introduction (Раздаточные материалы), страница 4

As astraightforward record of the event, it contains no findings orrecommendations. Designated STS-107, this was the SpaceShuttle Programʼs 113th flight and Columbiaʼs 28th. Theflight was close to trouble-free. Unfortunately, there were noindications to either the crew onboard Columbia or to engineers in Mission Control that the mission was in trouble asa result of a foam strike during ascent. Mission managementfailed to detect weak signals that the Orbiter was in troubleand take corrective action.Columbia was the first space-rated Orbiter. It made the SpaceShuttle Programʼs first four orbital test flights.

Because it wasthe first of its kind, Columbia differed slightly from OrbitersChallenger, Discovery, Atlantis, and Endeavour. Built to anearlier engineering standard, Columbia was slightly heavier,and, although it could reach the high-inclination orbit of theInternational Space Station, its payload was insufficient tomake Columbia cost-effective for Space Station missions.Therefore, Columbia was not equipped with a Space Stationdocking system, which freed up space in the payload bay forlonger cargos, such as the science modules Spacelab andSPACEHAB. Consequently, Columbia generally flew science missions and serviced the Hubble Space Telescope.STS-107 was an intense science mission that required theseven-member crew to form two teams, enabling roundthe-clock shifts.

Because the extensive science cargo andits extra power sources required additional checkout time,the launch sequence and countdown were about 24 hourslonger than normal. Nevertheless, the countdown proceededas planned, and Columbia was launched from Launch Complex 39-A on January 16, 2003, at 10:39 a.m. Eastern Standard Time (EST).At 81.7 seconds after launch, when the Shuttle was at about65,820 feet and traveling at Mach 2.46 (1,650 mph), a largepiece of hand-crafted insulating foam came off an areawhere the Orbiter attaches to the External Tank.

At 81.9seconds, it struck the leading edge of Columbiaʼs left wing.This event was not detected by the crew on board or seenby ground support teams until the next day, during detailedreviews of all launch camera photography and videos. Thisfoam strike had no apparent effect on the daily conduct ofthe 16-day mission, which met all its objectives.The de-orbit burn to slow Columbia down for re-entryinto Earthʼs atmosphere was normal, and the flight profilethroughout re-entry was standard. Time during re-entry isAugust 200311COLUMBIAACCIDENT INVESTIGATION BOARDmeasured in seconds from “Entry Interface,” an arbitrarilydetermined altitude of 400,000 feet where the Orbiter begins to experience the effects of Earthʼs atmosphere. EntryInterface for STS-107 occurred at 8:44:09 a.m.

on February1. Unknown to the crew or ground personnel, because thedata is recorded and stored in the Orbiter instead of beingtransmitted to Mission Control at Johnson Space Center, thefirst abnormal indication occurred 270 seconds after EntryInterface. Chapter 2 reconstructs in detail the events leading to the loss of Columbia and her crew, and refers to moredetails in the appendices.In Chapter 3, the Board analyzes all the information available to conclude that the direct, physical action that initiatedthe chain of events leading to the loss of Columbia and hercrew was the foam strike during ascent.

This chapter reviews five analytical paths – aerodynamic, thermodynamic,sensor data timeline, debris reconstruction, and imagingevidence – to show that all five independently arrive at thesame conclusion. The subsequent impact testing conductedby the Board is also discussed.That conclusion is that Columbia re-entered Earthʼs atmosphere with a pre-existing breach in the leading edge of itsleft wing in the vicinity of Reinforced Carbon-Carbon (RCC)panel 8. This breach, caused by the foam strike on ascent,was of sufficient size to allow superheated air (probably exceeding 5,000 degrees Fahrenheit) to penetrate the cavity behind the RCC panel. The breach widened, destroying the insulation protecting the wingʼs leading edge support structure,and the superheated air eventually melted the thin aluminumwing spar.

Once in the interior, the superheated air began todestroy the left wing. This destructive process was carefullyreconstructed from the recordings of hundreds of sensors inside the wing, and from analyses of the reactions of the flightcontrol systems to the changes in aerodynamic forces.By the time Columbia passed over the coast of Californiain the pre-dawn hours of February 1, at Entry Interface plus555 seconds, amateur videos show that pieces of the Orbiterwere shedding. The Orbiter was captured on videotape during most of its quick transit over the Western United States.The Board correlated the events seen in these videos tosensor readings recorded during re-entry. Analysis indicates that the Orbiter continued to fly its pre-planned flightprofile, although, still unknown to anyone on the ground oraboard Columbia, her control systems were working furiously to maintain that flight profile.

Finally, over Texas, justsouthwest of Dallas-Fort Worth, the increasing aerodynamicforces the Orbiter experienced in the denser levels of the atmosphere overcame the catastrophically damaged left wing,causing the Orbiter to fall out of control at speeds in excessof 10,000 mph.The chapter details the recovery of about 38 percent of theOrbiter (some 84,000 pieces) and the reconstruction andanalysis of this debris. It presents findings and recommendations to make future Space Shuttle operations safer.Chapter 4 describes the investigation into other possiblephysical factors that may have contributed to the accident.The chapter opens with the methodology of the fault tree12Report Volume Ianalysis, which is an engineering tool for identifying everyconceivable fault, then determining whether that fault couldhave caused the system in question to fail.

In all, more than3,000 individual elements in the Columbia accident faulttree were examined.In addition, the Board analyzed the more plausible fault scenarios, including the impact of space weather, collisions withmicrometeoroids or “space junk,” willful damage, flight crewperformance, and failure of some critical Shuttle hardware.The Board concludes in Chapter 4 that despite certain faulttree exceptions left “open” because they cannot be conclusively disproved, none of these factors caused or contributedto the accident. This chapter also contains findings and recommendations to make Space Shuttle operations safer.PART TWO: WHY THE ACCIDENT OCCURREDPart Two, “Why the Accident Occurred,” examines NASAʼsorganizational, historical, and cultural factors, as well ashow these factors contributed to the accident.As in Part One, Part Two begins with history.

Chapter 5examines the post-Challenger history of NASA and itsHuman Space Flight Program. A summary of the relevantportions of the Challenger investigation recommendationsis presented, followed by a review of NASA budgets to indicate how committed the nation is to supporting human spaceflight, and within the NASA budget we look at how theSpace Shuttle Program has fared. Next, organizational andmanagement history, such as shifting management systemsand locations, are reviewed.Chapter 6 documents management performance related toColumbia to establish events analyzed in later chapters. Thechapter begins with a review of the history of foam strikes onthe Orbiter to determine how Space Shuttle Program managersrationalized the danger from repeated strikes on the Orbiterʼs Thermal Protection System.

Next is an explanationof the intense pressure the program was under to stay onschedule, driven largely by the self-imposed requirement tocomplete the International Space Station. Chapter 6 then relates in detail the effort by some NASA engineers to obtainadditional imagery of Columbia to determine if the foamstrike had damaged the Orbiter, and how management dealtwith that effort.In Chapter 7, the Board presents its view that NASAʼs organizational culture had as much to do with this accidentas foam did. By examining safety history, organizationaltheory, best business practices, and current safety failures,the report notes that only significant structural changes toNASAʼs organizational culture will enable it to succeed.This chapter measures the Shuttle Programʼs practicesagainst this organizational context and finds them wanting.The Board concludes that NASAʼs current organizationdoes not provide effective checks and balances, does nothave an independant safety program, and has not demonstrated the characteristics of a learning organization.Chapter 7 provides recommendations for adjustments inorganizational culture.August 2003COLUMBIAACCIDENT INVESTIGATION BOARDChapter 8, the final chapter in Part Two, draws from theprevious chapters on history, budgets, culture, organization,and safety practices, and analyzes how all these factors contributed to this accident.

The chapter opens with “echoes ofChallenger” that compares the two accidents. This chaptercaptures the Boardʼs views of the need to adjust management to enhance safety margins in Shuttle operations, andreaffirms the Boardʼs position that without these changes,we have no confidence that other “corrective actions” willimprove the safety of Shuttle operations. The changes werecommend will be difficult to accomplish – and will beinternally resisted.PART THREE: A LOOK AHEADPart Three summarizes the Boardʼs conclusions on whatneeds to be done to resume our journey into space, listssignificant observations the Board made that are unrelatedto the accident but should be recorded, and provides a summary of the Boardʼs recommendations.In Chapter 9, the Board first reviews its short-term recommendations. These return-to-flight recommendations are theminimum that must be done to essentially fix the problemsthat were identified by this accident.