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Properties of simulated comet mantleThe properties of freeze-dried dilute dispersions of dust in water ice are of considerable interest in studies of comet nucleus mantles. The formation of a rind residue produced by the sublimation of water ice containing various amounts of fine clay particles may be an important process. A simulation of the development of the dry dust rind on the surface of comets is presented. This rind is the result of preferential ice sublimation. The development and disruption of this rind and its subsequent levitation by water vapor flow is studied. The most interesting rind simulant is produced by dispersing 0.1 micron particles of montmorillonite in water in concentrations of 10%, 1%, and 0.1%. These dispersions are then sprayed into liquid nitrogen in the form of 100 micron droplets. The frozen droplets are then freeze-dried in a vacuum which prevents the ice temperature from rising above -30 C. Sublimation of the nitrogen and the water produced dry rinds. The most striking result was the development of large cohesive matrices of individual clay particles, and in some cases a continuous cohesive crust. Scanning electron microscope (SEM) observations reveal that the material formed by freeze-drying the 0.1% dispersion does not retain the original spherical shape of the sprayed 100 micron droplets; instead it consists of a continuous filamentary network, as shown in the SEM stereo micrographs.
Document ID
19840015384
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Fanale, F. P.
(Hawaii Univ. Pasadena, CA, United States)
Saunders, S.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Banerdt, B.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Stephens, J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Laue, E.
(Jet Propulsion Lab., California Inst. of Tech.)
Sutton, S.
(Michingan Univ.)
Date Acquired
August 12, 2013
Publication Date
April 1, 1984
Publication Information
Publication: NASA. Washington Repts. of Planetary Geol. Program
Subject Category
Lunar And Planetary Exploration
Accession Number
84N23452
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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