Scientists left 'Moon cement' outside the ISS for six months; it came back up to 35% stronger

Scientists exposed 'Moon cement' made from lunar and Martian regolith simulants outside the ISS for six months, facing vacuum, radiation, and temperature variations.

One formulation of the geopolymer returned with compressive strength 35% higher than Earth-based controls.

The material showed no degradation after six months in space, supporting plans for in-situ resource utilization on the Moon.

The cement is a geopolymer formed by reacting aluminosilicate-rich simulants with an alkaline solution, avoiding traditional Portland cement.

Results were published in Advances in Space Research and detailed by the University of Delaware, based on NASA's MISSE-20 mission.