Bridgestone taking NPT development out of this world

TOKYO—Bridgestone Corp.'s tires have conquered some of the greatest challenges the roadways—and even those off-road spaces—have thrown at them.

So it's no surprise that the tire maker is looking to take its tire product development even farther.

Think 238,000 miles farther—all the way to the moon.

Tokyo-based Bridgestone is building its tire development experience and expertise as a part of two separate lunar vehicle development teams. In both cases, Bridgestone envisions playing a significant role in pushing lunar exploration even further by connecting Japanese Aerospace Exploration Agency (JAXA) and NASA lunar terrain vehicles to the moon.

Bridgestone announced in September that it signed an exclusive agreement to join the Teledyne Brown Engineering development team, which aims to design and build a lunar vehicle that supports NASA's lunar missions.

"This project is a bold new challenge for humanity, and we are honored to be joining the Teledyne Team," Makoto Ishiyama, executive director of Bridgestone's next generation technology development, said in a news release detailing the Teledyne Brown partnership. "This project will help us fulfill the 'Extension: Committed to nonstop mobility and innovation that keeps people and the world moving ahead.' Through this co-creation with new partners, the Bridgestone Group is dedicated to realizing the dream of humankind with mobility innovation."

In addition to Bridgestone, the Teledyne Brown team brings together North America Inc., Sierra Space Corp. and Textron Inc. to develop the unpressurized (unenclosed) rover to NASA's specifications.

Bridgestone's journey to develop nonpneumatic tires for lunar exploration is rooted in a 2019 partnership with JAXA. This project, Bridgestone said, focuses on the development of tires for a pressurized (enclosed) lunar rover designed by Toyota.

And according to Bridgestone Japan, that's a task much easier said than done.

On the moon, rubber just won't do. At least, not for tires.

The atmospheric temperatures—which range from -170°C to 120°C—make it difficult for elastomeric materials to perform optimally, especially when high-energy cosmic radiation is factored in.

So Bridgestone has turned to metal materials for the lunar tire structure.

"Bridgestone chose to make all-metal tires to perform in these harsh conditions," Bridgestone Japan told Rubber News in an exclusive interview. "The elastic metal skeleton construction is designed to bend flexibly, despite being made of metal, while offering the resilience necessary to make the trips of more than 10,000 kilometers required of moon exploration missions."

While the tire maker said that the JAXA project is at the "desk study" level, it did note that it has made significant strides in its understanding of the nonpneumatic lunar tire technologies.

Because while the metal materials can withstand the atmospheric pressures, the tire design needs to be able to manage the lunar terrain.

"The moon surface is covered in regolith, a layer of incredibly fine sandy deposits, meaning that high-contact pressure on the surface can result in tires being buried in this terrain and unable to move," Bridgestone Japan said about the JAXA tire design. "To address this issue, Bridgestone employed a double-tire structure in which two tires are attached to each wheel, like on large trucks, to increase the area of the tire's contact patch."

The resulting contact patch, Bridgestone said, is roughly six times greater than that of a standard passenger car tire, allowing for pressure to be dispersed across a much larger area.

"In designing these tires, Bridgestone took inspiration from camels, which can carry heavy loads across the desert with ease thanks to the pads on their feet," Bridgestone Japan said. "Mimicking this mechanism, the tires are encased with special tread material made from elastic metal like a steel wool, in order to disperse the contact pressure."

While there are significant differences between the lunar surface and the earth's surface, there also is a lot of crossover in the expectations of both earth and lunar tires. After all, lunar vehicles are vehicles that will need to brake, accelerate and corner just like their terrestrial counterparts.

Optimizing vehicle dynamics is a space where Bridgestone believes it has the experience to tackle some of the biggest lunar tire challenges.

"A significant challenge to developing tires for the lunar surface, as identified by JAXA and Toyota during the joint review process, is being prepared for the rover's grounding on the moon," Bridgestone Japan said. "Bridgestone's elastic wheel will not only support the vehicle's weight, acceleration, braking, changing and maintaining of direction, but also will absorb shock from the landing."

Designing and developing tires that best manage a vehicle's capabilities is the heart and soul of Bridgestone. It's a concept the company calls Shinshu-Dokuso, or creative pioneering. And it's a spirit that is woven into the tire maker's entire portfolio.

Creative pioneering, Bridgestone Japan said, is what drives the tire maker to ensure that it not only puts forth the best possible products, but the kind of products that can have the greatest impact on society.

That concept is especially relevant today, not only through the development of earth tires for every application, but for nonpneumatic and lunar tires as well.

Bridgestone contends that by maintaining its focus on that creative pioneering spirit, it illuminates opportunities to perfect its products for an auto industry transitioning to new mobility.

"Bridgestone has an extensive portfolio of innovative products and solutions to meet any kind of condition and has the expertise and technology necessary to develop the contact patch for road surfaces all over the globe," Bridgestone Japan said. "With the expertise and technology Bridgestone continues to obtain from participation in the Space Exploration Mission, Bridgestone will be able to continue to support the realization of new mobility."