Tyres on the moon

Goodyear is working with NASA's Glenn Research Center (GRC) to develop non-pneumatic tyres for use on the moon and eventually on Mars.

'Lunar tyres need to be designed to develop traction on sandy undulated terrain, in regions that humans have never even seen up close,' said NASA Principal Investigator Vivake Asnani.

Asnani 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 that the US would embark on an initiative to further explore the moon and Mars.

Goodyear was selected to work with GRC because of its experience in previous lunar programs, understanding of vehicle dynamics and computer modelling capabilities.

The Goodyear team working on the new tyres consists of a cross section of research and tyre technology associates at its Akron Technical Center. In the past year, Goodyear has been evaluating the Apollo lunar rover wheel, prototype pneumatic tyres and non-pneumatic concepts to build an understanding of the mechanics of the wheels and the challenges of the lunar environment.

While a one-year timeline to develop and demonstrate something as novel as a lunar tyre seems extremely aggressive, the group is building on technology from the first moon landing. In the 1960s, NASA funded over 10 years of intensive research at Goodyear and General Motors to develop the wire mesh moon tyre for the Apollo Lunar Roving Vehicle (LRV).

The LRV tyre 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 tyre. The approach worked well, because each LRV tyre was only required to support about 60 pounds of weight and be used for a maximum of 75 miles.

The new fleet of lunar vehicles will require tyres to support about 10 times the weight and last for up to 100 times the distance.

To extend the utility of the wire mesh tyre, the team is first analyzing the original design using computer modelling tools. Furthermore, exact replicas of the tyres are being manufactured and tested to find out how and why their load and life are limited.

The Goodyear tyre designers and research engineers at NASA GRC will then iteratively design, build, and laboratory-test concept tyres to mitigate the failures.

A set of 12 tyres will be built by winter of 2009 and demonstrated on the new NASA Chariot roving vehicle at the Johnson Space Center in Texas. (see http://robonaut.jsc.nasa.gov/chariot/ for more details.)