The purpose of this study is to validate the acceptability, operational feasibility and efficacy of a combined fatigue countermeasure comprised of shorter-wavelength light and exercise during operational Orbit 1 night shifts to improve alertness and performance of flight mission controllers.

Specifically, the investigators will:

1. Feasibility. Test the feasibility of developing a break room containing fatigue countermeasures (shorter-wavelength light and exercise equipment) to be used by flight mission controllers during Orbit 1 night shifts, and the feasibility to schedule regular breaks during the Orbit 1 shift so that flight mission controllers have the opportunity to use the fatigue countermeasures break room.
2. Acceptability. Test the acceptability of the use of the fatigue countermeasures break room evaluating when and how the room is used by flight mission controllers, as measured on End-of-Shift Productivity Questionnaire.
3. Test the hypothesis that alertness and performance will be impaired in flight mission controllers during Orbit 1 operational night shifts as compared to flight mission controllers working a non-console day shift.
4. Test the hypothesis that alertness and performance of flight mission controllers who exercise and are exposed to shorter wavelength light during the Orbit 1 night shift will be significantly more alert and have better mood, performance (e.g., less Psychomotor Vigilance Task (PVT) lapses, increased productivity) than those same mission controllers working Orbit 1 night shifts without exposure to the shorter wavelength light and exercise.
5. Test the acceptability, operational feasibility and efficacy of implementing an anonymous sleep disorders screening for flight controllers, evaluated by number of visitors to the screening web site and the number of completed assessments.

Each participant will have three data collection periods. Each data collection period will last one shift rotation (5 -7 days): One 5-shift or 7-shift block of Orbit 1 night shifts on console with access to photic and exercise countermeasures, a second 5-shift or 7-shift block of Orbit 1 night shifts on console with no access to countermeasures, and a third 5-shift block of daytime office work off console. We will be measuring sleep via a wrist worn activity measuring device and compliance of exercise intervention via a small, commercially available heart monitor worn around the chest underneath clothing. The activity device will be worn continuously and the heart monitor will be worn on shift. These devices will be downloaded at the end of each block of shifts. Subjects will complete a short baseline questionnaire once at the beginning of the study. Subjective alertness will be assessed with the Karolinska Sleepiness Scale (KSS), performance testing will occur regularly and 'end of shift' questionnaires will be completed at the end of each shift. Drowsiness will be measured on the commute to and from work with the Optalert.

Inclusion Criteria:

• Must be current Johnson Space Center International Space Station Flight Controller or Flight Director cleared to sit console for Orbit 1 work shift
• Work schedule must meet both study needs and National Aeronautics and Space Administration (NASA) scheduling operational constraints

Exclusion Criteria:

• none