08 January 2013

Study Finds Sleep Patterns And Neurobehavioral Effects As A Concern On Manned Mission To Mars

Researchers analyzing data on the the sleep, performance, and mood behavioral impact of deep space travel to astronauts find that sleep patterns and neurobehavioral effects on the crew members must be addressed for successful adaption to prolonged space missions.

For quite some time, Mars has been a hot topic when it comes to sending humans into outer space. Just recently, NASA's Mars Curiosity Rover landed on Mars and have been taking tests of the surface of the planet. It has even picked up what might possibly be evidence of water on Mars.

Travelling to Mars takes lots of preparation. For one, there are only four windows of opportunity that cycles every fifteen years to require the least amount of energy to transfer from an Earth orbit to the Mars orbit.

The next window for a low energy orbit transfer would occur in 2018.

It would take roughly 250 days to travel from the Earth to Mars. During the trip, astronauts are exposed to dangerous cosmic radiation, space debris, a zero gravity environment and even psychological effects from prolonged isolation.

The United States delayed its plan to send astronauts to Mars by 2020. Instead, the plan is to send a manned mission to an asteroid in 2025 and plan for a Mars trip by 2030.

Mars One, a private endeavor to set up a human colony on Mars led by Dutch entrepreneur, Bas Lansdorp, was announced on June 2012. The project's plan is to land humans on Mars to establish a permanent settlement in 2023. A new set of four astronauts would then arrive every two years.

Mars One is set up to be a one way trip to Mars for the astronauts.

Impact of Prolonged Space Travel To Mars On Astronauts

In the first study of its kind, a team of researchers led by faculty at the Perelman School of Medicine at the University of Pennsylvania and the Baylor College of Medicine, has analyzed data on the impact of prolonged operational confinement on sleep, performance, and mood in astronauts from a groundbreaking international effort to simulate a 520-day space mission to Mars. The findings, published online-first in the Proceedings of the National Academy of Sciences, revealed alterations of life-sustaining sleep patterns and neurobehavioral consequences for crew members that must be addressed for successful adaption to prolonged space missions.

"The success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of astronauts to remain confined and isolated from Earth much longer than previous missions or simulations," said David F. Dinges, PhD, professor and chief, Division of Sleep and Chronobiology in the Department of Psychiatry at the Perelman School of Medicine, and co-lead author of the new study. "This is the first investigation to pinpoint the crucial role that sleep-wake cycles will play in extended space missions."

The 520-day simulation, which was developed by the Institute for Biomedical Problems (IBMP) of the Russian Academy of Sciences, and sponsored in part by the European Space Agency (ESA), was initiated on June 3, 2010 when the hatches were closed on a 550-cubic-meter IBMP spacecraft-like confinement facility in Russia. The simulated mission, involving an international, six-man team of volunteers, involved more than 90 experiments and realistic scenarios to gather valuable psychological and medical data on the effects of a long-term deep space flight. The 520-day mission was broken into three phases: 250 days for the trip to Mars, 30 days on the surface, and 240 days for the return to Earth.

As the only U.S. research team involved with the Mars 520-day simulation, the study authors monitored the crew's rest-activity patterns, and performance and psychological responses to determine the extent to which sleep loss, fatigue, stress, mood changes and conflicts occurred during the mission.

Video: Searching for the ideal crew for manned mission to Mars

Measurements included continuous recordings of body movements using wrist actigraphy (a noninvasive means of estimating sleep and movement intensity), and light exposure and weekly computer-based neurobehavioral assessments to identify changes in the crew's activity levels, sleep quantity and quality, sleep–wake intervals, alertness performance, and workload throughout the 17 months of mission confinement.

Data from the actigraph devices revealed that crew sedentariness increased across the mission, as illustrated by decreased waking movement and increased sleep and rest times. The majority of crewmembers also experienced one or more disturbances of sleep quality, alertness deficits, or altered sleep–wake intervals and timing, suggesting inadequate circadian synchronization.

"Taken together, these measurements point to the need to identify markers of differential vulnerability to abnormal decrease in muscular movement and sleep– wake changes in crew members during the prolonged isolation of exploration spaceflight and the need to ensure maintenance of the Earth's natural circadian rhythm, sleep quantity and quality, and optimal activity levels during exploration missions," said Mathias Basner, MD, PhD, MSc, assistant professor of Sleep and Chronobiology in Psychiatry at Penn and co-lead author.

The research team concludes that successful adaptation to such missions will require crews to transit in spacecraft and live in surface habitats that artificially mimic aspects of Earth's sleep-wake activity cycles, such as appropriately timed light exposure, food intake, and exercise. This dynamic will be necessary to maintain neurocognition and human behavior throughout the flight.

The findings also have implications for the increasing prevalence of sleep and circadian rhythm disorders in mainstream society. The research team notes that many people in industrialized societies exist with sedentary lifestyles, prolonged artificial light exposure, and disruptions in healthy sleep patterns due to education and work schedules, leading to other comorbid health conditions such as obesity.

"A takeaway message from this line of research is the life-sustaining importance that healthy sleep duration and timing plays for everyone," Dinges said. "As a global society, we need to reevaluate how we view sleep as it relates to our overall health and ability to lead productive lives. Whether it is an astronaut being challenged to reach another planet or a newborn baby just learning to walk, the human body's need for sleep is as essential as our need for food and water and integral to our ability to thrive."


University of Pennsylvania School of Medicine
Proceedings of the National Academy of Sciences
Baylor College of Medicine
European Space Agency (ESA)
National Aeronautics and Space Administration (NASA)
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