ISRU can involve utilization of regolith directly as a building material, its constituent minerals as sources for oxygen or metals, or of frozen volatiles contained in it. Whether the process is melting via concentrated solar radiation for additive manufacturing, heating in a rotating fluidized bed for volatile extraction, or electrostatic beneficiation of tribo-charged mineral particles to separate ilmenite for oxygen extraction utilizing hydrogen reduction, each process works best for a particular size range of particles, and may not function at all for particle sizes very far outside of the optimal range. Gravity-independent methods to reliably size-sort regolith into multiple conveying lines will be developed and demonstrated. This project will also demonstrate improved methods for low-gravity, conveying, storage and delivery of regolith in flow-rate controlled streams that can be movable, and can function at gravity levels as low as zero. No gas-solid separation steps are required for the proposed all-mechanical size separation system, and the basic multiple size-separation unit has only one major moving part to create all preselected size ranges. The system will function independent of gravity level. During Phase-2 novel movable (articulated) conveying lines that can deliver the sorted feedstock anywhere within a finite 3D-volume will be developed/demonstrated. The flexibility of having adjustable end points could facilitate utilization of such regolith feedstock streams in direct additive manufacturing of regolith based structures, or they could be directed to temporary buffer storage vessels for subsequent continuous or batch delivery to processing equipment.
A robust efficient system to size-separate regolith will benefit most ISRU operations. The proposed all-mechanical system is appropriate for the broadest range of potential environments from planetary surfaces to small airless bodies. Beneficiation methods, such as tribo-charging and electrostatic separation to increase concentrations of certain minerals, function best over restricted particle-size ranges. Size-segregated feedstock can improve effectiveness of such processes, as well and many other proposed regolith ISRU processing systems.
This project will reduce-to-practice a new feeder for ‘flexible screw conveyors’.which can substantially broaden operating conditions, and may lead to licensing agreements with companies like Flexicon or Hapman. Also, metal Laser Powder Bed Fusion (LPBF) additive manufacturing sieves all recycled powder. This simple approach can be more robust than the sieves being developed in the AM community.