ISOTOPIC INVESTIGATIONS RELEVANT TO ORIGINS OF SOLAR SYSTEMS:WE PROPOSE TO APPLY HIGH-PRECISION 26AL-26MG AND 53MN-53CR CHRONOMETERS TO KEY "MILESTONES" OF THE EARLY SOLAR NEBULA - IN ORDER TO SHED LIGHT ON THE TIMESCALES OF PLANETARY BUILDING PROCESSES. WE WILL USE MULTICOLLECTOR INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY TO PERFORM HIGH PRECISION ISOTOPIC ANALYSES FOR THE PROPOSED WORK. THE NECESSARY EXPERIMENTAL TECHNIQUES WERE DEVELOPED IN THE PI'S LAB FROM THE PRIOR FUNDING CYCLE OF THE ORIGINS PROGRAM - AND HAVE BEEN SUCCESSFULLY APPLIED TO CA-AL-RICH INCLUSIONS (AL-MG) AND CHONDRULES (MN-CR) EXTRACTED FROM PRIMITIVE METEORITES. SECOND - WE PROPOSE A LABORATORY EXPERIMENT TO TEST THE "SELF-SHIELDING" MODEL ADVANCED TO EXPLAIN THE OXYGEN ISOTOPE DISTRIBUTION IN EARLY SOLAR SYSTEM MATERIALS. WE WILL USE THE NEWLY ESTABLISHED ULTRAHIGH-RESOLUTION VACUUM ULTRAVIOLET LASER PHOTODISSOCIATION AND PHOTOIONIZATION FACILITY OF C.Y. NG (CO-I) TO PERFORM CO PHOTODISSOCIATION EXPERIMENTS. WE PROPOSE A DETAILED EXPERIMENTAL SET-UP AND PROCEDURES THAT WOULD ENSURE THE EXPERIMENTAL CONDITIONS ARE REFLECTIVE OF THE SOLAR NEBULAR PHOTOCHEMISTRY OF CO. WE DESCRIBE OUR UNIQUE CAPABILITY AND PREPAREDNESS TO PERFORM THIS TIMELY EXPERIMENT. THE SUCCESS OF THIS EXPERIMENT - TOGETHER WITH OXYGEN ISOTOPE DATA FROM THE GENESIS MISSION - WILL PROVIDE A CRUCIAL PIECE OF INFORMATION IN UNDERSTANDING THE PUZZLE OF THE OBSERVED OXYGEN ISOTOPE ANOMALIES IN THE SOLAR SYSTEM - KNOWN FOR OVER THREE DECADES BUT DEFYING A CONSENSUS EXPLANATION TO THIS DAY. THIS EXPERIMENTALLY-FOCUSED RESEARCH PROPOSAL IS HIGHLY RELEVANT TO THE SCOPE OF THE ORIGINS OF SOLAR SYSTEMS PROGRAM: THROUGH THE LABORATORY ANALYSIS OF PRIMITIVE MATERIALS TO UNDERSTAND THE DIVERSITY OF CHEMICAL AND PHYSICAL CONDITIONS IN THE SOLAR NEBULA LEADING TO THE FORMATION OF PLANETARY SYSTEMS. THE PROPOSED INVESTIGATION SUPPORTS ONE OF THE FOUR GOALS OF THE ORIGINS OF SOLAR SYSTEMS PROGRAM: STUDIES OF CHEMICAL AND ATOMIC PROCESSES RELATED TO THE FORMATION OF PLANETARY SYSTEMS. THE PROPOSAL REPRESENTS AN OPPORTUNITY FOR COLLABORATIVE RESEARCH WITH THE EXISTING POTENTIAL AT UNIVERSITY OF CALIFORNIA AT DAVIS FOR COMPLEMENTARY INTERDISCIPLINARY EFFORTS TO SOLVE KEY SCIENTIFIC QUESTIONS - AS ENCOURAGED EXPLICITLY BY THE ORIGINS OF SOLAR SYSTEMS PROGRAM. THE PROPOSED RESEARCH ACTIVITIES SUPPORT NASA STRATEGIC GOALS (SUB-GOAL 3C) TO ADVANCE SCIENTIFIC KNOWLEDGE OF THE ORIGIN AND HISTORY OF THE SOLAR SYSTEM. THE OUTCOME OF THE PROPOSED RESEARCH WILL LEAD TO PROGRESS IN LEARNING HOW THE SUN S FAMILY OF PLANETS AND MINOR BODIES ORIGINATED AND EVOLVED (NASA RESEARCH OBJECTIVE 3C.1) - AND IN UNDERSTANDING HOW INDIVIDUAL STARS FORM AND HOW THOSE PROCESSES ULTIMATELY AFFECT THE FORMATION OF PLANETARY SYSTEMS (NASA RESEARCH OBJECTIVE 3D.3). OUR EFFORTS WILL HELP TO ATTRACT AND RETAIN STUDENTS IN SCIENCE / TECHNOLOGY / ENGINEERING / AND MATHEMATICS DISCIPLINES (STEM); THUS STRENGTHENING NASA AND THE NATION S FUTURE WORKFORCE - AND ENGAGE MORE AMERICANS IN NASA'S MISSION.