jsc2021e042554 (8/31/2021) --- Ground reference models of 3D-Printed items (shells and beads as granular filling material) as produced by the Additive Manufacturing Facility (AMF). The Granular Damping (ESA-EPO-Granular Damping) investigation studies the dynamics of granular matter (e.g. sand, corn, snow, rocks, dust or similar). Granular matter sediments on Earth, but can form a gas-like state of matter in space. Image courtesy of MadeInSpace.