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APPENDIX C - CREW ESCAPE SYSTEMS REPORT

I. INTRODUCTION

The objectives of the First Stage Abort Options Group were to review and report on the various first stage Space Shuttle ascent abort options that were considered for incorporation into the Space Shuttle design during the development phase. The scope of the historical task was to begin at the request for proposal (RFP) time period and trace the evolution of these various options from that time forward to today's current Space Shuttle configuration and operational envelope. The data base for this historical review consisted of minutes of the Space Shuttle Program Requirements Control Board (PRCB), minutes of the Space Shuttle Crew Safety Panel and its follow-on activity, the Space Shuttle Safety Subpanel, annual reports of the Aerospace Safety Advisory Panel, minutes of the Space Shuttle Systems Integration Review, minutes of the Orbiter Avionics Software Control Board, and official memoranda containing significant decisions.

In reporting on the results of this task, it was determined that it would be best to separate the purely historical decision processes from the technical discussions. Although this Task Group's assignment was first stage aborts, it is important to note that many first stage failures are non-time critical, and action to resolve them can wait until the second stage after solid rocket booster (SRB) burnout. To present the complete story, it is also important to address this class of aborts as well. Thus, the first section of this appendix contains the "pure" historical evolution of the Space Shuttle first stage abort options, the second section contains a discussion on the survival paths for first stage failures that are not time critical, and the remaining sections contain technical discussions of the various options considered by the Space Shuttle Program for first stage time critical emergency situations.

The final result of this review supports the Space Shuttle Program's philosophy that, with the configuration that existed at the time of the RFP, the best approach to maximizing the recovery of the Orbiter and minimizing the risk to the crew was to ensure first stage ascent through the process of conservative design, analysis, and certification. The identified failures for first stage ascent were of such a nature that there were no known measurement parameters that would forecast, with sufficient action time, a pending catastrophic event requiring abort. Usually, the event itself was the only indication of the failure, such as attach structure failure or SRB burnthrough. In addition, there were no practical means available that would give complete abort coverage during first stage ascent with any significant increase to crew survivability. Therefore, the program adopted the position that first stage ascent must be assured.

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