Cognitive Performance of Astronauts during Two Space Shuttle Missions

INTRODUCTION The National Aeronautics and Space Administration (NASA) conducted a series of space shuttle missions to investigate the effects of microgravity on human performance. This paper presents the results of a combined analysis of data collected from two space shuttle missions. Astronaut cognitive performance data were collected from three flightcrew astronauts aboard STS-65, the Second International Microgravity Laboratory (IML-2) and from four payload-crew astronauts aboard STS-78, the Life and Microgravity Spacelab (LMS). A computer-based task battery, the Performance Assessment Workstation (PAWS), was used to measure cognitive performance. PAWS contains six performance tasks and two subjective scales (Schlegel, Gilliland, and Shehab, 1993). For the curent analysis, three PAWS tasks were examined. Tbe Critical Tracking (TRK) task requires subjects to manipulate a trackball to maintain an unstable cursor in the center of a horizontal target. An instability parameter (lambda) represents tbe level of difficulty attained. The Dual (DUL) task combines tracking with Stemberg memory search. Root mean square error (RMSE) is a tracking measure of cursor deviation from target. The Directed Attention task simultaneously presents a spatial manikin (MAN) task and a mathematical processing (MTH) task. A cursor directs subjects to perform one of the two subtasks. Throughput integrates reaction time and accuracy into a single performance metric.