Dec 14 2007
Goodyear, the innovator of run-flat tire technology on Earth, is working with NASA Glenn Research Center (GRC) to significantly evolve the technology and take its capabilities to the rest of the universe. Part of a funded program by NASA's Innovative Partnership Program (IPP) to develop non-pneumatic tires for use first on the moon, and eventually on Mars, the IPP Seed Fund was established to advance key technologies to meet critical needs for NASA's missions.
Because of the unique atmospheric characteristics of the operational environment, "The basic rubber-pneumatic design used on Earth does not have the same utility on the moon," said NASA Principal Investigator Vivake Asnani. "The challenges associated with creating a lunar tire are further complicated by the fact that there are no lunar roads. Lunar tires need to be designed to develop traction on sandy undulated terrain, in regions that humans have never even seen up close. Plus, the prospect of an immobilizing 'flat tire' would be devastating to the mission."
Vivake is a founding member of the Surface Mobility Technology team at GRC that was created in late 2005 in response to the announcement by President Bush in 2004 that the United States would embark on an initiative to further explore the moon and Mars. Vivake said Goodyear was selected to work with GRC because of its experience in previous lunar programs, understanding of vehicle dynamics and state-of-the-art computer modeling capabilities.
Goodyear engineers are used to thinking out-of-the-box in terms of developing entirely new technologies, so thinking "out-of-this-world" was not a stretch, according to Joe Gingo, Goodyear's executive vice president and chief technical officer. "The mission performance goals for these tires will push known tire technology well beyond its comfort zone," Gingo said, "and I am confident we have the capabilities to do that."
Goodyear Principal Investigator Dave Glemming said the decision to partner with NASA for this initiative was easy. "Not only will the outcome of this project deliver a product that can handle the performance capabilities required for lunar mobility and beyond, we expect the outcome will yield answers to how future non-pneumatic tires may be designed for Earth applications."
The Goodyear team will consist of a cross section of research and tire technology associates at the Akron Technical Center. In the past year Goodyear has been evaluating the Apollo lunar rover wheel, prototype pneumatic tires and non-pneumatic concepts to build a baseline understanding of the mechanics of these wheels and the challenges of the lunar environment.
While a one-year timeline to develop and demonstrate something as novel as a lunar tire seems extremely aggressive, the group is building on technology from the first moon landing, Glemming said. In the 1960s, NASA funded over 10 years of intensive research at Goodyear and General Motors to develop the wire mesh moon tire for the Apollo Lunar Roving Vehicle (LRV).
The LRV tire was woven out of piano wire, in order to provide a soft, springy surface to contour to the ground and provide good ride quality. It looks a bit like the skeleton of an Earth tire. This approach worked very well, because each LRV tire was only required to support about 60 pounds of weight (all things weigh 6x less on the moon than on Earth) and be used for a maximum of 75 miles. The new fleet of lunar vehicles will require tires to support about 10 times the weight and last for up to 100 times the distance. A tire that would meet such requirements would also be useful for commercial applications on Earth, Glemming said.
To extend the utility of this wire mesh tire, the team is first analyzing the original design using computer modeling tools. Furthermore, exact replicates of the tires are being manufactured and tested to find out how and why their load and life are limited. Essentially, the tires will be loaded and cycled until they fail. The Goodyear tire designers and research engineers at NASA GRC will then iteratively design, build, and laboratory-test concept tires to mitigate the failures. The exact nature of these design changes has not been disclosed yet. Following in the NASA tradition, everything will be proven and nothing taken for granted. A set of 12 tires will be built by winter of 2009 and demonstrated on the new NASA Chariot roving vehicle at the Johnson Space Center in Texas.