Table of Contents

Living in Space

Sleeping in Space

CSA Astronaut Bjarni V. Tryggvason sleeps
on the Space Shuttle Discovery's mid-deck
floor. Image courtesy of NASA.

The best thing about sleeping in space is that you can do it anywhere. Due to the microgravity environment, sleeping on the floor is just as comfortable as sleeping on the wall, and astronauts don't require a mattress. Still, 45 percent of all medications used by space shuttle crews are sleeping pills. Some astronauts find sleeping in microgravity causes unfamiliar sensations, which combined with excessive light and noise creates poor conditions for getting a good night's rest. Studies such as the Canadian-led Sleep-Wake Immune Functions (SWIF), which was conducted aboard MIR, have aimed to learn more about sleeping in space.

A Day in Space

While orbiting the earth, astronauts experience 16 sunsets every 24 hours and a new 'day' approximately every 90 minutes. While 16 stunning sunsets is a treat for the astronauts, it poses a challenge to their regular sleeping patterns. Astronauts are allotted 8.5 hours for sleep during each 24-hour period, but many report that they only need 6 or 6.5 hours to feel fully rested. Some believe that this may be the result of the body feeling less fatigued as a result of being in a microgravity environment.

Astronauts use an Earth-based time zone, selected by Mission Control to keep a regular schedule. The majority of space missions are 'single shift', meaning that all the astronauts on the mission work and sleep at the same time. During periods when the shuttle is docked at the International Space Station (ISS), the mission may operate on a 'dual shift' schedule. Although efforts are made to put both crews on the same schedule, often the shuttle crew or the ISS crew will go to sleep and wake up several hours earlier.

Where Do Astronauts Sleep?

Some astronauts sleep in individual sleeping compartments that have a sleeping bag, pillow, light, air vent and a place for personal belongings. Those who prefer to sleep outside the units can secure their sleeping bags to the floor, the ceiling, or the wall, and may use earplugs and sleeping masks to block out the noise and light. To imitate sleeping on Earth, a sleeping bag with one slightly rigid side is used to mimic a mattress. Most astronauts use restraints to secure their limbs to their sleeping equipment or fold their arms across their chest to prevent them from floating above their heads. While it is not painful to have your arms float freely, many astronauts find this unsettling. Other astronauts, including Canada's first astronaut Marc Garneau, preferred to sleep "free floating". He would simply curl in the corner and doze off.

NASA Astronauts Catherine G. Coleman, Fred W. Leslie and
Michael E. Lopez-Alegria at the end of their sleep shift on the
mid deck of Space Shuttle Columbia. Image courtesy of NASA.

Wake-up Calls

It is a NASA tradition to have 'wake-up calls' for crew during shuttle missions. Each morning at the scheduled wake-up time, ground operations broadcast a song into the space shuttle cabin. A wide-range of musical styles is played including rock, pop, western and classical. Each song is selected for a particular astronaut. Sometimes the astronaut will request the tune, other times their family will select a song that has special meaning. Unfortunately, the wake-up service is only available on shuttle missions, and crewmembers living on the ISS must use a regular alarm clock.

See the list of songs played on Mission STS-100, in which CSA astronaut Chris Hadfield served as Mission Specialist #1.

For more information about sleeping in space, visit NASA's Human Spaceflight website.