Astronauts may be able to make cement using their own pee
Future astronauts could make lunar buildings out of moon dust and pee. That’s the suggestion of chemist Anna-Lena Kjøniksen and her colleagues, who made a cement from urea — a major component of urine — and faux lunar soil. When humans take up long-term residence on other planets or the moon, they will need to pack light, in part because shipping materials from Earth is expensive. NASA has estimated that every pound of material sent into orbit around the Earth costs around $10,000. Tapping into local resources could keep costs down. Researchers have suggested using lunar soil to make concrete or cement to 3-D print dwellings for astronauts (SN: 2/21/13). But most cement recipes require a lot of water, which is scarce on the moon and awfully heavy to blast into space (SN: 4/15/19). On Earth, adding a chemical called a superplasticizer to a cement mix reduces the amount of water needed by keeping a drier mix from getting too crumbly, while leaving it flexible enough...