Through student participation in NASA flight tests, we have demonstrated the feasibility of forming complex and useful shapes in microgravity from pulverized material using sound waves, and correlated the shapes to mathematical predictions. The demonstrated potential is exciting, but the concept requires scientific studies before engineering design tools can be developed. The basics of the technology, the results to date, and the outstanding issues are summarized. The idea of Acoustic Shaping is simple.
Sound waves exert some force on particles.
With gravity removed, this force is enough to move the particles. In a reverberating container, solid particles are moved towards the nodes of the sound field. By driving different natural frequencies, one can generate nodal planes of various shapes. If the particles can be held in place long enough, either phase change or chemical reactions can be used to form hard panels, just as if they were formed over solid molds. Bulky pieces needed for space stations and habitats, could be built using low grade materials such as lunar dust or regolith, without heavy machine tools, dies and molds from earth.