NASA has developed a new tyre that can travel without problems on difficult terrain, such as the surface of Mars. It is made of a special kind of nickel-titanium that 'remembers' its shape.
The space agency has been looking for good wheels for its vehicles for years and they are needed now more than ever. The newly designed super-elastic tyre is supposed to be an alternative to the pneumatic tyres currently used on the Mars Curiosity Rover, the vehicle NASA uses to explore the planet. The Rover itself is doing well but the Curiosity's wheels have already suffered considerable damage due to the difficult terrain.
Teeth in wheels
The design was made at the NASA Glenn Research Centre in Cleveland, Ohio. A wheel made of spring steel already came to fruition there some nine years ago. The various prototypes made from it proved to have great grip in soft sand and could also support a lot of weight. Yet they did not remain unscathed on Mars' simulated terrain. When the tight steel wire mesh came under pressure, plastic deformation occurred and the entire tyre lost its shape.
Also on Earth
A solution finally emerged when a materials specialist visited the research centre above. He had long been working with alloys with "memory properties" and suggested that this might also be suitable for the new wheels of vehicles like the Mars Curiosity Rover. Together, they worked on a prototype tyre based on a superelastic nickel-titanium alloy that remembers its shape. The tyre was found to shoot back into its original shape even when it was extremely (to the axle) dented or deformed. 'This material has the ability to create an atomic rearrangement to accommodate deformation, and we think this tyre is going to revolutionise when it comes to space vehicles. But they can also be used for vehicles on Earth.' NASA is thinking of wheels military vehicles, aircraft and agricultural vehicles, among others.
Although much development is still needed, NASA believes that memory metal has a lot of potential in the future. 'There are three big advantages when it comes to developing high-performance conformal bands that we can deploy in areas like from Mars or the moon. First, rovers can explore larger areas than currently possible, second, they can adapt to the terrain without sinking into it, allowing them to carry more weight. And finally, the tyres can extract energy from medium- to high-speed impacts, making them also suitable for higher-speed vehicles.' The tyres are also easier to assemble as they have no inner frame and offer more flexibility in terms of design options.
By: Kelly Bakker
Source: NASA
