09 Sep Review of the Space Shuttle Challenger Disaster
3-page single space assessment/review of the Space Shuttle Challenger Disaster. This should include:
Please include at least 3 sources
–Introduction to the Space Transportation System
–The technical problem and reason
–The ethical challenge
-Your recommendations
Notes are attached.
Primary Causes of Engineering Disasters
| human factors (including both 'ethical' failure and accidents) design flaws (many of which are also the result of unethical practices) materials failures extreme conditions or environments, and, most commonly and importantly combinations of these reasons |
A study* conducted at the Swiss Federal Institute of Technology in Zurich analyzed 800 cases of structural failure in which 504 people were killed, 592 people injured, and millions of dollars of damage incurred. When engineers were at fault, the researchers classified the causes of failure as follows:
* M. Matousek and Schneider, J., (1976) Untersuchungen Zur Struktur des Zicherheitproblems bei Bauwerken, Institut für Baustatik und Konstruktion der ETH Zürich, Bericht No. 59, ETH.
Causes of Failures
Insufficient knowledge …………………………. 36% Underestimation of influence ………………… 16% Ignorance, carelessness, negligence ……….. 14% Forgetfulness, error ……………………………… 13% Relying upon others (without sufficient control)… . 9%
Objectively unknown situation …………………. 7% Imprecise definition of responsibilities ……… 1% Choice of bad quality ………………………………. 1% Other ……………………………………………………. 3%
Engineering Ethics Space Shuttle Challenger Accident
Front Row ( L to R): : Michael J. Smith, Francis R. “Dick” Scobee, Ronald E. McNair;
Back Row ( L to R): Ellison S. Onizuka, S. Christa McAuliffe, Gregory B. Jarvis, and Judith A. Resnik.
January 28, 1986
Space Transportation System
Technical Issues
Ethical Issues
Space Transportation System (STS)
Solid Rocket Boosters
(SRB)
Two – 149 ft x 12ft dia
Liquid Fuel
External Tank (ET)
154 ft x 27.6 ft dia
Shuttle Orbiter (122 ft long 48 ft wide)
Launch Weight
4.5 Million Lbs
SRB Propellant Weight
1.1 Million Lbs (Solid)
ET Propellant Weight
1.65 Million Lbs (Liquid)
Orbiter returns as a glider
Thermal Protection System
Primary System- Ceramic Tiles ( app 30,000)
High Temperature Reusable Insulation (HRSI)
Leading Edges- Reinforced Carbon-Carbon (RCC)
ET- Covered in Foam Insulation (Pre-Launch)
Alternative to HRSI in later flight Fibrous Refractory Composite Insulation (FRCI)
Program History
First Launch – April 12, 1981
Last Launch – July 8, 2011
Total Missions -135
Two Accidents
Challenger – January 28, 1986 (All aboard lost)
Columbia – February 1, 2003 (All aboard lost)
Flight Statistics
Challenger Accident
0.678 sec after lift off – a puff of smoke
From aft field joint of right SRB
58 sec later fire around circumference
of aft field joint
72 – 73 sec. catastrophic failure
Accident Analysis
Challenger
Tank Explosion during ascent
Cause: O-ring leakage from SRB to fuel tank
Contributing Causes -1. Launch outside the proven temperature envelop, 2. Flawed go-no-go decision process, 3. Management
Corrective actions: SRB redesign, improved communications between technologist and program management
The O-Rings
The O-Rings
Redesigned Field Joints
Sequence of Events
Discovering Leaks in the Primary Seal
January 1985: Post-flight hardware inspection of
Flight 51C (Discovery) revealed evidence that hot Roger Boisjoly
combustion gases had compromised the primary seals on two field joints.
Briefing to higher management at Marshall Space Flight Center (MSFC) in Huntsville, Alabama, which included the observations and an explanation of the scenarios that caused the seal erosion and hot gas blow-by.
Morton Thiokol asked to prepare a detailed presentation as part of the Flight Readiness Review for Flight 51E, which was scheduled for launch in April 1985.
This presentation was given in February 1986 at three successively higher-level review boards with refinements in contents made at each level emphasizing that the lower-than-usual launch temperature was responsible for such a large witness of hot gas blow-by, but NASA management insisted that this position be softened for the final review board.
http://www.onlineethics.org/Topics/ProfPractice/Exemplars/BehavingWell/RB-intro/RB1-1.aspx
A Management Decision Overrides an Engineering Recommendation
Teleconference with Kennedy Space Center (KSC) and MSFC started with a history of O-ring damage in field joints.
Data was presented showing a major concern with seal resiliency and the criticality of this on the ability to seal. Two engineers Boijosly and Arnie Thompson presented their arguments for a no-launch.
The presentation ended with the recommendation by the VP Engineering not to launch below 53o F.
This was not well received by NASA. Joe Kilminster, the Vice President of Space Booster Programs (Thiokol), was then asked by NASA for his launch decision. He did not recommend launch, based upon the engineering position just presented.
Then Larry Mulloy of NASA (who was at KSC) asked George Hardy of NASA (who was at MSFC) for his launch decision. George responded that he was appalled at Thiokol's recommendation but said he would not launch over the contractor's objection. Then Larry Mulloy spent some time giving his interpretation of the data with his conclusion that the data presented was inconclusive.
Just as he finished his conclusion, Joe Kilminster asked for a five-minute off-line caucus to re-evaluate the data, and as soon as the mute button was pushed Thiokol’s general manager, Jerry Mason, said in a soft voice, "We have to make a management decision.”
During the closed managers' discussion, Jerry Mason asked in a low voice if he was the only one who wanted to fly. The discussion continued, then Mason turned to Bob Lund, the vice-president of engineering, and told him to take off his engineering hat and put on his management hat. The decision to launch resulted from the yes vote of only the four senior executives. The engineers were excluded from both the final decision and the vote poll.
The telecon resumed, and Joe Kilminster (VP of Space Programs) read the launch support rationale from a handwritten list and recommended that the launch proceed. NASA promptly accepted the recommendation to launch without any probing discussion and asked Joe to send a signed copy of the chart.
The Morton Thiokol Manager of Booster Program at Cape Canaveral Alan MacDonald declined to sign it.
Main People
Boijosly, Arnie Thompson – Engineers, Thiokol
Bob Lund, VP Engineering, Thiokol
Joe Kilminster, VP Space Booster Program, Thiokol
Jerry Mason, GM Thiokol
Alan McDonald, Mgr Booster Program, Cape Canaveral
Larry Mulloy, NASA KSC
George Hardy, NASA MSFC
What is the situation that Boisjoly faces now? He has presented his case. NASA has acted in a way that was unprecedented in Boisjoly's experience. They have put the burden of proof on those who believed it was risky to fly rather than on those who felt it was safe to fly. Fearing that NASA will not continue to make Morton Thiokol the sole contractor for the Solid Rocket Booster program if they insist on holding back the Challenger flight, management has reversed the decision made by engineering. Boisjoly doesn't have the hard data that he has been requesting since last summer and which is now needed to prove that low temperature is a major contributor in hot gas blow-by, and his job appears to be at stake. He has had over a year to work on the joint problem and in that time ten shuttle missions have flown successfully. Is there anything else that can be done at this point?
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