What name does Grace give to the material in Rocky's ship?

Grace calls the material in Rocky’s ship “xenonite.”

Xenonite is an extremely strong, heat-resistant material associated with the Eridians, Rocky’s species. Rocky’s vessel, called the Blip-A by Grace, is largely constructed from it. Grace gives the substance its name because he needs a usable term while studying an alien material with no established human equivalent.

The material is important beyond simple spaceship construction. Grace and Rocky use xenonite to build equipment for collecting Taumoeba from the atmosphere of Adrian, a planet in the Tau Ceti system. Its unusual properties make it valuable for surviving hostile temperatures, pressure, and chemical conditions.

A common mix-up is to choose “astrophage,” the star-consuming organism that powers the ships. “Petrova line” names the infrared phenomenon created by astrophage movement, while “Taumoeba” is the organism that preys on astrophage. Xenonite is the ship material, not a life-form or energy source.