THE EMERGENCE OF OXYGEN AND THE EVOLUTION OF PLANETARY INTERIORS ARE RECORDED IN THE REDOX STATES OF MULTIVALENT ELEMENTS (FE TI MN CR V AND EU) THAT ARE LOCKED IN ROCKS AND THE GLASSES AND MINERALS THAT CONSTITUTE THEM ON PLANETARY SURFACES. AS RECORDERS OF FORMATION CONDITIONS GLASSES AND AMORPHOUS MATERIALS COMPRISE MAJOR CONSTITUENTS OF PLANETARY MATERIALS ON BODIES WHERE MAGMATISM AND/OR IMPACT PROCESSES OCCUR. GLASS IS COMMON IN STONY METEORITES (BOTH ACHONDRITES AND CHONDRITES) AND LUNAR SAMPLES AND IS LIKELY TO BE PRESENT IN SAMPLES RETURNED FROM ASTEROIDS AND PLANETARY SURFACES SUCH AS BENNU (TARGET OF OSIRIS-REX) AND MARS. ROBUST LABORATORY ANALYSES OF MULTIVALENT ELEMENT REDOX STATES IN GLASSES FROM METEORITES AND RETURNED EXTRATERRESTRIAL MATERIALS ARE THUS ESSENTIAL TO FACILITATE UNDERSTANDING OF THE ROLE OF OXYGEN IN SOLAR SYSTEM PROCESSES. HOWEVER INTERPRETABLE MEASUREMENTS OF REDOX STATES AT SUB-NM AND PM SCALES STILL PRESENT FORMIDABLE ANALYTICAL CHALLENGES DUE TO THE LACK OF SUITABLE CALIBRATION SAMPLES. OUR GROUP HAS ALREADY DEVELOPED AN INTERNATIONALLY-USED SET OF CALIBRATION SAMPLES/SOFTWARE FOR X-RAY ABSORPTION SPECTROSCOPY (XAS) MEASUREMENTS OF FE REDOX STATES IN GARNETS AND AMPHIBOLES AS WELL AS IN A SELECT RANGE OF TERRESTRIALLY-RELEVANT SILICATE GLASS COMPOSITIONS. THIS PROPOSAL SEEKS TO BROADEN OUR GLASS CALIBRATION TO INCLUDE OTHER TRANSITION METALS (TI MN CR V AND EU) AND COVER THE REDUCED OXYGEN FUGACITIES NEEDED TO REPRESENT THE DIVERSITY OF SOLAR SYSTEM MATERIALS. SUCH DEVELOPMENT OF THE CAPABILITY TO MEASURE IN SITU REDOX STATES AT ATOMIC AND NEAR-ATOMIC LEVELS IN GLASSES HAS THE POTENTIAL TO MAKE DRAMATIC ADVANCES IN THE STUDY OF SOLAR SYSTEM MATERIALS IN BOTH RETURNED SAMPLES AND METEORITES. THEREFORE THIS PROPOSAL SEEKS TO CREATE A BROAD SUITE OF GLASSES OF GEOLOGICAL RELEVANCE FOR USE AS STANDARDS IN XAS CALIBRATIONS FOR THE STUDY OF EXTRATERRESTRIAL GLASS SAMPLES. USING SYNTHESIZED SAMPLES EQUILIBRATED OVER A RANGE OF OXYGEN FUGACITIES REPRESENTING THOSE FOUND IN OUR SOLAR SYSTEM WE WILL GENERATE XAS CALIBRATION DATA FOR REDOX CALIBRATIONS OF FE TI MN CR V AND EU IN GLASSES THAT ARE DIRECTLY REPRESENTATIVE OF OBSERVED METEORITIC AND PLANETARY COMPOSITIONS. WE WILL MAKE THESE ALIBRATIONS AVAILABLE TO THE PLANETARY MATERIALS AND BROADER SCIENCE COMMUNITIES VIA DISTRIBUTION DIRECTLY TO ALL INTERNATIONAL SYNCHROTRON FACILITIES WITH SPECTRAL DATA POSTED ON THE PDS GEOSCIENCES SPECTRAL LIBRARY. THE TASKS ARE AS FOLLOWS: 1) SYNTHESIZE GLASSES OVER A WIDE RANGE OF GEOLOGICALLY-RELEVANT CHEMICAL BULK COMPOSITIONS AT SEVERAL FO2 S USING A RANGE OF NATURALLYOCCURRING ABUNDANCES FOR FE AND DOPING OF OTHER MULTIVALENT SPECIES INCLUDING V TI EU MN AND CR. 2) CHARACTERIZE THE REDOX CONTENT OF EACH GLASS RELATIVE TO COMPOSITION AND FO2 USING M SSBAUER FOR FE AND ION MICROPROBE FOR EU AND XAS TECHNIQUES FOR FE V TI EU MN AND CR. 3) USE THOSE DATA TO BUILD A STATISTICAL MODEL FOR MEASURING REDOX RATIOS FOR EU AND FE (WHERE WE HAVE INDEPENDENT MEASUREMENTS) AND DIRECTLY PREDICTING OXYGEN FUGACITY FOR EACH OF THESE CATIONS ACROSS OUR BROAD COMPOSITIONAL RANGE USING SOPHISTICATED MULTIVARIATE ANALYSIS TECHNIQUES. THIS WORK IS HIGHLY RELEVANT TO NASA S PDART PROGRAM AS IT WILL GENERATE VALUABLE NEW REFERENCE INFORMATION (LABORATORY SAMPLES AND XAS MEASUREMENTS) AND DEVELOP HIGH-ORDER SOFTWARE FOR PREDICTING VALENCE STATE. THE LATTER TOOLS WILL ENABLE USE OF THE XAS TECHNIQUE TO PRODUCE REDOX STATE MEASUREMENTS OF FE TI MN CR V AND EU WITH KNOWN ACCURACY FOR A WIDE RANGE OF EXTRATERRESTRIALLY-RELEVANT GLASS COMPOSITIONS. OUR DELIVERABLES WILL ENSURE THAT MICROANALYSIS OF REDOX STATES CAN BE USED BROADLY BY THE PLANETARY COMMUNITY TO MAXIMIZE SCIENCE RETURN FROM PRECIOUS EXTRATERRESTRIAL SAMPLES.