It was in 2019 that Bridgestone announced that it will take part in an international space exploration mission together with the Japan Aerospace Exploration Agency (JAXA) and Toyota Motor Corporation (Toyota). Now if you're wondering what a tyre company can possibly have to do with going to the moon -- the Japanese lunar mission set to take off around 2029 involves a plan to land an enclosed, pressurized rover that will hold two to four astronauts on the moon’s surface. This rover, if everything goes according to plan, will ultimately travel more than 6,000 miles on the moon! And that is where my friends, tyres come into play.

You see Bridgestone's involvement in this mission will include researching the performance needs of tyres for use on manned, pressurized rovers to help these rovers make better contact with the surface of the moon. Toyota is working with JAXA to build the majority of its rover for the lunar mission that wishes to achieve the pinnacle in terms of lunar human activity and simultaneously develop intellectual property on space exploration.

A much heavier craft, and the vastly increased travel distance, create some unique challenges that will take years of engineering to sort out, but Bridgestone already has a prototype model, which it showed off in-person at this year’s Consumer Electronics Show.

The original lunar rover wheels boasted of a zinc-coated, piano-wire mesh shell as a support structure to bear the weight of the craft. This shell was then riveted on the outside with titanium treads, in a specific arrowed pattern, to increase traction on the moon’s loose terrain.

For the much larger JAXA craft however, Bridgestone has created a prototype wherein a single tyre is composed of two tyre like structures that appear to be stuck together, with an outer shell outer shell that appears to be made of a steel wool-like material that’s formed into thick ropes. “It’s biomimicry,” says Bridgestone America’s chief technology officer, Nizar Trigui, noting that they were inspired by a camel’s hoof. “The pattern helps the tire carry the load without penetrating too deeply into the sand.”

Underneath the "hooved" surface, Bridgestone will be relying on a network of metal slats that flex like springs as the wheel moves along. When asked why the company wasn't trying out the honeycomb structure -- a popular design seen on most concept airless tyres, this is what they had to say:

“You don’t need a honeycomb structure because of the moon’s low gravity. Keeping the weight down is already a unique challenge.”

Also See: Bridgestone Bringing Airless Tyres To Bicycles And Fleets Soon

The metal rope structure and the heavy plates in the internal construction will mean that the lunar tyre will be quite heavy. However, this isn't really a bad thing as the moon isn’t exactly the most tyre friendly place in the universe. In addition to the massive temperature swings, the surface of the moon is home to some of the most difficult extra terrestrial terrains encountered by human civilization. There's no doubt that the astronauts will be fine with a tad more rolling resistance as long as they don't have to deal with a flat on the moon!

“The particles are fine, electrocharged, abrasive, and sharp,” says Trigui. “The materials need to be robust to all of that."

To make sure the tyres will be able to withstand the tough conditions on the moon, Jaxa, Toyota, and Bridgestone will test the lunar tyres in simulators that can replicate conditions and surfaces on the moon. Details regarding which moon simulation provider they will use for the tests have yet to be disclosed by the companies. One popular company that does offer such services goes by the name of "Off Planet Research" wherein they employ materials such as basaltic cinder and crushed glass to simulate authentic moon conditions.

There is still a lot of time before the mission and the final tyres to be fitted on the rover might look nothing like the concept showcased by Bridgestone. However, it'll be really interesting to see what the R&D in the lunar mission can do for the tyres on our own planet. Who knows, maybe hooved airless tyres will end up being the next big tyre revolution that we witness.

Source: popsci.com