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Dielectric and hardness measurements of planetary analog rocks in support of in-situ subsurface sampling

ElShafie, Ahmed and Heggy, Essam (2013) Dielectric and hardness measurements of planetary analog rocks in support of in-situ subsurface sampling. Planetary and Space Science, 86 . pp. 150-154. ISSN 0032-0633. doi:10.1016/j.pss.2013.02.003.

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Accurate assessment of the subsurface mechanical characteristics and how they correlate with dielectric properties is crucial to optimize future drilling and sampling investigations on planetary bodies. For 12 different types of basaltic rocks with different hardnesses, we use capacitive cells to measure the real part of the dielectric constant over the frequency range 100–1000 MHz, and a Schmidt hammer hardness tester to measure the hardness using a scale of 10–100. Our measurements suggest that the real part of the dielectric constant and rock hardness are linearly correlated. Additionally, sample hardness was linearly correlated to density. For a density ranging from 0.82 to 3.05 g/cm^3, the real part of the dielectric constant ε′ and rebound hardness values R ranged from ε′=1.8–7.6 and R=14.16–68 for the different basalt samples. Hence, high dielectric constants imply a high rock hardness value and vice versa. We concluded that for volcanic surfaces that are analogous to the Martian surface as well as other planetary surfaces, there is an inverse correlation between drilling penetration rate based on the rotary-percussive drill method and the dielectric constant. Dielectric inversion from planetary radar probing experiments proposed herein is a crucial method to locate regions with lowest hardness and hence highest drilling penetration rate in desiccated volcanic planetary subsurfaces. The use of these cross-correlation measurements can optimize future drilling experiments and ensure that they reach their targets of opportunities, minimize losses in drilling performance, or the unnecessary use of power that will be needed for the continuity of the investigation.

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Additional Information:© 2013 Elsevier. Received 7 June 2012. Received in revised form 8 November 2012. Accepted 12 February 2013. Available online 26 March 2013. The authors would like to thank Dr. Valerie Ciarletti from LATMOS, France and Dr. Stephen Clifford from the Lunar and Planetary Institute for their helpful discussion to improve this work. The NASA Planetary Geology and Geophysics Program supported this work under Grants NNXZ08AKA2G and NNG05GL11G. Additional support for PhD graduate student ElShafie was provided by the Arkansas Center for Space and Planetary Sciences, University of Arkansas and the Keck Institute for Space Studies. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a Contract with the National Aeronautics and Space Administration.
Group:Keck Institute for Space Studies
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Arkansas Center for Space and Planetary SciencesUNSPECIFIED
Keck Institute for Space Studies (KISS)UNSPECIFIED
Record Number:CaltechAUTHORS:20160304-150043792
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Official Citation:Ahmed ElShafie, Essam Heggy, Dielectric and hardness measurements of planetary analog rocks in support of in-situ subsurface sampling, Planetary and Space Science, Volume 86, 15 September 2013, Pages 150-154, ISSN 0032-0633, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65082
Deposited By: Colette Connor
Deposited On:04 Mar 2016 23:28
Last Modified:10 Nov 2021 23:39

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