Microgravity particle research on the space station: The gas-grain simulation facility

Fogleman, Guy; Huntington, J. L.; Carle, G. C.; Nuth, J. A.

doi:10.1016/0273-1177(89)90369-4

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…Irradiation of floating particles with solar ultraviolet radiation and cosmic rays is quite difficult in the presence of gravity. Studies on the gas-grain simulator (McKay, et al, 1986, Fogleman, et al, 1989 imply theoretical considerations on the size range of particles that require microgravity to reveal new physics and chemistry.…”

Section: Experimental Objectives and Scientific Requirementsmentioning

confidence: 99%

A Conceptual Design for Cosmo-biology Experiments in Earth's Orbit.

et al. 1998

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A conceptual design was developed for a cosmo-biology experiment. It is intended to expose simulated interstellar ice materials deposited on dust grains to the space environment. The experimental system consists of a cryogenic system to keep solidified gas sample, and an optical device to select and amplify the ultraviolet part of the solar light for irradiation. By this approach, the long lasting chemical evolution of icy species could be examined in a much shorter time of exposure by amplification of light intensity. The removal of light at longer wavelength, which is ineffective to induce photochemical reactions, reduces the heat load to the cryogenic system that holds solidified reactants including CO as a constituent species of interstellar materials. Other major hardware components were also defined in order to achieve the scientific objectives of this experiment. Those are a cold trap maintained at liquid nitrogen temperature to prevent the contamination of the sample during the exposure, a mechanism to exchange multiple samples, and a system to perform bake-out of the sample exposure chamber. This experiment system is proposed as a candidate payload implemented on the exposed facility of Japanese Experiment Module on International Space Station.

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Section: Experimental Objectives and Scientific Requirementsmentioning

confidence: 99%

A Conceptual Design for Cosmo-biology Experiments in Earth's Orbit.

et al. 1998

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“…The GGSF will provide the necessary low-gravity environment for smallparticle experimentation (Fogleman et al, 1988a and1988b). It will consist of an adaptable 4 to 10 liter experiment chamber supported by subsystems providing environmental control, measurement equipment, levitation capability, and energy sources.…”

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confidence: 99%

On performing exobiology experiments on an earth-orbital platform with the gas-grain simulation facility

Huntington

Fogleman

1989

Origins Life Evol Biosphere

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Processes involving small particles (micron-sized) are important to understanding the origin and nature of interplanetary dust, comets, protoplanetary particles, Titan's organic aerosol and solar system bodies in general. The large scale behavior of astrophysical systems is often determined by small-particle processes such as nucleation of particles from a gas, accretion of gaseous species onto grains, particle coagulation, and low-velocity collisions between grains. Laboratory studies of these processes would contribute toward important exobiological goals such as determining how the physical and chemical properties of the biogenic elements influenced solar system formation, chemical evolution and the origin of life (Klein et al., 1989). One example relevant to chemical evolution concerns the chemical reactions between gas and dust which have been hypothesized to occur in interstellar clouds and the solar nebula to account for the organic matter observed in clouds, meteorites, comets and interplanetary dust. In one possible mechanism for these reactions, dust provides an active surface for catalysis of sorbed gas ~nolecules (e.g. H2, CO, CO2, and NH3), converting them into organic compounds. However, this cannot explain all characteristics of the observed material. Laboratory simulations of gas-dust interactions in a realistic environment (i.e., low gas pressure and density of dust) could yield much insight into the origins and nature of the observed organic matter. Other processes that merit laboratory study are the photoirradiation of icy dust-mantles by starlight, thermal evolution of interstellar cot)densates in the solar nebula, and the possible enhancement of accretion and growth of planetesimals by nebular dust that has icy mantles or mantles containing organic material. Yet, realistic simulations of these and other small-particle processes occurring in cosmic environments are difficult if not impossible to perform in laboratories on Earth because of gravitational settling.Earth's gravity causes aerosols and small particles to quickly settle out of experiment chambers. High settling rates prohibit performance of experiments that are long in duration, involve three-dimensional low-velocity particle collisions, or attempt to grow large particles by coagulation. Furthermore, gravitationally-driven turbulence makes a homogeneous, convection-free experiment environment (important to crystal growth) impossible to obtain. Many problems encountered in small-particle experimentation on Earth can be overcome in the environment of an Earth-orbital platform such as Space Station Freedom. In the laboratory region of Freedom, gravitational acceleration will be greatly reduced, yet tidal effects will cause a residual 493

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