A report describes the history and the continuing evolution of an avionic system aboard the space shuttle, denoted the caution and warning system, that generates visual and auditory displays to alert astronauts to malfunctions. The report focuses mainly on planned human-factors-oriented upgrades of an alphanumeric fault-summary display generated by the system. Such upgrades are needed because the display often becomes cluttered with extraneous messages that contribute to the difficulty of diagnosing malfunctions. In the first of two planned upgrades, the fault-summary display will be rebuilt with a more logical task-oriented graphical layout and multiple text fields for malfunction messages. In the second upgrade, information displayed will be changed, such that text fields will indicate only the sources (that is, root causes) of malfunctions; messages that are not operationally useful will no longer appear on the displays. These and other aspects of the upgrades are based on extensive collaboration among astronauts, engineers, and human-factors scientists. The report describes the human-factors principles applied in the upgrades.

This report was written by Jeffrey W. McCandless and Robert S. McCann of Ames Research Center and Bruce R. Hilty of Johnson Space Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Electronics/Computers category.