Start Date

4-1988 8:00 AM

Description

A wide variety of experiments significant to Exobiology, Planetary Science, Astrophysics, Atmospheric Science, and basic Chemistry and Physics involves the physical interactions of small particles (micrometer to centimeter in size). In many astro-geophysical systems (atmospheric clouds, interstellar clouds, planetary rings, Titan's organic aerosols, Martian dust storms, lightning, etc.), processes involving small particles determine the overall behavior of the system. Condensation of particles from a gas, aggregation of small particles into larger ones, low velocity collisions, and charge accumulation are a few of the processes that influence particles in these systems. Examples of particles undergoing these processes include interstellar grains, protoplanetary particles, atmospheric aerosols, combustion products, and abiotic organic polymers.

Although processes of the type described above span a wide range of disciplines, the study of these processes places common fundamental constraints on particle handling. Two common constraints are the need for long time periods during which the particles must be suspended and low relative velocities between particles. Experiments involving small particles generally require material be suspended for periods substantially longer than are practical in Earth's 1 g gravitational field. However, one can investigate these processes with a general-purpose particle research facility (in particular, with the proposed Gas-Grain Simulation Facility) on the Space Station 1 '3 . Because of the very low gravitational acceleration (microgravity) in the Earth orbital environment, many experiments deemed impractical or impossible to perform on Earth will become feasible. Such experiments are those in which gravity either interferes directly with the phenomenon under study (e.g., gravitational convection masks diffusional processes) or in which gravity precludes the establishment of the proper experimental conditions (e.g., in 1 g, gravity accelerates test objects to unacceptable velocities).

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Apr 1st, 8:00 AM

Space Station Gas-Grain Simulation Facility: Microgravity Particle Research

A wide variety of experiments significant to Exobiology, Planetary Science, Astrophysics, Atmospheric Science, and basic Chemistry and Physics involves the physical interactions of small particles (micrometer to centimeter in size). In many astro-geophysical systems (atmospheric clouds, interstellar clouds, planetary rings, Titan's organic aerosols, Martian dust storms, lightning, etc.), processes involving small particles determine the overall behavior of the system. Condensation of particles from a gas, aggregation of small particles into larger ones, low velocity collisions, and charge accumulation are a few of the processes that influence particles in these systems. Examples of particles undergoing these processes include interstellar grains, protoplanetary particles, atmospheric aerosols, combustion products, and abiotic organic polymers.

Although processes of the type described above span a wide range of disciplines, the study of these processes places common fundamental constraints on particle handling. Two common constraints are the need for long time periods during which the particles must be suspended and low relative velocities between particles. Experiments involving small particles generally require material be suspended for periods substantially longer than are practical in Earth's 1 g gravitational field. However, one can investigate these processes with a general-purpose particle research facility (in particular, with the proposed Gas-Grain Simulation Facility) on the Space Station 1 '3 . Because of the very low gravitational acceleration (microgravity) in the Earth orbital environment, many experiments deemed impractical or impossible to perform on Earth will become feasible. Such experiments are those in which gravity either interferes directly with the phenomenon under study (e.g., gravitational convection masks diffusional processes) or in which gravity precludes the establishment of the proper experimental conditions (e.g., in 1 g, gravity accelerates test objects to unacceptable velocities).

 

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