RESOLVING THE INTERIOR STRUCTURE OF PLANETARY BODIES IS OF FUNDAMENTAL IMPORTANCE IN OUR UNDERSTANDING OF THE ORIGIN AND EVOLUTION OF PLANETS MOONS AND SMALL BODIES. AMONG SEVERAL TOOLS AVAILABLE TO STUDY THE DEEP INTERIOR ARE NATURAL SOURCE ELECTROMAGNETIC (EM) SOUNDINGS WHICH HAVE PREVIOUSLY BEEN USED TO STUDY THE INTERIORS OF THE MOON EARTH AND THE GALILEAN SATELLITES. EM METHODS UTILIZE THE PRINCIPLE OF INDUCTION IN WHICH THE RESPONSE OF THE CONDUCTING INTERIOR TO INCIDENT ELECTROMAGNETIC FLUCTUATIONS ENABLES AN ESTIMATE OF THE INTERNAL ELECTRICAL CONDUCTIVITY. BY DETERMINING THE ELECTRICAL CONDUCTIVITY AS A FUNCTION OF DEPTH EM SOUNDINGS CAN RESOLVE OR CONSTRAIN THE CORE SIZE UPPER AND LOWER MANTLE STRUCTURE COMPOSITION AND THERMAL STATE AND EVOLUTION AMONG OTHER PROPERTIES OF INTEREST. DESPITE SIGNIFICANT PROGRESS IN CONSTRAINING THE CORE AND MANTLE STRUCTURE USING EM SOUNDINGS AT THE MOON THE EFFECTS OF SOLAR WIND PLASMA WERE UNDERESTIMATED AND SIMPLIFIED ASSUMPTIONS WERE APPLIED FOR THE BOUNDARY CONDITIONS IMPOSED BY THE SOLAR WIND INTERACTION. MOREOVER EM SOUNDING HAS NOT BEEN STUDIED AT OTHER TERRESTRIAL AIRLESS BODIES THAT MAY HAVE DIFFERENTIATED INTERIORS SUCH AS 1 CERES 4 VESTA AND 16 PSYCHE. WE WILL APPLY FOR THE FIRST TIME A SELF-CONSISTENT MODEL THAT SIMULATES BOTH THE INDUCTIVE RESPONSE AND EXTERNAL ELECTROMAGNETIC ENVIRONMENT TO THE STUDY OF EM INDUCTION AT FOUR INNER SOLAR SYSTEM BODIES: THE MOON 1 CERES 4 VESTA AND 16 PSYCHE. OUR APPROACH WILL INTEGRATE A PLASMA HYBRID SIMULATION OF THE SOLAR WIND INTERACTION WITH THESE TERRESTRIAL AIRLESS OBJECTS WITH THE INDUCTIVE RESPONSE OF THE INTERIORS OF THESE OBJECTS. OUR EFFORT USES AN ESTABLISHED HYBRID MODEL WITH A SUCCESSFUL TRACK RECORD IN THE SIMULATION OF THE MOON-SOLAR WIND INTERACTION MODIFIED TO INCLUDE THE CONDUCTIVE INTERIOR AND THE INDUCED FIELDS THAT ARE GENERATED DUE TO SOLAR WIND DISTURBANCES. BY COMPARING FOUR SELECT OBJECTS THE MOON 1 CERES 4 VESTA AND 16 PSYCHE WE WILL ADDRESS THE FOLLOWING CORE GOALS AND KEY SCIENTIFIC QUESTIONS: 1. QUANTIFY THE NATURE ROLE AND IMPORTANCE OF INDUCED FIELDS IN THE SOLAR WIND INTERACTION FOR EACH OBJECT. 2. CHARACTERIZE THE EFFECTS OF OBJECT SIZE SHAPE INTERIOR STRUCTURE AND CONDUCTIVITY ON THE INDUCED EM RESPONSE OF THE INTERIOR AND ITS COUPLING WITH THE SURROUNDING PLASMA ENVIRONMENT. 3. SUPPORT OR REFUTE THE MAJOR ASSUMPTIONS MADE DURING THE APOLLO EM SOUNDING EXPERIMENTS AT THE MOON REGARDING THE SOLAR WIND INTERACTION AND BOUNDARY CONDITIONS FOR INDUCED MAGNETIC FIELDS AT THE MOON AND DETERMINE WHETHER THESE ASSUMPTIONS HOLD AT OTHER TERRESTRIAL AIRLESS BODIES IN THE SOLAR WIND. 4. UNDERSTAND AND DEMONSTRATE THE UTILITY OF THIS MODEL FOR THE PREDICTION AND INTERPRETATION OF EM SOUNDING OF THE INTERIOR STRUCTURE OF TERRESTRIAL AIRLESS BODIES ON FUTURE MISSIONS SUCH AS A LUNAR GEOPHYSICAL NETWORK AND ANY FUTURE MISSION TO LARGER ASTEROIDS LIKE THE PROPOSED NASA DISCOVERY MISSION TO 16 PSYCHE. OUR INTERDISCIPLINARY EFFORT IS HIGHLY RELEVANT TO THE GOALS OF THE SOLAR SYSTEM WORKINGS SOLICITATION PROVIDING KNOWLEDGE ABOUT THE INTERIOR STRUCTURE OF SELECT TERRESTRIAL AIRLESS OBJECTS WHILE ALSO YIELDING INSIGHTS INTO POTENTIALLY IMPORTANT ASPECTS OF PLASMA INTERACTIONS WITH SMALL BODIES IN THE SOLAR WIND. THIS RESEARCH WILL PROVIDE A FRAMEWORK FOR THE INTERPRETATION OF INDUCED FIELDS AROUND AIRLESS BODIES IN TERMS OF THEIR INTERIOR STRUCTURE AND ULTIMATELY THEIR GEOPHYSICAL ORIGINS. MEASURING THE INTERIOR STRUCTURE OF THE MOON AND OTHER TERRESTRIAL OBJECTS IS AN INTEGRAL PART OF UNDERSTANDING THEIR FORMATION AND EVOLUTION WHICH IS A CENTRAL GOAL DESCRIBED IN BOTH THE NASA STRATEGIC AND SCIENCE PLANS. GAINING A DEEPER UNDERSTANDING OF THE MOON S LOWER MANTLE IS A SPECIFIC GOAL LISTED IN THE MOST RECENT DECADAL SURVEY IN PLANETARY SCIENCE VISIONS AND VOYAGES FOR PLANETARY SCIENCE IN THE DECADE 2013-2022.