BEHAVIOR OF PARTICULATE MATERIALS AT VERY LOW PRESSURES

Three separate sets of cyclic compression and extension experiments on loose and dense specimens of cohesionless assemblies of subangular quartz particles were conducted under displacement control at very low effective pressure levels. The first two sets were conducted under drained conditions on separate flights of the NASA Space Shuttle (STS-79, 1996; and STS89, 1998) under microgravity conditions, and the last set was recently conducted on Columbia (STS-107) in January, 2003. The Columbia experiments were designed both to verify earlier data as well as to expand into new areas. Large portions of the STS-107 data were collected via telemetry during flight, although the on-board stored data records, the specimens and experiment hardware were lost. Overall experiment technique, observations and data will be presented for all sets of experiments, with a focus placed on the planned and achieved goals of the Columbia experiments.