<?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1K00.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>
<Product_Collection xmlns="http://pds.nasa.gov/pds4/pds/v1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://pds.nasa.gov/pds4/pds/v1 https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1K00.xsd">
    <Identification_Area>
        <logical_identifier>urn:nasa:pds:mer_apxs_composites_library:data</logical_identifier>
        <version_id>1.1</version_id>
        <title>MER APXS Composite Spectra Library</title>
        <information_model_version>1.20.0.0</information_model_version>
        <product_class>Product_Collection</product_class>
        <Citation_Information>
            <author_list>Knight, A. L.; VanBommel, S. J.; Gellert, R.</author_list>
            <publication_year>2024</publication_year>
            <doi>10.17189/fmmx-db70</doi>
            <description>
                This collection contains a library of target characteristics, metadata, composite spectra, and concentrations
                created from individual spectra acquired by the Alpha Particle X-ray Spectrometers on 
                Mars Exploration Rovers 1 and 2 (Opportunity and Spirit). 
            </description>
        </Citation_Information>
        <Modification_History>
            <Modification_Detail>
                <modification_date>2025-11-03</modification_date>
                <version_id>1.1</version_id>
                <description>Updated external references and investigation area name.</description>
            </Modification_Detail>
            <Modification_Detail>
                <modification_date>2024-06-06</modification_date>
                <version_id>1.0</version_id>
                <description>Initial version</description>
            </Modification_Detail>
        </Modification_History>
    </Identification_Area>
    <Context_Area>
        <Time_Coordinates>
            <start_date_time>2004-01-05Z</start_date_time>
            <stop_date_time>2018-06-10Z</stop_date_time>
        </Time_Coordinates>
        <Primary_Result_Summary>
            <purpose>Science</purpose>
            <processing_level>Calibrated</processing_level>
            <Science_Facets>
                <domain>Surface</domain>
                <discipline_name>Geosciences</discipline_name>
            </Science_Facets>
        </Primary_Result_Summary>
        <Investigation_Area>
            <name>Mars Exploration Rovers: Spirit and Opportunity</name>
            <type>Mission</type>
            <Internal_Reference>
                <lid_reference>urn:nasa:pds:context:investigation:mission.mars_exploration_rover</lid_reference>
                <reference_type>collection_to_investigation</reference_type>
            </Internal_Reference>
        </Investigation_Area>
        <Observing_System>
            <Observing_System_Component>
                <name>Mars Exploration Rover 1</name>
                <type>Host</type>
                <Internal_Reference>
                    <lid_reference>urn:nasa:pds:context:instrument_host:spacecraft.mer1</lid_reference>
                    <reference_type>is_instrument_host</reference_type>
                </Internal_Reference>
            </Observing_System_Component>
            <Observing_System_Component>
                <name>Alpha Particle X-ray Spectrometer</name>
                <type>Instrument</type>
                <Internal_Reference>
                    <lid_reference>urn:nasa:pds:context:instrument:apxs.mer1</lid_reference>
                    <reference_type>is_instrument</reference_type>
                </Internal_Reference>
            </Observing_System_Component>
        </Observing_System>
        <Observing_System>
            <Observing_System_Component>
                <name>Mars Exploration Rover 2</name>
                <type>Host</type>
                <Internal_Reference>
                    <lid_reference>urn:nasa:pds:context:instrument_host:spacecraft.mer2</lid_reference>
                    <reference_type>is_instrument_host</reference_type>
                </Internal_Reference>
            </Observing_System_Component>
            <Observing_System_Component>
                <name>Alpha Particle X-ray Spectrometer</name>
                <type>Instrument</type>
                <Internal_Reference>
                    <lid_reference>urn:nasa:pds:context:instrument:apxs.mer2</lid_reference>
                    <reference_type>is_instrument</reference_type>
                </Internal_Reference>
            </Observing_System_Component>
        </Observing_System>
        <Target_Identification>
            <name>Mars</name>
            <type>Planet</type>
            <Internal_Reference>
                <lid_reference>urn:nasa:pds:context:target:planet.mars</lid_reference>
                <reference_type>collection_to_target</reference_type>
            </Internal_Reference>
        </Target_Identification>
    </Context_Area>
    <Reference_List>
        <External_Reference>
            <doi>10.1029/2003JE002150</doi>
            <reference_text>
                Rieder, R., et al., The new Athena Alpha Particle X-Ray Spectrometer 
                (APXS) for the Mars Exploration Rovers, Journal of Geophysical Research, 2003.
            </reference_text>
        </External_Reference>
        <External_Reference>
            <doi>10.1029/2005JE002555</doi>
            <reference_text>
                Gellert, R., et al., Alpha Particle X-Ray Spectrometer (APXS): 
                Results from Gusev crater and calibration report, Journal of Geophysical Research, 2006.
            </reference_text>
        </External_Reference>
        <External_Reference>
            <doi>10.1029/2021JE006915</doi>
            <reference_text>
                Mittlefehldt, D. W., et al., Geology and geochemistry of Noachian bedrock and alteration events,
                Meridiani Planum, Mars: MER Opporunity observations, Journal of Geophysical Research: Planets, 2021.
            </reference_text>
        </External_Reference>
        <External_Reference>
            <doi>10.1029/2008JE003195</doi>
            <reference_text>
                Ming, D. W., et al., Geochemical properties of rocks and soils in Gusev Crater, Mars:
                Results of the Alpha Particle X-Ray Spectrometer from Cumberland Ridge to Home Plate, Journal of Geophysical Research, 2008.
            </reference_text>
        </External_Reference>
        <External_Reference>
            <doi>10.1029/2024JE008569</doi>
            <reference_text>
                Knight, A. L., VanBommel, S. J., Gellert, R., Berger, J. A., 
                Catalano, J. G., Gross, J., and Christian, J. R. (2025). 
                Gallium and germanium concentrations from the MER Alpha 
                Particle X-ray Spectrometers: Evidence of global trace element 
                enrichment. Journal of Geophysical Research: Planets, 130, 
                e2024JE008569.
            </reference_text>
        </External_Reference>
    </Reference_List>
  <Collection>
    <collection_type>Data</collection_type>
  </Collection>
  <File_Area_Inventory>
    <File>
      <file_name>collection_data_inventory.csv</file_name>
      <creation_date_time>2023-07-16</creation_date_time>
    </File>
    <Inventory>
      <offset unit="byte">0</offset>
      <parsing_standard_id>PDS DSV 1</parsing_standard_id>
      <records>5</records>
      <record_delimiter>Carriage-Return Line-Feed</record_delimiter>
      <field_delimiter>Comma</field_delimiter>
      <Record_Delimited>
        <fields>2</fields>
        <groups>0</groups>
        <Field_Delimited>
          <name>Member Status</name>
          <field_number>1</field_number>
          <data_type>ASCII_String</data_type>
          <maximum_field_length unit="byte">1</maximum_field_length>
          <description>
                        P indicates primary member of the collection
                        S indicates secondary member of the collection
                    </description>
        </Field_Delimited>
        <Field_Delimited>
          <name>LIDVID_LID</name>
          <field_number>2</field_number>
          <data_type>ASCII_LIDVID_LID</data_type>
          <maximum_field_length unit="byte">255</maximum_field_length>
          <description>
                        The LID or LIDVID of a product that is a member
                        of the collection.
                    </description>
        </Field_Delimited>
      </Record_Delimited>
      <reference_type>inventory_has_member_product</reference_type>
    </Inventory>
  </File_Area_Inventory>
</Product_Collection>