AUDITORY ALARM DESIGN FOR NASA CEV APPLICATIONS

This monograph reviews current knowledge in the design of auditory caution and warning signals, and sets criteria for development of 'best practices' for designing new signals for NASA's Crew Exploration Vehicle (CEV) and other future spacecraft, as well as for extra-vehicular operations. A design approach is presented that is based upon cross-disciplinary examination of psychoacoustic research, human factors experience, aerospace practices, and acoustical engineering requirements. Existing alarms currently in use with the NASA Space Shuttle flight deck are analyzed and then alternative designs are proposed that are compliant with ISO 7731, "Danger signals for work places - Auditory Danger Signals", and that correspond to suggested methods in the literature to insure discrimination and audibility. Future development of auditory "sonification" techniques into the design of alarms will allow auditory signals to be extremely subtle, yet extremely useful for indicating trends or root causes of failures. A summary of 'best practice' engineering guidelines is given, followed by results of an experiment involving subjective classification of alarms by ten subjects.