Astronauts eye-head coordination dysfunction over the course of twenty space shuttle flights.

This article investigates how weightlessness during space flight affects astronauts' eye-head coordination (EHC) in acquiring visual targets at varying angular eccentricities. Studying 34 NASA astronauts across 20 Space Shuttle missions from flight day 1 to 15, the research found that transitions from Earth gravity (1 g) to microgravity (0 g) significantly altered the timing, velocity, amplitude, and coordination of eye and head movements, with initial decreases in gaze performance followed by gradual adaptation over two weeks. These changes are attributed to shifts in spatial orientation reference frames, reduced head movement to mitigate space motion sickness, altered vestibulo-ocular reflex function, and biomechanical and neurophysiological adaptations in microgravity. The findings have implications for astronaut spatial orientation and control during missions involving variable gravity environments, such as future Moon and Mars exploration.