How a metal with a memory will shape our future on Mars

A rover on the Moon has metal wheels that can flex around rocky obstacles, then reshape back to their original form. On Earth, surgeons install tiny mesh tubes that can dilate a heart patient’s blood vessels all on their own, without mechanical inputs or any wires to help.

These shape-shifting capabilities are all thanks to a bizarre kind of metal called nitinol, a so-called shape-metal alloy that can be trained to remember its own shape. The decades-old material has become increasingly common in a wide range of everyday applications. And in the next decade, the metal will face its most challenging application yet: a sample return mission on Mars.

Nitinol, made of nickel and titanium, works its magic through heat. To “train” a paper clip...

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