A rover on the moon has metal wheels that can bend around rocky obstacles and then change back to their original shape. On Earth, surgeons install tiny mesh tubes that can dilate a heart patient’s blood vessels all by themselves, with no mechanical inputs or wires to help.
These shape-shifting capabilities are all due 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 is increasingly common in a wide variety of everyday applications. And over the next decade, the metal will undergo its most challenging application yet – a sample return mission to Mars.
Nitinol, made of nickel and titanium, works its magic through heat. For example, to “train” a nitinol paper clip, heat it to 500 degrees Celsius in the desired shape and then splash it in cold water. Bend it out of shape, then give back the same heat source, and the metal will eerily slide back into its original shape.
The temperature that triggers the transformation of nitinol varies depending on the finely tuned ratio of nickel to titanium. Engineers can modify the metal to adapt to a wide variety of conditions, making it an important tool in places where complex mechanics don’t fit, such as the blood vessels around a human heart or a hinge that positions a solar panel by responding to the Sun. Warmth.
The edge spoke with engineers at NASA’s Glenn Research Center to see how nitinol will play a role in a mission to retrieve humanity’s first cache of pristine Martian soil samples – the second part of a mission to Mars led by NASA and the European Space Agency. Watch the video above to learn how and to see nitinol in action. (We promise, it’s not CGI.)