NASA invented a magnetic liquid to pump rocket fuel without gravity

In 1963, NASA engineer Steve Papell patented a liquid packed with nanoscale magnetic particles that could be pumped and steered by magnets in zero gravity. The same ferrofluid now spikes into dramatic peaks whenever a magnet sits nearby, a party trick that is really surface-tension physics responding to a magnetic field.

— Steve Papell / NASA, Ferrofluid — US Patent 3,215,572, filed 1963