Challenger Accident or what you think you know can still hurt you CAPT RT Soule Supervisor of Shipbuilding Newport News “engineers and managers together developed a definition of the situation that allowed them to carry on as if nothing was wrong when they continually faced evidence that something was wrong.” -Much of what you think you know about Challenger is wrong since it is strongly influenced by hindsight --The big challenge in accident investigations is overcoming “How could they have been so careless/stupid” type thinking, which seriously degrades our ability to learn useful information

Outline NASA Shuttle Organization What We Think We Know Why Most Accident Investigations Get “it” Wrong Flight Readiness Reviews Brief History of Solid Rocket Boosters (SRBs) One Explanation: Normalization of Deviance SRB Specific Case Eve of the Launch Conclusions Premise of the book is that individual behavior cannot be understood without considering its organizational and environmental context.

References Report of the Presidential Commission on the Space Shuttle Challenger Accident The Challenger Launch Decision: Risky Technology, Culture, and Deviance at NASA, Diane Vaughan Just Culture, Sidney Dekker Tenerife Air Disaster, Karl Weick

NASA Shuttle Organization Johnson Space Center, Houston TX –Orbiter management Marshall Space Flight Center, Huntsville AL –Propulsion system (Main Eng, External Tnk, SRBs) Kennedy Space Center, Cape Canaveral FL –Assembling components, launch Morton Thiokol Wasatch, Brigham City UT –SRB Prime Contractor

What We Think We Know NASA compromised safety for cost and schedule NASA pressured Morton Thiokol to launch NASA ignored the O-ring risk Accident cause was O-ring failure complicated by bad weather

Getting it Wrong

To understand failure Don’t ask –Where did they mess up? –Why didn’t they notice what we find important now? The real question is –Why did it make sense for them to do what they did? Otherwise, if they knew what you know after the fact, they would not have done what they did.

Getting it Wrong (cont’d) We want to find a cause “If there is no...cause, then the world is a more disordered and dangerous place Accident reports, and much of the history we write, struggle to hold that nightmare at bay” (Galison,2000,p.32)

Flight Readiness Review Mission Management Team Flight Readiness Review (FRR) Pre-Flight Readiness Review Marshall Space Flight Center FRR Main Engine Contractor Solid Rocket Booster Cr External Tank Contractor Kennedy Space Center Launch Readiness Review Shuttle Processing Contractor Johnson Space Center Orbiter Contractor System Integration Contractor Level 1 Level 2 Level 3 Level 4

Risk Management Risk cannot be eliminated, must be managed NASA Acceptable Risk Process –Formal, technical, layered review Flight Readiness Review –Show shuttle ready to fly and fly safely –Delta Review Concept

History of the SRBs Designed by MT, based on Titan III Differed fm Titan III –Segment sealing method –Higher combustion pressure –Reusable

Joint Rotation Tendency to bend open Joint deviated from industry std More tests necessary to show risk acceptable

History of the SRBs SRB Assembly

Normalization of Deviance Production of Culture Culture of Production Limited Knowledge

Production of Culture Work Group Culture How Culture Is Produced –Language used –Types of meetings, formal rules –Tests and analyses –Schedule procedures –Complex problems

Culture of Production Production mentality -> get the job done Need to maintain shuttle launch schedule Pressure not to delay launch

Limited Knowledge Built-in impediments to knowledge flow –patterns of information –organizational structure, processes Impact –mixed, weak, routine signals –unequal information

SRB Specific Case of Normalization of Deviance Re-defined deviation as acceptable –Danger signals –Official recognition of increased risk –Evidence review –Risk acceptance (not joint redesign) –Launch

Eve of the Launch – 26 Jan Launch date slipped from 22 Jan to 26 Jan Launch postponed to 27 Jan – bad wx Launch postponed to 28 Jan – mech probs Jan –NASA asked MT to review effect of cold on SRM performance 1530 EST MT O-ring task forces meets in UT

Eve of the Launch – 27 Jan , Telcon 1 –MT Engineers recommend delaying launch , Telcon 2 –MT tried to prove launch risk not acceptable < 53 F –NASA challenged –MT management decision –MT recommends launch

Eve of the Launch – 28 Jan 0130 – Temp 29 F –Ice inspection –Rockwell asked about impact of ice on Orbiter 0700, 0830 – Two more ice inspections 0900 – Final NASA – Contractor mtg to assess readiness – Final ice inspection, Temp 36F

Teleconference Participants Morton Thiokol Marshall Space Flight Center Kennedy Space Center

Eve of the Launch , Telcon 1 –MT Engineers recommend delaying launch –Thiokol too no official position –Connection bad, not all people could hear –45 min, unstructured data discussion There were no documents to lead or follow the discussion –Agreed to a follow up telcon using FRR format –Key Question: If primary O-ring did not seal, would sec O-ring seal before resiliency became more significant?

Eve of the Launch Between Conferences –Not everyone in the East was available –Thiokol engineers working on Rec’s/Concl’s did not have access to all charts , Telcon 2 –MT tried to prove launch risk not acceptable < 53 F –NASA managers felt correlation of joint failure with temperature was not proven by Thiokol –MT management risk decision –MT recommends launch

Eve of the Launch (just included to capture extra notes) Between Conferences –Not everyone in the East was available –Thiokol engineers working on Rec’s/Concl’s did not have access to all charts , Telcon 2 –MT tried to prove launch risk not acceptable < 53 F –NASA managers felt correlation of joint failure with temperature was not proven by Thiokol –MT management risk decision –MT recommends launch

Post Accident Temperature Analysis Calculated Joint Temperature, Degrees F Number of Incidents STS-51-C 41D 61A STS-2 41C 61C 41B

Post Accident Temperature Analysis Calculated Joint Temperature, Degrees F Number of Incidents STS-51-C 41D 61A STS-2 41C 61C 41B Flts with no incidents

Eve of the Launch – 28 Jan

1125 – Terminal countdown 1138 – STS 51 – L launched, Temp 36 F T + 73 sec – Fireball erupted

Summary On Navy ships, shipyards, Rx Depts, there is always pressure to produce Even processes designed to make us safer can lead us astray (if we don’t use them well) Failure does not strike like bolt from the blue …(there are signs, but you must know where to look) There are no simple fixes …(but there are things that can make us safer)

Summary Signs that failure may be near: –You are in a hurry (behind schedule or near the end of shift) –You want something very badly (or expect something) –You rushed through the brief (or did not do one) –You don’t know what to expect after you act –You are preoccupied –No one disagrees with you (or asks any questions at a brief) –You are doing something for the first time/infrequently –Something does not “feel” right

Summary Things that can make us safer: –Welcome disagreement –Speak up when you have a question or don’t understand, you may be the only one who sees “the problem” –Spend more time thinking about what could go wrong, how you would know, and what you could do about it –Learn to trust your sense that it’s not right

For Further Study storage-area/carl-vinson/ storage-area/carl-vinson/ htmhttp://ethics.tamu.edu/ethics/shuttle/shuttle 1.htm essays/thiokolshuttle/shuttle_post.aspxhttp://onlineethics.org/CMS/profpractice/pp essays/thiokolshuttle/shuttle_post.aspx empindex/RB-intro/Erosion.aspxhttp://onlineethics.org/CMS/profpractice/ex empindex/RB-intro/Erosion.aspx

Further Reading Challenger Launch Decision, Vaughan Dekker: Ten Questions, Just Culture Managing the Unexpected, Weick, Sutcliff

Backup Slides

Mission STS-2 Nov 81 STS-41B Feb 84 STS-41D Aug 84 STS-51C Jan 85 STS-51B Apr 85 Danger Signal Erosion of Primary 1° erosion, 2 joints 1° Blow by Blow by reached 2° 2° eroded, 1° failed Recogniti on Only MT and Mrshll Engrs Started tracking officially Reviewed at all levels of FRR Major review Feb 85, all FRR Launch Constraint Imposed Review CalcsSelf-limitingBlow by small, self limiting Low temps before launch 1 ° out of position, tests, calcs Acceptan ce Altered installation process Erosion acceptable, redund not impacted Performed as predicted Low temps rare, blow by within experience base Altered installation process to seal O- rings better Launch STS-3 Nov 82 STS-41C Apr 84 STS-41GSTS-51ESTS-51F