<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-19T19:49:31Z</responseDate><request verb="GetRecord" identifier="oai:dspace.mit.edu:1721.1/107110" metadataPrefix="dim">https://dspace.mit.edu/server/oai/request</request><GetRecord><record><header><identifier>oai:dspace.mit.edu:1721.1/107110</identifier><datestamp>2022-01-13T07:53:59Z</datestamp><setSpec>com_1721.1_7582</setSpec><setSpec>com_1721.1_7581</setSpec><setSpec>col_1721.1_131023</setSpec></header><metadata><dim:dim xmlns:dim="http://www.dspace.org/xmlns/dspace/dim" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.dspace.org/xmlns/dspace/dim http://www.dspace.org/schema/dim.xsd">
   <dim:field mdschema="dc" element="contributor" qualifier="advisor" lang="en_US">Sara Seager.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="author" lang="en_US">Atkinson, Jared William Graham</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="other" lang="en_US">Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="department">Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="accessioned">2017-02-22T19:03:59Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="available">2017-02-22T19:03:59Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="copyright" lang="en_US">2016</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="issued" lang="en_US">2016</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="uri">http://hdl.handle.net/1721.1/107110</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="oclc" lang="en_US">971495515</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Thesis: S.M. in Planetary Sciences, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Cataloged from PDF version of thesis.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Includes bibliographical references (pages 65-70).</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">Sample retrieval from extraterrestrial bodies and in situ resource utilization (ISRU) activities have been identified as some of the most important scientific endeavors of the coming decade. With the failure of Rosetta's Philae lander to penetrate the surface of comet 67P and obtain a sample due to the high compressive strength of the surface, it is becoming obvious that knowledge of the mechanical properties of materials that might be encountered in such environments and under such conditions is critical to future mission success. Two comet/asteroid analogs (Indiana limestone and Bishop tuff), selected based on their contrasting mechanical properties and porosities, were tested under constant displacement to failure (in most cases) at extraterrestrial conditions of cryogenic temperatures (295 K down to 77 K) and light confining pressures (1 to 5 MPa). The compressive strength of both materials was determined under varied conditions of saturation, from oven-dried (~0% water content) to fully saturated, and both brittle and ductile behavior was observed. The saturated limestone increased in strength from -30 MPa (at 295 K) to >200 MPa (at 77 K), while the Bishop tuff increased in strength from 13 MPa at 295 K to 165 MPa at 150 K. Additional experiments demonstrated that thermal cycling reduces the compressive strength of limestone, while an increase in confining pressure from 5 MPa to 30 MPa at 200 K significantly increases the strength (from 62 MPa to 85 MPa respectively) of saturated tuff. The results of this study will be useful to future sample retrieval missions or ISRU maneuvers. The large increase in compressive strength of these saturated materials at cryogenic temperatures means that future missions will need to prepare technology that has the energetic and mechanical capability to penetrate very hard substrates as they are likely to encounter.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="statementofresponsibility" lang="en_US">by Jared William Graham Atkinson.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="degree" lang="en_US">S.M. in Planetary Sciences</dim:field>
   <dim:field mdschema="dc" element="format" qualifier="extent" lang="en_US">70 pages</dim:field>
   <dim:field mdschema="dc" element="language" qualifier="iso" lang="en_US">eng</dim:field>
   <dim:field mdschema="dc" element="publisher" lang="en_US">Massachusetts Institute of Technology</dim:field>
   <dim:field mdschema="dc" element="rights" lang="en_US">MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.</dim:field>
   <dim:field mdschema="dc" element="rights" qualifier="uri" lang="en_US">http://dspace.mit.edu/handle/1721.1/7582</dim:field>
   <dim:field mdschema="dc" element="subject" lang="en_US">Earth, Atmospheric, and Planetary Sciences.</dim:field>
   <dim:field mdschema="dc" element="title" lang="en_US">Cryogenic deformation of two comet and asteroid analogs under varying conditions of saturation</dim:field>
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   	&lt;Title>Cryogenic deformation of two comet and asteroid analogs under varying conditions of saturation&lt;/Title>
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   	&lt;PublicationDate>2016&lt;/PublicationDate>
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        	&lt;DisplayName>Atkinson, Jared William Graham&lt;/DisplayName>
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    &lt;Keyword>Earth, Atmospheric, and Planetary Sciences.&lt;/Keyword>
   	&lt;Abstract>Sample retrieval from extraterrestrial bodies and in situ resource utilization (ISRU) activities have been identified as some of the most important scientific endeavors of the coming decade. With the failure of Rosetta&amp;apos;s Philae lander to penetrate the surface of comet 67P and obtain a sample due to the high compressive strength of the surface, it is becoming obvious that knowledge of the mechanical properties of materials that might be encountered in such environments and under such conditions is critical to future mission success. Two comet/asteroid analogs (Indiana limestone and Bishop tuff), selected based on their contrasting mechanical properties and porosities, were tested under constant displacement to failure (in most cases) at extraterrestrial conditions of cryogenic temperatures (295 K down to 77 K) and light confining pressures (1 to 5 MPa). The compressive strength of both materials was determined under varied conditions of saturation, from oven-dried (~0% water content) to fully saturated, and both brittle and ductile behavior was observed. The saturated limestone increased in strength from -30 MPa (at 295 K) to &amp;gt;200 MPa (at 77 K), while the Bishop tuff increased in strength from 13 MPa at 295 K to 165 MPa at 150 K. Additional experiments demonstrated that thermal cycling reduces the compressive strength of limestone, while an increase in confining pressure from 5 MPa to 30 MPa at 200 K significantly increases the strength (from 62 MPa to 85 MPa respectively) of saturated tuff. The results of this study will be useful to future sample retrieval missions or ISRU maneuvers. The large increase in compressive strength of these saturated materials at cryogenic temperatures means that future missions will need to prepare technology that has the energetic and mechanical capability to penetrate very hard substrates as they are likely to encounter.&lt;/Abstract>
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