In situ resource utilization
In space exploration, in situ resource utilization (ISRU) is the practice of collection, processing, storing and use of materials found or manufactured on other astronomical objects (the Moon, Mars, asteroids, etc.) that replace materials that would otherwise be brought from Earth. ISRU could provide materials for life support, propellants, construction materials, and energy to a spacecraft payloads or space exploration crews.
Source: Wikipedia — In situ resource utilization (CC BY-SA 4.0)