CLEVELAND—When it comes to designing tires for worlds other than Earth, forget elongation and rebound and instead think "stoichiometric" and "shape memory alloys."
Scientists at NASA's Glenn Research Center near Cleveland have developed a non-pneumatic, compliant tire made of a stoichiometric nickel-titanium mesh that they envision will be used on a possible mission to Mars.
Stoichiometry is defined as a branch of chemistry that deals with the application of the laws of definite proportions and of the conservation of mass and energy to chemical activity.
The innovation, called the Superelastic Tire, is the latest evolution of the "spring tire" that NASA Glenn and Goodyear developed a few years back, inspired by the Apollo program's lunar-rover tires.
The latest version uses "shape memory alloys" capable of undergoing high strain as load-bearing components, instead of typical elastic materials, NASA Glenn said. This results in a tire that can withstand excessive deformation without permanent damage.
Using shape memory alloy as radial stiffening elements also can increase the tire's load-carrying capacity without a weight increase, NASA Glenn said.