Metal Foam Casting: Earth vs Microgravity

Space manufacturing is not only about 3D printing — casting metal foam is one of the clearest cases where removing gravity changes the physics of a material outright. This simulator nucleates gas bubbles inside a molten-metal mold, moves each one by the same Stokes buoyancy law that governs real foundries, lets nearby bubbles coalesce, and freezes the structure in place as a solidification front climbs from the mold floor. Drag the gravity slider from Earth's 1 g down to ISS-level microgravity and watch the foam go from coarse, graded and full of escaped bubbles to fine, uniform and closed-cell — exactly the outcome that has driven real orbital foam-casting experiments.