Hydrazine

is one of the Resources in Astroneer. It can either be mined from veins in the surface or in the first levels of caverns or extracted from the air using a Fuel Condenser module.

Hydrazine is used as fuel for the Shuttle and the Spaceship.

It's very useful for trading on the Trade Platform because you can get it so easily with the Fuel Condenser. It has a sale value of 1.