Andreas Mogensen will be working while asleep in space

Andreas Mogensen is ready for another trip to the ISS. The launch in planned in July 2023. Illustration: Sarah Christine Nørgaard/Ritzau Scanpi

When Andreas Mogensen goes on his second mission on the International Space Station (ISS) in a year, he will bring along a small earplug with advanced EEG measuring equipment made in Aarhus.

Monitoring of the Danish astronaut’s brain activity will provide sleep researchers with more knowledge about the difference between sleeping on Earth and in space, and the purpose of the “Sleep in Orbit” project is to help astronauts get better sleep and thus be able to better cope with the tasks and the hard everyday life in space—both physically and mentally.

Astronauts sleep poorly

It is already known that astronauts sleep significantly worse in space than they do on Earth. Their circadian rhythm and sleep patterns are disturbed by both living without gravity and the lack of a natural day-night cycle.

Poor sleep is the issue that most astronauts report having suffered while in orbit around Earth.

“Sleep is a kind of biomarker for our health and well-being. In fact, a great many diseases also impact the way we sleep, including a wide range of psychiatric disorders and neurodegenerative diseases. In general, however, there is no clear correlation between experienced sleep quality and physiological sleep. But physiological sleep is what’s crucial to our cognitive functions,” says Professor Preben Kidmose, head of Aarhus University’s Center for Ear-EEG, which has developed the small EEG earplug that will provide data for the “Sleep in Orbit” project.

The earplug is an EEG measuring device that can measure the electrical activity in the brain. Illustration: Lars Kruse, Aarhus Universitet

An EEG or electroencephalogram is usually performed with electrodes placed around the whole cranium, but researchers from Aarhus University have developed a device that is small enough to sit in the ear and at the same time sensitive enough to measure the brain’s electrical activity by detecting extremely small voltage changes on the surface of the skin inside the ear.

Long-term sleep measurements

“We’ve been working on developing ear-EEG technology for more than 15 years as a way of measuring electrical activity from the brain outside a laboratory. And it turns out that ear-EEG is extremely good at characterizing our sleep. This technology gives us a unique opportunity to conduct long-term measurements of brain activity. And that means we can begin to study things that we otherwise wouldn’t be able to measure. For example, we don't really know much about how our sleep varies over time, and how it’s affected by our surroundings,” Preben Kidmose says.

According to Eskild Holm Nielsen, dean of the Aarhus University Faculty of Technical Sciences, the project is important because we will probably be in space a lot more often and for a much longer time in the future.

“And it’s important to understand how it affects our sleep. And being able to make a precise physiological characterization of the sleep will also help us find out how we can help astronauts get a better night’s sleep in space. Professor Kidmose’s technology is a classic example of how technical sciences develop solutions that help people. I really look forward to following the progress of the project,” he says.

Andreas Mogensen will spend about half a year on the ISS. The data collected from him sleeping in space will also be analysed at Aarhus University, which will develop algorithms for the more long-term monitoring of sleep patterns—made possible thanks to the device that can be worn almost without even being noticed.