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 V[Combining Dot Above]O2peak, ventilatory threshold (VT), and critical power. Logistic regression and receiver operating characteristic (ROC) 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 V[Combining Dot Above]O2peaks from 15.5 to 54.1 ml kg min. A V[Combining Dot Above]O2peak optimal cutoff values of X and Y ml kg min were identified for the low and moderate intensity surface traverse task respectively. For the low and moderate intensity hill climb test the optimal V[Combining Dot Above]O2peak cutoff values were X and Y ml kg min, 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. Specifically, cycling V[Combining Dot Above]O2peak, VT, and rowing CP could each be used to predict task failure.