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An Exponential Luminous Efficiency Model for Hypervelocity Impact into RegolithThe flash of thermal radiation produced as part of the impact-crater forming process can be used to determine the energy of the impact if the luminous efficiency is known. From this energy the mass and, ultimately, the mass flux of similar impactors can be deduced. The luminous efficiency, eta, is a unique function of velocity with an extremely large variation in the laboratory range of under 6 km/s but a necessarily small variation with velocity in the meteoric range of 20 to 70 km/s. Impacts into granular or powdery regolith, such as that on the moon, differ from impacts into solid materials in that the energy is deposited via a serial impact process which affects the rate of deposition of internal (thermal) energy. An exponential model of the process is developed which differs from the usual polynomial models of crater formation. The model is valid for the early time portion of the process and focuses on the deposition of internal energy into the regolith. The model is successfully compared with experimental luminous efficiency data from both laboratory impacts and from lunar impact observations. Further work is proposed to clarify the effects of mass and density upon the luminous efficiency scaling factors. Keywords hypervelocity impact impact flash luminous efficiency lunar impact meteoroid 1
Document ID
20110016594
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Swift, W. R.
(Jacobs Engineering Group, Inc. Huntsville, AL, United States)
Moser, D. E.
(Dynetics, Inc. Huntsville, AL, United States)
Suggs, R. M.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Cooke, W. J.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 25, 2013
Publication Date
July 1, 2011
Publication Information
Publication: Meteoroids: The Smallest Solar System Bodies
Subject Category
Space Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.
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