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Nickel-titanium shape memory alloy spring tire designed for Mars rover
November 30, 2017
Source: ASM International
NASA Glenn Research Center, Cleveland, announces that its engineers have developed an airless compliant tire that consists of several hundred coiled wires of nickel-titanium shape memory alloy woven into a flexible mesh, giving the tires the ability to support high loads while also conforming to the terrain.
It is based on the "Spring Tire," which NASA developed with Goodyear back in the mid-2000s. However, rather than coiled steel wires woven into a mesh pattern (which was part of the original design), a team of NASA scientists has created a more durable and flexible NiTi version that could revolutionize space exploration.
After building the shape memory alloy tire, the Glenn engineers sent it to the Jet Propulsion Laboratory, where it was tested in the Mars Life Test Facility. Overall, the tires not only performed well in simulated Martian sand, but also were able to withstand going over punishing rocky outcroppings without difficulty. Even after the tires were deformed all the way down to their axles, they were able to retain their original shape. They also managed to do this while carrying a significant payload, which is another prerequisite when developing tires for exploration vehicles and rovers.
The priorities for the Mars Spring Tire (MST) are to offer greater durability, better traction in soft sand, and lighter weight. As NASA indicates on the MST website (part of the Glenn Research Center's website), there are three major benefits to developing high performing compliant tires like the Spring Wheel:
"First, they would allow rovers to explore greater regions of the surface than currently possible. Secondly, because they conform to the terrain and do not sink as much as rigid wheels, they can carry heavier payloads for the same given mass and volume. Lastly, because the compliant tires can absorb energy from impacts at moderate to high speeds, they can be used on crewed exploration vehicles which are expected to move at speeds significantly higher than the current Mars rovers."
The first available opportunity to test these tires out is just a few years away, when NASA's Mars 2020 Rover will be sent to the surface of the Red Planet. Once there, the rover will pick up where Curiosity and other rovers have left off, searching for signs of life in Mars' harsh environment. The rover is also tasked with preparing samples that will eventually be returned to Earth by a crewed mission, which is expected to take place sometime in the 2030s.
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