Prediction of Planetary Mission Task Performance for Long-Duration Spaceflight

Introduction This study aimed to determine values and ranges for key aerobic fitness variables that can individually map the level of success for planetary mission tasks performance for long-duration spaceflight, with the goal to develop a predictor-testing model that can be performed with in-flight equipment. Methods We studied a group of 45 men and women who completed a series of mission-critical tasks: a surface traverse task and a hill climb task. Participants performed each mission task at a low and moderate intensity designed to elicit specific metabolic responses similar to what is expected for ambulation in lunar and Martian gravities, respectively. Aerobic fitness was characterized via cycling and rowing VO2peak, ventilatory threshold (VT), and critical power. Logistic regression and receiver operating characteristic curve analysis were used to determine the cutoff thresholds for each aerobic fitness parameter that accurately predicted task performance. Results The participants of this study were characterized by a range of cycling VO2peak from 15.5 to 54.1 mL center dot kg(-1)center dot min(-1). A VO2peak optimal cutoff values of X and Y mL center dot kg(-1)center dot min(-1) were identified for the low- and moderate-intensity surface traverse tasks, respectively. For the low- and moderate-intensity hill climb test, the optimal VO2peak cutoff values were X and Y mL center dot kg(-1)center dot min(-1), respectively. VT and critical power also showed high sensitivity and specificity for identifying individuals who could not complete the mission tasks. Conclusion In summary, we identified aerobic fitness thresholds below which task performance was impaired for both low- and moderate-intensity mission-critical tasks. In particular, cycling VO2peak, VT, and rowing CP could each be used to predict task failure.