Awards Judges Pumped About Goodyear Airless Tyre

Should NASA ever get round to popping back to the moon or decide to dispatch a wheeled vehicle to Mars, it can make arrangements secure in the knowledge it has an award winning tyre to draw upon. On November 11, US based publication R&D Magazine held its 48th Annual R&D 100 Awards and named Goodyear Tire & Rubber, together with the NASA Glenn Research Center, a winner in its ‘mechanical devices’ category. The award was given for both parties’ work on the ‘Spring Tire’, an airless tyre capable of transporting large, long-range vehicles across the surface of celestial bodies.

The tyre, developed last year, is constructed out of 800 load bearing springs.  It is designed to carry much heavier vehicles over much greater distances than the wire mesh tyre (also co-manufactured by Goodyear) previously used on the Apollo Lunar Roving Vehicle in the early 1970s.  The new tyre, says Goodyear, could allow for broader exploration and the eventual development and maintenance of planetary outposts, and may even have applications on Earth.

According to Vivake Asnani, principal investigator for the project at NASA’s Glenn Research Center in Cleveland, to qualify for an R&D 100 Award the tyre had to meet a significant change in requirements that required innovation. “With the combined requirements of increased load and life, we needed to make a fundamental change to the original moon tyre,” he said.  “What the Goodyear-NASA team developed is an innovative, yet simple network of interwoven springs that does the job.  The tyre design seems almost obvious in retrospect, as most good inventions do.”

The Spring Tire was installed last year on NASA’s Lunar Electric Rover test vehicle and put through its paces at the “Rock Yard” at NASA’s Johnson Space Center in Houston where it was successfully trialled. “This tyre is extremely durable and extremely energy efficient,” noted Jim Benzing, Goodyear’s lead innovator on the project. “The spring design contours to the surface on which it’s driven to provide traction. But all of the energy used to deform the tyre is returned when the springs rebound.  It doesn’t generate heat like a normal tyre.”

Goodyear’s engineers relate that development of both the original Apollo lunar mission tyres and the new Spring Tire were driven by the fact that traditional pneumatic rubber tyres used on Earth have little utility on the moon.  This is because rubber properties vary significantly between the extreme cold and hot temperatures experienced in the shaded and directly sunlit areas of the moon. Furthermore, unfiltered solar radiation degrades rubber, and pneumatic tyres thus pose an unacceptable risk of deflation.

According to Asnani, the Spring Tire does not have a “single point failure mode.  What that means,” he said, “is that a hard impact that might cause a pneumatic tyre to puncture and deflate would only damage one of the 800 load bearing springs. Along with having this ultra-redundant characteristic, the tyre has a combination of overall stiffness yet flexibility that allows off-road vehicles to travel fast over rough terrain with relatively little motion being transferred to the vehicle.”