Sleeping will be one of the challenges for astronauts on missions to Mars

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Astronauts have been adjusting to the challenges of sleeping in space for years, and the lessons learned from their zero-gravity dreams will ensure that one day the first manned missions to Mars will have had enough rest before exploring the red planet.

Rotating crews have spent an average of six months living and working aboard the International Space Station for nearly 23 years, and they struggle with sleep problems just like people on Earth. Some of the challenges are similar to those for shift workers or people with abnormal hours, but others are more unique to the space setting.

For example, most people don’t have to worry about floating away from their beds due to zero gravity. Don’t worry, astronauts use special restraints to keep them from floating. through the space station while you sleep.

Two of the biggest challenges for astronauts include their sleep environment and establishing a natural sleep cycle.

Astronauts have dark, quiet and private crew quarters on the space station that allow them to sleep well, but that won’t always be the case on other space missions, said Dr. Erin Flynn-Evans, director of the Fatigue Countermeasures Laboratory. at NASA Ames Research. Center in Mountain View, California.

Like their historic Apollo predecessors, the Orion capsules to be used during future Artemis missions to the Moon are small vehicles with limited space for crews and sleeping bags for rest periods.

“I think it’s like camping,” Flynn-Evans said. “If it’s for a couple of days, it’s probably not a big deal. But the longer you’re in enclosed spaces with someone, the more disruptive it can be.”

While the space station offers incredible views of Earth, the 16 sunrises an astronaut witnesses a day can wreak havoc on the circadian rhythm, the body’s natural sleep-wake clock.

On Earth, disruptions in the circadian rhythm occur for people who work night shifts or experience jet lag while traveling across time zones.

“Light is what resets our circadian rhythm and keeps us organized in that day/night cycle, but in space we have a number of challenges,” Flynn-Evans said.

The space station orbits Earth every 90 minutes, creating alternating cycles of darkness and light. Rather than force astronauts to adjust to such a bizarre cycle, NASA experts added lighting inside the space station that mimics what people experience during a normal day on Earth.

“We have to try to block the light from the windows at night,” he said, “and we really have to try to maximize the light through the windows or with internal lighting to make sure that the crew gets that synchronization stimulus so that they are able to stay awake and asleep at the right time”.

Jet lag begins before astronauts arrive at the space station, and their sleep schedules are shifted for days before liftoff based on the time of day and time zone they will be taking off from. Once they arrive at the space station, each astronaut is transferred to Greenwich Meridian“a good middle ground between all the countries participating,” said Flynn-Evans.

At the Fatigue Countermeasures Laboratory, Flynn-Evans and his colleagues develop tools to help astronauts overcome sleep challenges. Some of the strategies involve managing when astronauts are exposed to blue light, the main timing wavelength for the circadian system, and when to reduce blue light to help them sleep.

Astronauts have regular schedules, but the arrival of resupply missions or new crews sometimes interrupt them. Flynn-Evans and other researchers develop approaches to safely shift sleep for astronauts, such as determining when to nap or stay up later to accommodate time changes.

The same tips that help astronauts sleep also apply on Earth, including following a regular time to wake up and fall asleep at the same time as much as possible and limiting exposure to blue light before bed, which is emitted by televisions. LEDs, smartphones, computers and tablets.

Although scientists have sleep data from years of spaceflight, running simulations Missions on Earth allow for greater control.

“We do fake space missions all the time,” Flynn-Evans said. “We have what we call an analog space environment at the Johnson Space Center called a Human Exploration Research Analog, or HERA, and that’s basically a small habitat.”

The habitat mimics the size of a lunar base or small spacecraft and can house crews of four for long periods of time. Flynn-Evans participated in a study in which crews spent 45 days in the habitat and were restricted to five hours of sleep on weekdays and eight hours on weekends. Participants were tested for alertness and performance.

The experiment’s findings showed that if crew members only got five hours of sleep a night, they needed more opportunities to catch up on subsequent nights to avoid the deleterious effects of sleep deprivation. The current requirement is that crew members earn 8½ hours of sleep per night on missions to prevent long-term sleep loss, fatigue-induced errors and health complications, according to NASA.

In June, NASA will begin the first experiment in a new 3D-printed Martian habitat at the Johnson Space Center called the Crew Health and Performance Exploration Analog, or CHAPEA.

Over the course of a year, a four-person team will live and work within a 1,700-square-foot (158-square-meter) space to simulate life on Mars. Focus because the first experiment is nutrition, but Flynn-Evans and her fellow researchers will also monitor how well the crew sleeps.

Habitats like HERA and CHAPEA allow scientists to simulate surprises that can occur on a real mission to the Moon or Mars, such as limited resources, faulty equipment, communication problems, and other stressors of small habitats.

An unexpectedly rich source of sleep data has been shown to be studying Earth scientists and engineers working on missions to Mars, such as the Perseverance rover.

A day on Mars is about 39 minutes longer than one on Earth, but that’s long enough for mission control on Mars to adjust. their schedules constantly to stay on the schedule of Perseverance.

“If you shift 39 minutes a day, that means you basically go to bed 39 minutes later every day,” Flynn-Evans said. “It doesn’t seem so bad in one night. But after five days, it’s like you’ve crossed, like, six time zones. It’s a real stressor on the body.”

There are still many unknowns about being in “Mars time”, such as how the change in time affects the metabolism of the human body.

Understanding how people on Earth adapt to living in Mars time is one way to prepare for future missions to the red planet. Flynn-Evans and her team are working closely with those planning Artemis lunar missions to optimize astronaut schedules and ensure sufficient lighting and muffled noise inside Orion when they need to sleep.

The researchers also want to study the amount of caffeine astronauts require to stay alert and make sure crews don’t run out of coffee on a spacecraft with limited storage.

“Sleep is closely related to performance, alertness, interpersonal communication and relationships,” Flynn-Evans said, “so we want to make sure crews are set up for success and get the sleep they need.” .