TO INCREASE THE SCIENTIFIC RETURN OF SAMPLE RETURN MISSIONS WE AIM TO MAXIMIZE THE INFORMATION GAINED FROM INDIVIDUAL MINERALS. ONE MINERAL SYSTEM THAT RECORDS A RANGE OF PRE- AND POST-ACCRETIONARY HISTORIES ARE THE FE-SULFIDES. THEY OCCUR IN A WIDE RANGE OF EXTRATERRESTRIAL MATERIALS AND ARE ATTRIBUTED TO FORMING THROUGH A RANGE OF PROCESSES IN THE EARLY SOLAR SYSTEM. SUCH PROCESSES INCLUDE CONDENSATION CRYSTALLIZATION/EXSOLUTION GAS-SOLID/LIQUID REACTION THERMAL METAMORPHISM AND AQUEOUS-PHASE PROCESSING. PREVIOUS WORK ON HAYABUSA SAMPLES (ASTEROID 25143 ITOKAWA) IMPLIES THEIR SULFIDES FORMED BY THERMAL METAMORPHISM (BEING LL5-6 MATERIAL).THE COMPOSITIONS MORPHOLOGIES AND CRYSTAL STRUCTURES OF SULFIDES ARE DETERMINED BY THEIR FORMATION CONDITIONS INCLUDING TEMPERATURE TIME OXYGEN AND SULFUR FUGACITY AND AQUEOUS AND THERMAL HISTORY. WE PROPOSE TO INVESTIGATE THE STRUCTURES COMPOSITIONS AND CONTEXT OF SULFIDE MINERALS IN SAMPLES RETURNED BY HAYABUSA AND COMPARE THESE WITH SULFIDES IN CHONDRITIC METEORITES. WE WILL CONSTRAIN PARENT BODY FORMATION CONDITIONS OF ASTEROID ITOKAWA BY STUDYING ANALOGOUS SULFIDES WITH PETROGRAPHIC CONTEXT IN CHONDRITIC METEORITES. WE WILL ALSO DEVELOP A SULFIDE DATABASE TO INTERPRET CONDITIONS OF FORMATION FOR SULFIDES THAT WILL LIKELY BE FOUND IN SAMPLES RETURNED BY HAYABUSA2 AND OSIRIS-REX.WE WILL IDENTIFY CANDIDATE SULFIDE GRAINS IN CHONDRITIC METEORITES VIA SCANNING ELECTRON MICROSCOPY (SEM) AND ELECTRON PROBE MICROANALYSIS (EPMA) DETERMINE GRAIN ORIENTATION VIA ELECTRON BACKSCATTER DIFFRACTION (EBSD) AND EXTRACT REPRESENTATIVE SAMPLES VIA FOCUSED-ION-BEAM (FIB) TECHNIQUES. WE WILL STUDY THE COMPOSITION TEXTURE AND CRYSTAL STRUCTURE OF INDIVIDUAL FIB SECTIONS OF THE SULFIDES VIA TRANSMISSION-ELECTRON MICROSCOPY (TEM) TO INVESTIGATE CORRELATIONS BETWEEN FORMATION MECHANISM OXYGEN AND SULFUR FUGACITY TEMPERATURE AND COOLING RATE. WE WILL CONDUCT THE SAME MEASUREMENTS ON ALLOCATED SULFIDE-BEARING HAYABUSA SAMPLES. WE HAVE IDENTIFIED SULFIDES (PYRRHOTITE ((FE NI CO CR)1-XS) AND PENTLANDITE ((FE NI CO CR)9-XS8)) IN LL CI CM AND CR CHONDRITES THAT RECORD EQUILIBRATION TEMPERATURES FROM 100 TO 600DEGREES C. STUDYING SULFIDES IN METEORITES THAT RETAIN THEIR PETROGRAPHIC CONTEXT ALLOWS COMPARISONS BETWEEN ESTABLISHED GEOTHERMOMETERS AND THERMODYNAMIC VARIABLES. SINCE PYRRHOTITE-PENTLANDITE INTERGROWTHS ARE UNCOMMON IN SOME METEORITE GROUPS SULFIDES IN SMALL RETURNED SAMPLES MAY ONLY CONSIST OF PYRRHOTITE OR PENTLANDITE. THEREFORE TO UNDERSTAND SULFIDE FORMATION IN ASTEROIDS IT IS IMPORTANT TO STUDY SULFIDES IN METEORITES WITH WELL-KNOWN FORMATION CONDITIONS TO INVESTIGATE INDICATORS OF FORMATION IN BOTH PYRRHOTITE AND PENTLANDITE. PETROGRAPHIC CHEMICAL AND THERMODYNAMIC ANALYSES ON SULFIDES IN METEORITES VIA SEM EPMA EBSD AND FIB-TEM WILL PROVIDE A DIVERSE SAMPLE SET OF SULFIDES FOR COMPOSITIONAL AND MICROSTRUCTURAL INVESTIGATIONS TO COMPARE WITH RETURNED SAMPLES. THE MOTIVATION FOR THIS RESEARCH IS TO IDENTIFY MICROSTRUCTURAL INDICATORS OF SULFIDE FORMATION CONDITIONS SO THAT PRE- AND/OR POST-ACCRETIONARY FORMATION CONDITIONS CAN BE DETERMINED FOR SAMPLES THAT CONTAIN SULFIDES BUT LACK PETROGRAPHIC CONTEXT AS MAY BE THE CASE FOR RETURNED SAMPLES.THIS RESEARCH IS RELEVANT TO THE SCOPE OF THE LABORATORY ANALYSIS OF RETURNED SAMPLES (LARS) PROGRAM BECAUSE IT AIMS TO 'MAXIMIZE THE SCIENCE DERIVED FROM PLANETARY SAMPLE-RETURN MISSIONS'. LARS IS MOST APPROPRIATE FOR THIS RESEARCH SINCE IT IS RELEVANT TO THE SCOPE OF LARS IN C.18: 'DIRECT ANALYSIS OF SAMPLES ALREADY RETURNED TO EARTH'. THE ANALYSES OF METEORITES ARE APPROPRIATE BECAUSE THEY WILL DIRECTLY SUPPORT THE INTERPRETATION OF RETURNED SAMPLES (SPECIFIED IN 1.3.3 C.18). WE WILL ANALYZE HAYABUSA SAMPLES ALREADY ALLOCATED AND DEVELOP A TIMELY DATABASE OF CHONDRITIC SULFIDES TO ASSIST IN THE INTERPRETATION OF SULFIDES IN RETURNED-SAMPLES OF ASTEROID RYUGU BY HAYABUSA2 IN 2020.