NASA Accident Investigation Team Working Scenario

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• Working Scenario – Part 1 Sections 1 – 4
• Working Scenario – Part 2 Section 5
• Working Scenario – Part 3 Sections 6 – 12

PREFACE

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.

1.0 INTRODUCTION

1.1 SCOPE

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.