As humans prepare to return to the moon after an absence of more than half a century, researchers have come up with a radical approach to keeping astronauts fit as they poke around the rocky ball.
To prevent lunar explorers from becoming weak and weak in a low-gravity environment, scientists suggest that astronauts go for a run. But this being space, it’s not just any kind of jogging – researchers have advised astronauts to run several times a day around the ‘lunar wall of death’.
Using a rented Wall of Death – a giant wooden cylinder used by motorcycle stunt riders in their gravity-defying fairground act – a 36-metre telescoping crane and a couple of bungee cords, the researchers showed that it’s possible for a person to run enough fast in lunar gravity to not only stay on the wall but also generate enough lateral force to combat bone and muscle loss.
“I’m amazed that no one had this idea before,” said Alberto Minetti, professor of physiology at the University of Milan. “It could be a convenient way to train on the moon.” And easier than building a rotating moon base that generates power, like the giant wheel of space First Station in 2001: A Space Odyssey.
Humans haven’t set foot on the moon since the end of the Apollo program in 1972, but NASA and other space agencies are preparing to return with long-duration missions to permanent habitats. NASA’s Artemis astronauts are due to fly around the moon next year, with a follow-up mission to the surface as early as 2026.
The hostile lunar environment presents several challenges, from providing astronauts with air, food and water to good protection against cosmic radiation. But without normal gravity to work against, astronauts lose bone and muscle mass, along with the fine nervous system control needed for coordinated movements, making measures to combat “deconditioning” a priority.
Minetti and his colleagues’ calculations show that it would be extremely difficult for humans to run around the Wall of Death on Earth without falling. But with the moon’s gravity, which is one-sixth that of Earth, the feat is much easier. According to his calculations, running at over 8 mph should be enough.
To test the idea, two researchers ran around a 10-meter-wide wall of death while attached to a bungee cord suspended from the crane. The setup emulates lunar gravity by taking five-sixths of their body weight. Combined with the treadmill data, the scientists concluded that running for a few minutes at the beginning and end of each day should generate enough lateral force, or “artificial gravity,” to keep bones and muscles healthy and maintain good nervous system control. .
Instead of transporting a real Wall of Death to the moon, astronauts could be housed in circular habitats, allowing them to run around the walls of their off-world homes, the team wrote in Royal Society Open Science.
“A horizontal moving cylinder certainly promises to be a useful countermeasure to prevent deconditioning in reduced lunar gravity,” said Maria Stokes, professor of neuromusculoskeletal rehabilitation at the University of Southampton. But specific training for daily life and work activities will still be needed, she added, to maintain certain skills and ensure astronauts work safely on the surface.
Nick Kaplan, professor of aerospace medicine and rehabilitation at Northumbria University, Newcastle, said the proposal was “certainly novel” but doubted whether early lunar habitats would have been large enough to accommodate such runways. With colleagues, he is working on new approaches to exercise in space and on the moon, including inflatable cuffs to compress limbs and restrict blood flow.
“Blood flow restriction exercise has been shown in Earth-based studies to produce similar muscle, bone, and cardiorespiratory training benefits typically seen with higher-intensity exercise at much lower exercise intensities and durations,” Kaplan said. “It could therefore make existing exercise countermeasures more effective at keeping astronauts healthy without the need for a lunar wall of death.”
