Helium-3

Helium-3 is an isotope of helium that is used in nuclear fusion reactors, and as fuel for "fusion torches", which are the main commercial form of starship thruster.
For this reason, it is a key resource in the galactic economy. Helium-3 can often be found in the atmospheres of gas giants, from where it can be easily and cheaply skimmed.
Category:Gases