Water, Not Gold: Fueling Space Missions with In-Situ Resources

Water is argued to be the most valuable space resource because, when split into hydrogen and oxygen, it becomes rocket propellant that can be produced in orbit from solar energy. A propellant depot in orbit would sell to outbound missions (Moon, Mars, and beyond) rather than Earth, since launching propellant from Earth is costly. The near-term path focuses on lunar water ice and Artemis tests, while asteroid mining remains uncertain. The key test is whether space-made propellant can beat Earth-launched propellant; until then water is valuable mostly in theory. Past ventures into space mining failed to mature, and the market for in-space refueling remains unproven.