Any rover travelling across the rocky surface of Mars requires extremely durable wheels. NASA’s Perseverance, for example, has aluminium wheels with spikes for better traction. However, NASA researchers always look for ways to improve. Now they are working on creating a new generation of wheels for future Mars rovers. One such promising development is wheels that emphasise flexibility rather than stiffness.
According to NASA, engineers at the Glenn Research Centre in Ohio have tested the latest spring tires made from Shape Memory Alloy, or SMA for short. This nickel-titanium based alloy is capable of restoring its shape after deformation or temperature changes. Unlike solid tires, SMA alternatives resemble a tightly interlocked mesh cage.
Santo Padula, a materials engineer at NASA, has been working on SMA for years, but only recently saw the technology’s potential for Mars rovers. The idea came about during a visit to the Simulated Lunar Operations (SLOPE) Laboratory, where he saw prototype Mars rovers. Padula immediately noticed the problem with steel wheels – their tendency to deform irreversibly.
“I have a solution. I’m developing an alloy that will solve this,” said Padula, and that’s how the SMA tires came to be.
Together with Colin Creager, a NASA engineer, the team worked to adapt the SMA for Martian conditions. The tires were tested in a Martian soil simulator at the Airbus Defence and Space facility in the UK last autumn. The tests included ascents, descents, driving on rocks and sand. “We focused on stability, because that was important for the new environment,” explained Creager.
According to NASA, SMA tire deformations were minimal and in line with expectations. Padula said the goal was to expand the temperature range of SMA use, as well as explore its potential for other projects, particularly habitat protection.
Future rovers with SMA wheels could be useful not only for missions to Mars, but also to the Moon. In addition, alloys can be used in the creation of lunar bases. For example, the outer layer of the SMA is capable of withstanding micrometeorite impacts, which is particularly relevant for lunar operations.
We previously reported on how the Perseverance’s off-road capability impressed NASA engineers.
According to popsci.com
