Answer: Spermaceti

In the 19th century, long before the advent of highly refined petrol-based and synthetic lubricants, there was a pressing need for high quality machine lubricants. The most prized natural lubricant available was the waxy substance from the spermaceti organ of sperm whales. The substance found inside—technically a type of wax and not an actual oil—was an astoundingly good lubricant since it was thin, didn’t congeal or dry out, didn’t corrode metals, could withstand high temperatures, and even had a low freezing point.

As a result of all these desirable properties, spermaceti (also referred to as sperm machine oil) has been used over the last two hundred years in a very diverse range of applications including lubricating sewing machines, inside locomotive engines and, later, automotive transmissions. Although it has long since fallen out of favor as a general use lubricant, it still remains a critical component in several rather high-tech fields, including aerospace engineering. NASA has yet to find a lubricant that works as well in the deep chill of space as spermaceti and it has been used to lubricate a wide variety of NASA’s projects like the Hubble Space Telescope and the Curiosity Rover.