uses a computer in a sleep station in the Zvezda Service Module on the International Space Station. in his sleeping compartment on Mir, called a
Kayutka|alt=A man, dressed in blue work clothing, seen in a small cubicle. During the
Apollo program, it was discovered that adequate sleep in the small volumes available in the
command module and
Lunar Module was most easily achieved if (1) there was minimum disruption to the pre-flight circadian rhythm of the crew members; (2) all crew members in the spacecraft slept at the same time; (3) crew members were able to doff their suits before sleeping; (4) work schedules were organized – and revised as needed – to provide an undisturbed (radio quiet) 6-8 hour rest period during each 24-hour period; (5) in zero-g, loose restraints were provided to keep the crewmen from drifting; (6) on the lunar surface, a hammock or other form of bed was provided; (7) there was an adequate combination of cabin temperature and sleepwear for comfort; (8) the crew could dim instrument lights and either cover their eyes or exclude sunlight from the cabin; and (9) equipment such as pumps were adequately muffled. NASA management currently has limits in place to restrict the number of hours in which astronauts are to complete tasks and events. This is known as the "Fitness for Duty Standards". Space crews' current nominal number of work hours is 6.5 hours per day, and weekly work time should not exceed 48 hours. NASA defines critical workload overload for a space flight crew as 10-hour work days for 3 days per work week, or more than 60 hours per week (NASA STD-3001, Vol. 1). Astronauts have reported that periods of high-intensity workload can result in mental and physical fatigue. Studies from the medical and aviation industries have shown that increased and intense workloads combined with disturbed sleep and fatigue can lead to significant health issues and performance errors. Research suggests that astronauts' quality and quantity of sleep while in space is markedly reduced than while on Earth. The use of sleep-inducing medication could be indicative of poor sleep due to disturbances. Current space flight data shows that accuracy, response time and recall tasks are all affected by sleep loss, work overload, fatigue and circadian desynchronization.
Factors that contribute to sleep loss and fatigue The most common factors that can affect the length and quality of sleep while in space include: • noise • physical discomfort • voids • disturbances caused by other crew members • temperature An evidence gathering effort is currently underway to evaluate the impact of these individual, physiological and environmental factors on sleep and fatigue. The effects of work-rest schedules, environmental conditions and flight rules and requirements on sleep, fatigue and performance are also being evaluated.
Paul J. Weitz said that on
Skylab he could not sleep vertically despite being weightless, so removed the metal frame in his sleeping bag and slept horizontally on it.
Factors that contribute to circadian desynchronization Exposure to light is the largest contributor to circadian desynchronization on board the ISS. Since the ISS orbits the Earth every 1.5 hours, the flight crew experiences 16 sunrises and sunsets per day. Slam shifting (sleep shifting) is also a considerable external factor that causes circadian desynchronization in the current space flight environment. Other factors that may cause circadian desynchronization in space: •
shift work • extended work hours • timeline changes • slam shifting (sleep shifting) • prolonged light of lunar day •
Mars sol on Earth •
Mars sol on Mars • abnormal environmental cues (i.e.: unnatural light exposure) ==Sleep loss, genetics, and space==