Defining Reliability and Robustness from a Human Factors Perspective

A human factors team was tasked with assessing best practices for developing a crewed space vehicle that is both reliable and robust. The team identified two broad dimensions of human factors are relevant to system design. Namely, the attributes of the product, and the processes used to develop the product. The “product” includes hardware, software, documentation, training systems, and procedures throughout all phases of the system life, including construction, testing, operation and maintenance. Three product attributes relevant to robustness are the extent to which task demands are within human capabilities, the capacity of the system to cope with unanticipated human actions, and the ability of the system to make use of unique human capabilities during non-routine situations. The “process” dimension of human factors relates to the activities that start in the early stages of design, and continue throughout the life of the system. There are, of course, no guarantees that a formal consideration of human factors throughout the design process will identify all the relevant human issues. In the absence of such a consideration, however, problems are virtually assured.