THIS PROPOSAL DESCRIBES A PROGRAM TO CONTINUE ISOTOPIC MEASUREMENTS OF STARDUST COMETARY PARTICLES. THE GOAL OF THIS RESEARCH IS TO UNDERSTAND THE CONSTITUENTS AND MAKEUP OF COMET WILD 2 AND TO USE THE INFORMATION TO UNDERSTAND HOW THIS AND OTHER COMETS FORMED LEADING TO A BETTER UNDERSTANDING OF THE ORIGIN OF THE SOLAR SYSTEM. THIS WORK IS PART OF A CONSORTIUM STUDY OF THE CHEMISTRY MINERALOGY PETROLOGY AND ISOTOPIC COMPOSITIONS OF COMET WILD 2 SAMPLES. THIS EFFORT COMBINES SKILLS AND TOOLS AVAILABLE TO ANDREW WESTPHAL S GROUP AT THE UNIVERSITY OF CALIFORNIA AT BERKELEY CONSISTING OF DR. WESTPHAL ANNA BUTTERWORTH ZACK GAINSFORTH AND CHRISTINE JILLY-REHAK AND THOSE OF DR. GARY HUSS AND HIS COLLEAGUES DAVID FRANK AND KAZU NAGASHIMA AT THE UNIVERSITY OF HAWAI I (UH). HOPE ISHII AND JOHN BRADLEY WHO OPERATE THE ADVANCED ANALYTICAL ELECTRON MICROSCOPY CENTER WILL ALSO WORK WITH US. THEY HAVE A TITAN SUPERSTEM (SCANNING TRANSMISSION ELECTRON MICROSCOPE) AND HELIOS DUAL-BEAM FOCUSED ION BEAM (FIB) INSTRUMENT THAT CAN BE USED IN THIS RESEARCH. RYAN OGLIORE NOW AT WASHINGTON UNIVERSITY ST. LOUIS IS ALSO A COLLABORATOR. OUR RESEARCH PROGRAM WILL DRAMATICALLY INCREASE THE NUMBER OF FULLY CHARACTERIZED LARGE TERMINAL PARTICLES THAT HAVE BEEN MEASURED FOR OXYGEN ISOTOPES. THIS WILL PERMIT US TO TEST HYPOTHESES ABOUT THE SOURCE(S) OF THE HIGH-TEMPERATURE MINERAL GRAINS CHONDRULE FRAGMENTS AND CAI FRAGMENTS THAT HAVE BEEN DISCOVERED IN THE WILD 2 SAMPLES. WE WILL ALSO INVESTIGATE THE CHRONOLOGY OF THESE LARGER PARTICLES USING THE 26AL-26MG AND 53MN-53CR CHRONOMETERS. CURRENT DATA SUGGEST THAT THE CHONDRULE AND CAI FRAGMENTS FOUND IN WILD 2 FORMED RELATIVELY LATE A FEW MILLION YEARS AFTER THE FORMATION OF THE FIRST SOLAR SYSTEM SOLIDS. BUT THE DATA ARE LIMITED AND IDENTIFICATION OF EARLY-FORMED OBJECTS AMONG THE SAMPLES WOULD SIGNIFICANTLY CHANGE THE WAY WE CURRENTLY THINK ABOUT THE CONSTITUENTS OF WILD 2. WE WILL CONTINUE TO INVESTIGATE THE SULFUR ISOTOPIC COMPOSITION OF SUITABLE PARTICLES TO LEARN ABOUT HOW THE SULFUR-RICH PARTICLES FORMED AND HOW THEY RELATE TO SULFIDES AND OTHER SULFUR-RICH MATERIALS FROM THE INNER SOLAR SYSTEM. WE WILL INTENSIVELY STUDY ANY PRESOLAR GRAINS THAT ARE IDENTIFIED IN THE COURSE OF THIS WORK. IN ADDITION TO MEASURING THEIR ISOTOPIC COMPOSITIONS WE WILL STUDY PRESOLAR GRAINS AND OTHER ESPECIALLY INTERESTING GRAINS WITH THE TITAN SUPERSTEM. STUDIES OF CHONDRITIC POROUS INTERPLANETARY DUST PARTICLES (IDP) WILL BE CARRIED OUT TO PROVIDE CONTEXT FOR INTERPRETING THE WILD 2 SAMPLES. THE GOAL OF THE LARS PROGRAM IS TO MAXIMIZE THE SCIENCE DERIVED FROM PLANETARY SAMPLE-RETURN MISSIONS. THIS PROJECT IS DESIGNED TO DO THIS FOR THE STARDUST SAMPLES; THE STARDUST MISSION IS EXPLICITLY CALLED OUT IN THE PROGRAM AO. OUR CONSORTIUM APPROACH AND STATE-OF-THE-ART EQUIPMENT PERMIT US TO GET THE MAXIMUM RETURN FROM EACH SAMPLE STUDIED. AT THE END OF THIS PROJECT WE WILL ALL HAVE A BETTER UNDERSTANDING OF COMET WILD 2 ITS CONSTITUENTS AND THE PROCESSES INVOLVED IN THE FORMATION OF THE SOLAR SYSTEM.