You think your commute’s rough? I don’t want to minimize your experience, but our space rovers have it much harder. It turns out that places like the Moon and Mars can tear up even our best hardware over time, as evidenced by this selfie capped by the Curiosity rover back in 2013 – just a year after it landed. But our scientists take this stuff and learn from it, and are already at work on the next set of tires for the planned Mars 2020 Rover.
What makes the newest set of tires so special is the shape-memory alloy they’re built from. When we buy tires down here, we’re mostly concerned with grip and durability, but the ones we send up to space have a different set of priorities. They have to perform well on both ultra-fine sand and on sharp, jagged rocks. They also have to both be light and able to carry a heavy (relatively speaking) payload. These Mars Spring Tires, built by NASA Engineer Colin Creager and Materials Scientist Santo Padula, are managing to do all of that.
Shape-memory alloy is, as the name suggests, a material that remembers its shape. Shape-memory materials can take some brutal deformation and return back to their original shape. Engineers test each aspect of a potential rover piece extensively, doing things like simulating Martian terrain as closely as possible. These new tires, built from a nickel-titanium alloy, can deform all the way down to the axles and pop right back to their original shape.
The Mars Spring Tires “allow rovers to explore greater regions of the [Martian] surface than currently possible,” says the MST website. “Secondly, because they conform 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 rover.
The potential for this to change Earth-bound vehicles is huge. Everyday inventions like scratch-resistant lenses and even the original digital sensor that our phone cameras are descended from came directly from the needs of space exploration. A tire like this could not only change the way heavy-duty vehicles work on rough terrain, but could even make their way into consumer cars one day. Flat tires would be a thing of the past, and tires could last decades instead of just a few years.