aluminum - sswelm/KSP-Interstellar-Extended GitHub Wiki
Aluminum is used along with oxidizer as the fuel source for HA 1 Aluminum Hybrid Rocket.
It is obtained by the electrolysis of Alumina, which is currently only located on Mun, Tylo, and Ike. It must be extracted from the crust via the ISRU Refinery, however electrolysis can be performed by both the in-line refinery and ISRU. Alumina electrolysis outputs the correct ratio of both the Aluminum and Oxidizer needed to fuel the Aluminum-Hybrid Rocket.