Posted: Friday, July 11, 2003
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This Working Scenario report was written to document the collection of known facts, events, timelines, and historical information of particular interest to the final flight of Columbia. The report was written with the understanding that it could be published, either in part or in its entirety, as part of the official Columbia Accident Investigation Board (CAIB) report. The report includes information and results from numerous analyses, tests, and simulations related to the Columbia investigation that have been completed, or were ongoing at the time that this report was completed. It is anticipated that additional analytical and test results will emerge from ongoing work, as well as from future activities associated with the Columbia investigation and efforts related to the Return-To-Flight work. This Working Scenario includes information and results as they existed up to and including July 8, 2003.
The Working Scenario is the result of a joint effort between the Columbia Accident Investigation Board (CAIB) and the NASA Accident Investigation Team (NAIT). This effort collates and documents the principal facts related to specific vehicle element events, timelines, and data. It also includes pertinent historical data surrounding some of the key vehicle element considerations in the investigation. The scenario addresses the chronology of vehicle events from prelaunch, Launch Countdown (LCD), launch/ascent, orbit, and entry as well as specific information for the External Tank (ET) and the Left Hand (LH) wing, including aspects of the Reinforced Carbon-Carbon (RCC) and attachment hardware. Vehicle processing and significant preflight events and milestones are also discussed. The scenario addresses technical aspects only, and does not address management practices or philosophies, or other organizational considerations.
The chronological portion of the scenario is contained in Sections 2 through 5 of this report. These sections discuss the prelaunch, launch, orbit, and deorbit/entry portions of the Space Transportation System 107 mission (STS-107). Sections 6 through 8 address the facts related to the Reusable Solid Rocket Motor (RSRM), Solid Rocket Booster (SRB), and Space Shuttle Main Engine (SSME) elements. Section 9 addresses relevant environmental factors such as weather and age of the ET. Section 10 addresses the details of Columbia vehicle processing, specifically as it pertains to the LH wing, from the most recent Orbiter Major Maintenance (OMM) at Palmdale, California, through the processing for STS-107. This section also includes a number of design and historical considerations for the LH wing and for the RCC in general. Section 11 addresses several aspects of the ET, including manufacturing, Kennedy Space Center (KSC) processing, Thermal Protection System (TPS) requirements, and numerous aspects of the foam insulation. These discussions provide the history of the bipod foam ramp design, fabrication, testing, and address the details of bipod foam ramp debris failure modes, testing, and analyses. Section 12 briefly summarizes the discussion of the working scenario.
The data sources and types include, but are not limited to, telemetry from all flight phases, Modular Auxiliary Data System (MADS) data from ascent and entry, video and imagery from launch/ascent and entry, and launch/ascent radar. It also includes reconstructed aerodynamic and vehicle loads, Radar Cross Section (RCS) and ballistics, aero/thermal, structural, debris forensics, post-flight test data (TPS impact, ET/SRB bolt catcher, wind tunnel, etc.), and prelaunch processing.
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