Long-duration space missions often require long work hours and shifting sleep schedules for astronauts and flight controllers, resulting in decreased alertness and performance. Dr. Charles A. Czeisler is leading a project looking at the use of a lighting countermeasure to improve alertness and performance during night-shift work on long-duration missions. The researchers collected data during a 105-day isolation study in Russia, in which crew members worked a night shift every fifth night and controllers worked 24-hour shifts.
The data will be used to determine the feasibility of monitoring sleep and circadian rhythms and to test the effects of sudden sleep schedule shifts. The researchers are testing the hypothesis that shorter wavelength light will be more beneficial to crew members than intermediate and longer wavelength light. Czeisler and colleagues are also testing the hypotheses that the last third of a 24-hour shift is when controller performance is reduced the most and that shorter wavelength light will be a better countermeasure to mitigate performance reduction during a 24-hour shift.
If lighting proves to be an effective countermeasure, it will reduce the need for pharmaceutical interventions, which could have negative side effects that impact mission operations.