Correspondence, Alix VERMANDE.
As part of a call for tenders launched by NASA, the Michelin group has entered the race to design lunar tires to equip vehicles for future space missions.
World leader in tire manufacturing, the Michelin group aims even higher. Much higher. The Auvergne company has been working for several years on the creation of tires for driving… on the Moon.
As part of the Artemis mission, Michelin, which already maintains good relations with NASA, responded to a call for tenders from the American space agency. It was not a first. “The story between Michelin and NASA began in 1995 when we began to equip the American space shuttle with tires for landing, recalls Florian Vilcot, innovation expert and in charge of the Artemis project. This was our first contact with NASA. It led us to initial research in the years 2006-2009 concerning the development of a wheel for a very different lunar vehicle. Our partners came to see us in 2021 to join the “Intuitive Machines” design team, in order to develop a new lunar vehicle as part of the Artemis project. »
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Resisting the lunar climate
After taking a final step at the beginning of April, there is now one year left to convince the Americans, as part of a competition with two other consortia. This requires meeting the complex requirements of the program. Among which is the forecast of a ten-year mission for the lunar vehicle. The tires of which must therefore maintain a certain performance.
“On the Moon, the vehicle and the wheels will not be protected by the Earth’s atmosphere, so they will be exposed to UV rays in much greater quantities than on Earth. They will be exposed to electromagnetic radiation and radiation coming from the sun. These radiations can modify the performance of the vehicle as well as the wheels. We must take these elements into account in our design,” explains Florian Vilcot.
But there are many other parameters to take into account. “We need to imagine a wheel and tread with good abrasion resistance. Indeed, at the lunar South Pole, the sand has been eroded very little, so it is very sharp and very aggressive. The wheel will have to endure 10,000 kilometers. Among its missions, the vehicle will allow astronauts to descend into craters. This is where researchers hope to find water in the form of ice in permanently shaded areas. The wheel must withstand temperatures of -240°C to +100°C. Michelin therefore imagines solutions that use high-tech materials capable of withstanding this temperature range. »
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Tests in the Auvergne volcanoes
Furthermore, the lunar vehicle will have to move on sandy slopes of up to 20°. Michelin’s international team, made up of around ten experts in tire design, materials and testing, must design a wheel that will lay flat to generate the largest possible contact patch surface.
“If we want to take an image, we can draw a parallel with snowshoes that we adopt in powder snow to walk, in order to sink less and move forward more easily. The contact pressure with the ground is of the order of 0.05 bar to 0.1 bar. This is about the amount of pressure a physical therapist applies when giving a recovery massage. It’s really weak. It has nothing to do with the pressures that can be encountered on Earth,” completes Florian Vilcot.
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The latter is also pleased to see the prototypes being tested locally. “We test our wheels in the Auvergne volcanoes. We have a local playground that allows for ground conditions similar to those on the Moon. It is a Source of great pride for the entire team and it is a profession of passion. »
And this work on tires for driving on the moon would also be very useful for terrestrial designs. “These questions of traction, endurance and energy consumption, we find them when we develop a good agricultural tire or when we want to drive on sand or mud. »
