid fuel boosters, but communication failures had led to their concerns being ignored by NASA management. He found similar failures in procedure in many other areas at NASA, but singled out its software development for praise due to its rigorous and highly effective quality control procedures - then under threat from NASA management, which wished to reduce testing to save money given that the tests had always been passed.
Based on his experiences with NASA's management
Management
Management in all business and organizational activities is the act of getting people together to accomplish desired goals and objectives using available resources efficiently and effectively...
and engineers, Feynman concluded that the serious deficiencies in NASA management's scientific understanding, the lack of communication
Communication
Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...
between the two camps, and the gross misrepresentation of the shuttle's dangers, required that NASA take a hiatus from shuttle launches until it could resolve its internal inconsistencies and present an honest picture of the shuttle's reliability. However, Feynman soon found that, while he respected the intellects of his fellow Commission members, they universally finished their criticisms of NASA with clear affirmations that the Challenger disaster should be addressed by NASA internally, but that there was no need for NASA to suspend its operations or to receive less funding. Feynman felt that the Commission's conclusions misrepresented its findings, and he could not in good conscience recommend that such a deeply flawed organization as NASA should continue without a suspension of operations and a major overhaul. His fellow commission members were alarmed by Feynman's dissent, and it was only after much petitioning that Feynman's minority report was included at all. In fact, Feynman was so critical of flaws in NASA's "safety culture" that he threatened to remove his name from the report unless it included his personal observations on the reliability of the shuttle, which appeared as Appendix F. In the appendix, he stated:
It appears that there are enormous differences of opinion as to the"For a successful technology," Feynman concluded, "reality must take precedence over public relations, for nature cannot be fooled."
probability of a failure with loss of vehicle and of human life. The
estimates range from roughly 1 in 100 to 1 in 100,000. The higher
figures come from the working engineers, and the very low figures from
management. What are the causes and consequences of this lack of
agreement? Since 1 part in 100,000 would imply that one could put a
Shuttle up each day for 300 years expecting to lose only one, we could
properly ask "What is the cause of management's fantastic faith in the
machinery? .. It would appear that, for whatever purpose, be it for internal or
external consumption, the management of NASA exaggerates the
reliability of its product, to the point of fantasy."
Feynman later wrote about the investigation in his 1988 book What Do You Care What Other People Think?
What Do You Care What Other People Think?
"What Do You Care What Other People Think?": Further Adventures of a Curious Character is the second of two books consisting of transcribed and edited oral reminiscences from American physicist Richard Feynman. It follows Surely You're Joking, Mr. Feynman!The book presents his life as a series of...
. The second half of the book covers the investigation and the issues between science and politics.
Feynman later reported that, although he had believed he was making discoveries about the problems at NASA on his own, he eventually realized that NASA or contractor personnel, in an apparent effort to anonymously focus attention on these problem areas, had carefully led him to the evidence which would support the conclusions on which he would later report.
Result
The investigation and corrective actions following the Challenger accident caused a 32-month hiatus in shuttle launches: the next mission was STS-26STS-26
STS-26 was the 26th NASA Space Shuttle mission and the seventh flight of the Discovery orbiter. The mission launched from Kennedy Space Center, Florida, on 29 September 1988, and landed four days later on 3 October. STS-26 was declared the "Return to Flight" mission, being the first mission after...
on September 29, 1988 with Discovery
Space Shuttle Discovery
Space Shuttle Discovery is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on August 30, 1984, until its final landing during STS-133 on March 9, 2011...
. Reforms to 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...
procedures were enacted which attempted to preclude another occurrence of such an accident, and the Shuttle program would continue without serious incident until the Space Shuttle Columbia disaster
Space Shuttle Columbia disaster
The Space Shuttle Columbia disaster occurred on February 1, 2003, when shortly before it was scheduled to conclude its 28th mission, STS-107, the Space Shuttle Columbia disintegrated over Texas and Louisiana during re-entry into the Earth's atmosphere, resulting in the death of all seven crew members...
on February 1, 2003.
External links
- Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident — the Rogers Commission report on the accident
- Hearing on the Space Shuttle Accident and the Rogers Commission Report. Pages: 219 (14.2 MB) U.S. Senate Committee on Commerce, Science and Transportation, Subcommittee on Science, Technology and Space. Date: 99th Congress, 2nd Session, February 18, June 10 and 17, 1986. See also GPO Challenger index page.
- http://history.nasa.gov/rogersrep/v2appf.htm - Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident, Appendix F - Personal Observations on Reliability of Shuttle by R. P. Feynman