Nitinol is an alloy of Nickel and Titanium. It's a smart material which remembers its shape https://www.sae.org/publications/technical-papers/content/851322/ Space Applications of Nitinol Heat Engines The Nitinol Heat Engine (NHE) uses a shape-memory alloy of nickel and titanium to convert thermal energy directly to mechanical power and through a generator, to electricity. An NHE was analyzed and designed to produce power from solar irradiation in space, with radiative coolin