Circus 'Wall of Death' stunt may keep astronauts fit on the moon

As NASA prepares to send its first crew to the moon since 1972 and eventually establish a permanent lunar base, scientists have come up with an innovative way to counteract the toll space travel can take on the body: by getting astronauts to perform a daredevil circus stunt on the "Wall of Death."

The stunt involves traveling around the inside of a barrel-shaped wooden cylinder. Humans on Earth can't run fast enough to stay on the wall, so this scary feat is usually achieved using a motorcycle. 

However, on the moon, which has one-sixth of the gravity of Earth, astronauts could conquer the wall at running speeds of just 8 mph (13 km/h), according to new research, published May 1 in the journal Royal Society Open Science. This could help astronauts stay fit on the lunar surface, the scientists wrote.  

NASA intends to send astronauts back to the moon as early as 2025 and plans to establish a permanent lunar base to aid future space missions. But low-gravity conditions put less pressure on the bones and muscles, meaning they are likely to weaken and deteriorate faster than they would on Earth. 

Related: 'Space headaches' are a literal pain for astronauts. Why do they happen?

In the new study, two researchers, one male and one female, took on the nerve-wracking task of running round a 31-foot-diameter (9.5 meters) Wall of Death. The researchers were attached to a bungee cord that was suspended from a 118-foot-high (36 m) crane, which simulated lowering their body weight by around 83%, mimicking conditions of low gravity on the moon. 

Using data from this test, combined with treadmill data that evaluated how fast the researchers could run in varying gravity levels, the team predicted that running for just a couple of minutes at the beginning and end of each day would be enough to protect astronauts from microgravity-induced muscle and bone loss. 

"A training regime of a few laps a day promises to be a viable countermeasure for astronauts to quickly combat whole-body deconditioning, for further missions and home return," the team wrote in the paper. 

While the findings are promising, there are still several logistical challenges. For instance, shuttling a giant Wall of Death to the moon would be a difficult task. Instead, astronauts could run around the walls of circular homes to achieve these benefits, the authors suggest. However, early lunar habitats may not be big enough to accommodate this kind of training, and astronauts would still require specific training for other daily activities, experts who were not involved in the research told The Guardian. 

For the moment, the Wall of Death will remain a circus attraction rather than a key component of space travel. 

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