17 Materials production

The topic of materials is both a category of technical competencies – knowing how to select and use specific materials – and a major area of human activity. Here we focus on the latter aspect, thinking about the large-scale dedication of human effort to gathering and refining raw materials and then to distributing the resulting products to manufacturers and individual users. In the mining industry, finding and extracting the ores from which we derive metals and other useful materials is rich in applications of physics. As obvious deposits become depleted, we need more sophisticated methods for locating ore deposits. Then there are prospects for improving the safety and efficiency of extraction processes while also lessening the adverse environmental impacts. Extraction of materials from the oceans is likely to be open to much more development. Forestry is a completely different realm of raw material production, potentially capable of being a renewable source of materials. Agriculture produces materials for textiles: while renewable in many ways, current practices consume large amounts of energy and water so there is much opportunity for improvement. Thinking more broadly, how can the realm of renewable material production using living organisms be extended to include plastics, oils, solvents, and even refined inorganic minerals? Physics also serves the technical issues associated with bulk storage and transport of raw materials: how do we effectively collect and move thousands of tons of matter in various forms? Once materials arrive at refining plants, large scale processes exchange matter and energy to bring about the necessary changes: there is a great contrast in scales, in which molecular-level changes are carried out with quantities of thousands of tons. It is intriguing to think about ways to bring down the scale of production so that sophisticated materials refinement can be provided at distributed locations, perhaps both in urban centers that mix in recycled stock and in remote villages that are close to specific feedstock. How might such medium-scale processes be conducted very far away on the surface of the moon or Mars or asteroids?