Microgravity Granular Material Research Facility for ISS

Under a NASA SBIR Phase 1 project, TransAstra Corporation in collaboration with the Colorado School of Mines and Grainflow Dynamics, Inc. is developing and testing a prototype micro-g granular material research (MGMR) facility for the International Space Station (ISS). The proposed facility will provide a unique opportunity to gain understanding of the fundamental physical behavior of granular solids in microgravity over a range of solids fractions that are unobtainable terrestrially due to gravitationally induced settling. Although it is known that behavior of granular materials under microgravity is strongly influenced by cohesion among particles (e.g., aggregation of particles can result in the formation of gel-like structures which grow to fill available volumes) details of these processes are not well understood. Applications of this work include fundamental science associated with planetary accretion, space habitat air filtration system design, control of particles for microgravity additive manufacturing, and process design for the fabrication of radiation shields from regolith in microgravity. The ISS facility will be suitable for studying steady or variable gas-solid flows over a nearly 2-order of magnitude range in particle size and 4-orders of magnitude in solids-fraction at gas pressures ranging from atmospheric to near-vacuum and flow velocities from on the order of 10 m/s to stationary. The Phase 1 ground demonstration unit uses low-density particles and gas fluidization to mimic the micro-gravity transport of granular solids through the ‘micro-gravity’ granular-solids test section, and employs gravity-independent centrifugal settling to provide gas-solid separation in a manner analogous to the proposed ISS facility. This paper describes the mid-term status of the SBIR project.