A spaceflight operation complexity measure and its experimental validation

Abstract

A measure of operation complexity in spaceflight is proposed using a weighted Euclidean norm based on four factors: complexity of operation step size (COSS), complexity of operation logic structure (COLS), complexity of operation instrument information (COII), and complexity of space mission information (CSMI). The development of the operation complexity measure followed four steps. First, four factors were identified to be reflected in the operation complexity measure for spaceflight. Second, the entropy theory was adopted to measure the four factors. Then, the weights of the four factors were determined based on a questionnaire survey of 10 astronauts. Finally, the operation complexity values of spaceflight operations were determined by the weighted Euclidean norm of the four factors. To verify the validity of this complexity measure, a one-factor experiment was designed to test the proposed hypotheses. Ten subjects participated in the experiment and performed 179 trials. Both objective indexes (operation time and error rate) and subjective indexes (workload evaluated by NASA Task Load Index questionnaire and subjective complexity rating) were used in the experiment. The data analysis showed that the average operation time, subjective complexity rating, and subjective workload could be predicted well from the operation complexity value ( R = 0.876, 0.802, and 0.698, respectively); and the error rate could only be partly explained by the operation complexity value ( R = 0.343). Relevance to industry The proposed operation complexity measure can be used for ergonomics evaluation of spaceflight operation design. It can also be used for astronaut training planning. Training resources can be allocated to spaceflight tasks according to their operation complexity.