STRATEGIES FOR THE PREFLIGHT CIRCADIAN SHIFTING OF SPACE-SHUTTLE CREWS

In June, 1990, a workshop was put together at NASA/Johnson Space Cente r to address difficulties the astronauts were having in adjusting thei r wake and sleep schedule, both immediately before and during Space Sh uttle missions. The workshop members, prominent investigators in human circadian research, developed a number of strategies by which astrona uts could tackle the problem of circadian adaptation within the demand ing timetable of a Space Shuttle mission. The strategies included both abrupt and gradual methods, and some approaches used artificial ''ver y bright lights'' to reset the physiologic circadian pacemaker. The st rategies have since been operationally implemented on Space Shuttle fl ights, with good success. This is a report of the problems addressed b y the workshop and its recommendations.