The sustainable human presence in space beyond low earth orbit is contingent on the effective use of local resources, what has since been termed in-situ resource utilization (ISRU). Metal extraction from lunar and Martian regolith has become a significant area of interest for the ISRU community, enabling in-situ production of metallic equipment, spares, and construction materials for various mission scenarios. However, the extraction of metals from the astronaut waste stream has yet to be thoroughly investigated. A thermochemical Trash-to-Gas (TtG) process was utilized to isolate pure aluminum (Al 1235) from multilayer astronaut waste food packaging, one of the most abundant crew waste items expected for future exploration missions. The extracted aluminum was post-processed to enable compatibility with the bound metal deposition (BMD) additive manufacturing process. The aluminum material was cleaned, converted into a powder, and incorporated into an aluminum paste mixture to enable effective extrusion of the material. The particle size distribution, morphology, oxygen content, and elemental composition of the extracted aluminum powder as compared with commercial-off-the-shelf (COTS) Al 1235 powder is reported. Tensile bars derived from the TtG Al 1235 powder and COTS Al 1235 powder were produced via bound metal deposition and the resultant mechanical properties of the aluminum feedstocks are compared (ultimate tensile strength, density). A discussion as to the metallic paste formulation and bound metal deposition parameter optimization is also described. The results described herein demonstrate an end-to-end waste metallic reuse process which may garner considerable metal recovery and recycling that would otherwise be disposed of on the surface of the Moon or Mars.
Pitts et al. (Sun,) studied this question.