Living Martian building materials

Engineered microbes (yeast) can be combined with Martian regolith and simple biomatrices to 3D‑print living, freeze‑hardened construction elements that scale to human‑sized habitats in low gravity. The technique trades energy‑intensive melting/sintering for biological binding and freeze‑drying, promising a lower‑mass, recyclable construction supply for Mars missions. — If feasible, this shifts how we plan Mars missions, creating policy questions about planetary protection, biological containment, commercial off‑world manufacturing, and the ethical use of engineered organisms in other worlds.