Nasa tragedies and lessons


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Nasa tragedies and lessons

  1. 1. NASA’S 3 Tragedies Reflections and Lessons
  2. 2. Apollo 1 Fire• January 27, 1967, the crew of Apollo 1, climbed into the crew module for a plugs- out test, which was not expected to be hazardous.• The module was pressurized to 16 psia, higher than ambient, and was 100% oxygen, which the contractor recommended against.
  3. 3. Apollo 1 Fire cont.• The crew module had a number of known but uncorrected flaws and the crew had expressed concern about fire hazards.• The astronauts had also lobbied successfully for an outward opening door, but that design change was not incorporated here.• Still, flawed or not, the hope was to successfully pass the test today and launch it three weeks later in February.
  4. 4. Apollo 1 Fire cont.• At 6:31:07, *before the test had even started*, the first cry of fire came from the cabin.• For about 10 seconds, one could hear frantic movements followed by Chafee yelling, “We’ve got a bad fire! Let’s get out! We’re burning up! We’re on fire! Get us out of here!” Then, a scream of pain and the end of the transmission, seventeen seconds after the first report of fire.• The crew module ruptured from the pressure and toxic black smoke poured from the module.
  5. 5. Apollo 1 Fire cont.• It took another eight minutes before they could open the hatch, by which time the fire had gone out. It took 7.5 hours to remove the crews remains, as they were fused in place by the melted nylon of their suits. It was not a fun way to die.• In the end, a number of key factors were called out as potential causes and contributors. The high pressure oxygen environment was very dangerous from a flammability standpoint (”in which a bar of aluminum can burn like wood”).
  6. 6. Apollo 1 Fire cont.• There was a wealth of off-gassing flammable nonmetallics like nylon and velcro. Wiring and plumbing was substandard (note that 1407 wiring *design* problems were corrected after Apollo 1) with a stripped and abraded wire near a leaky coolant line (a potential exothermic explosion) but just the static electricity from their suits were found sufficient to have started a fire in that atmosphere. We were not short of smoking guns and no single cause was ever determined as *the* cause.
  7. 7. Apollo 1 Fire cont.• We were reckless, we were sloppy, and we thought that the success with Mercury and Gemini at 100% oxygen made us bulletproof. Astronauts Edward H. White II, Virgil I. Grissom, and Roger B. Chaffee paid the price.
  8. 8. Apollo 1 Fire cont.• Nonmetallics are given careful consideration before flight, requiring both toxicity and flammability off-gassing tests (if not a previously flown material).• Even the simplest ground tests are done with emergency personnel on site, with procedures for rescuing test subjects practiced and in hand, a thorough safety review before proceeding.• We fly with an air mixture (except in the suits) and wiring and materials are held to very high standards. Materials used, particular “on” the crewmembers must be self-extinguishing.
  9. 9. Challenger Accident January 28, 1986
  10. 10. Challenger• The first time it blew up, it was such a shock, because most people thought it would never ever happen. But once you get the idea that spacecraft sometimes have catastrophic events, then it becomes less of a shock.
  11. 11. • January 28, 1986, the shuttle Challenger explodes 73 seconds into its launch, killing all seven crew members• Investigation reveals that a solid rocket booster (SRB) joint failed, allowing flames to impinge on the external fuel tank
  12. 12. Challenger…• Liquid hydrogen tank explodes, ruptures liquid oxygen tank• Resulting massive explosion destroys the shuttle
  13. 13. The Legacy of Challenger• The Rogers Commission, which investigated the incident, determined: – The SRB joint failed when jet flames burned through both o-rings in the joint – NASA had long known about recurrent damage to o-rings – Increasing levels of o-ring damage had been tolerated over time • Based upon the rationale that “nothing bad has happened yet”
  14. 14. The Legacy… continued• The Commission also determined that: – SRB experts had expressed concerns about the safety of the Challenger launch – NASA’s culture prevented these concerns from reaching top decision-makers – Past successes had created an environment of over-confidence within NASA – Extreme pressures to maintain launch schedules may have prompted flawed decision-making• The Commission’s recommendations addressed an number of organizational, communications, and safety oversight issues
  15. 15. Columbia FEB 1, 2003 8:59 EST Space shuttle Columbia, re-entering Earth’s atmosphere at 10,000 mph, disintegrates– All 7 astronauts are killed– $4 billion spacecraft is destroyed– Debris scattered over 2000 sq-miles of Texas– NASA grounds shuttle fleet for 2-1/2 years
  16. 16. Columbia- The Physical Cause• Insulating foam separates from external tank 81 seconds after lift-off• Foam strikes underside of left wing, breaches thermal protection system (TPS) tiles• Superheated air enters wing during re-entry, melting aluminum struts• Aerodynamic stresses destroy weakened wing
  17. 17. A Flawed Decision Process• Foam strike detected in launch videos on Day 2• Engineers requested inspection by crew or remote photo imagery to check for damage• Mission managers discounted foam strike significance• No actions were taken to confirm shuttle integrity or prepare contingency plans
  18. 18. Columbia- The Organizational Causes• NASA had received painful lessons about its culture from the Challenger incident• CAIB found disturbing parallels remaining at the time of the Columbia incident… these are the topic of this presentation“In our view, the NASAorganizational culture had asmuch to do with this accident asthe foam.” CAIB Report, Vol. 1, p. 97
  19. 19. Columbia Key Issues• With little corroboration, management had become convinced that a foam strike was not, and could not be, a concern.• Why were serious concerns about the integrity of the shuttle, raised by experts within one day after the launch, not acted upon in the two weeks prior to return?• Why had NASA not learned from the lessons of Challenger?
  20. 20. Key Organizational Culture Findings – What NASA Did Not Do1. Maintain Sense Of Vulnerability2. Combat Normalization Of Deviance3. Establish an Imperative for Safety4. Perform Valid/Timely Hazard/Risk Assessments5. Ensure Open and Frank Communications6. Learn and Advance the Culture
  21. 21. Maintaining a Sense of Vulnerability“Let me assure you that, as ofyesterday afternoon, the Shuttlewas in excellent shape, … therewere no major debris systemproblems identified….” NASA official on Day 8“The Shuttle has become amature and reliable system …about as safe as today’stechnology will provide.” NASA official in 1995
  22. 22. Maintaining a Sense of Vulnerability• NASA’s successes (Apollo program, et al) had created a “can do” attitude that minimized the consideration of failure• Near-misses were regarded as successes of a robust system rather than near-failures – No disasters had resulted from prior foam strikes, so strikes were no longer a safety-of-flight issue – Challenger parallel… failure of the primary o-ring demonstrated the adequacy of the secondary o-ring to seal the joint
  23. 23. Combating Normalization of Deviance• After 113 shuttle missions, foam shedding, debris impacts, and TPS tile damage came to be regarded as only a routine maintenance concern “…No debris shall emanate from the critical zone of the External Tank on the launch pad or during ascent…” Ground System Specification Book – Shuttle Design Requirements
  24. 24. Combating Normalization of Deviance• Each successful mission reinforced the perception that foam shedding was unavoidable…either unlikely to jeopardize safety or an acceptable risk Foam shedding, which violated the shuttle design basis, had been normalized Challenger parallel… tolerance of damage to the primary o-ring… led to tolerance of failure of the primary o-ring… which led to the tolerance of damage to the secondary o- ring… which led to disaster
  25. 25. Establish An Imperative for Safety • The shuttle safety organization, funded by the programs it was to oversee, was not positioned to provide independent safety analysis • The technical staff for both Challenger and Columbia were put in the position of having to prove that management’s intentions were unsafe “When I ask for the budget to be – This reversed their normal role of having to cut, prove I’m told it’s going to impact safety on mission safety the Space Shuttle … I think that’s a bunch of crap.”
  26. 26. Establish An Imperative for Safety As with Challenger, future NASA funding required meeting an ambitious launch schedule – Conditions/checks, once “critical,” were now waived –A significant foam strike on Desktop screensaver at a recent mission was not NASA resolved prior to Columbia’s launch International Space –Priorities conflicted… and Station production won over safety deadline 19 Feb 04
  27. 27. Perform Valid/Timely Hazard/Risk Assessments • NASA lacked consistent, structured approaches for identifying hazards and assessing risks • Many analyses were subjective, and many action items from studies were not addressed • more activity today risk tile damage or are people“AnyIn lieu of properon the assessments, manyjustrelegated to crossing their fingers and hoping for the best?” identified concerns were simply labeled Email Exchange at NASA as “acceptable”“… hazard analysis processes are applied inconsistently across • Invalid computer modeling of thesystems, subsystems, assemblies, and components.” foam CAIB Report, Vol. 1, p. 188
  28. 28. Ensure Open and Frank Communications• Management adopted a uniform mindset that foam strikes were not a concern and was not open to contrary opinions.• The organizational culture – Did not encourage “bad news” – Encouraged 100% consensus – Emphasized only “chain of command” communications – Allowed rank and status to trump expertise I must emphasize (again) that severe enough damage… could present potentially grave hazards… Remember the NASA safety posters everywhere around stating, “If it’s not safe, say so”? Yes, it’s that serious.  Memo that was composed but never sent
  29. 29. Ensure Open and Frank Communications• Lateral communications between some NASA sites were also dysfunctional – Technical experts conducted considerable analysis of the situation, sharing opinions within their own groups, but this information was not shared between organizations within NASA – As similar point was addressed by the Rogers Commission on the Challenger
  30. 30. Learn and Advance the Culture• CAIB determined that NASA had not learned from the lessons of Challenger• Communications problems still existed – Experts with divergent opinions still had difficulty getting heard• Normalization of deviance was still occurring• Schedules often still dominated over safety concerns• Hazard/risk assessments were still
  31. 31. … An Epilog• Shuttle Discovery was launched on 7/26/05• NASA had formed an independent Return To Flight (RTF) panel to monitor its preparations• 7 of the 26 RTF panel members issued a minority report prior to the launch
  32. 32. … An Epilog• During launch, a large piece of foam separated from the external fuel tank, but fortunately did not strike the shuttle, which landed safely 14 days later• The shuttle fleet was once again grounded, pending resolution of the problem with the external fuel tank insulating foam
  33. 33. …NOT Ensuring Open and Frank Communications• The bearer of “bad news” is viewed as “not a team player”• Safety-related questioning “rewarded” by requiring the suggested to prove he / she is correct• Communications get altered, with the message softened, as they move up or down the management chain• Safety-critical information is not moving laterally between work groups
  34. 34. …NOT Learning and Advancing the Culture• Recurrent problems are not investigated, trended, and resolved• Investigations reveal the same causes recurring time and again• Staff expresses concerns that standards of performance are eroding• Concepts, once regarded as organizational values, are now subject to expedient reconsideration
  35. 35. “Engineering By View Graph” • The CAIB faulted shuttle project staff for trying to summarize too much important information on too few PowerPoint slides • We risk the same criticism here • This presentation introduces the concept of organizational“When engineering analyses and risk assessments are effectiveness and safety culture, ascondensed to fit on a standard form or overhead slide,information is inevitably lost… the priority assigned to exemplified bymisrepresented by its placement on a the case studiesinformation can be easilychartpresented and the language that is used.”
  36. 36. May we never forget…