Fuel Cell

Stores fuel for the power plant. The fuel capacity is defined by the amount of volume allocated to it via the Design Property window.

A long time ago... (Before the Spacecraft Update)

It used to be a room. Didn't needed to be contiguous, and access to this room wasn't only unneeded, but impossible. This was the only room in which the game engine actually prevented you from placing a door or opening of any sort to.