THIS IS A PROPOSAL TO CREATE THE ABILITY TO SIMULATE SMILE-SXI DATA AND TO USE THAT ABILITY TO SUPPORT SMILE MISSION DESIGN FROM INSTRUMENT DESIGN THROUGH MISSION/ORBIT PLANNING TO DATA REDUCTION PIPELINE. THE PROPOSED ACTIVITIES DRAW ON THE EXPERTISE PREVIOUSLY DEVELOPED AT JHU FOR CLOSELY RELATED PROJECTS SUCH AS SMM-NEWTON MAGIC DXL DXG OR CUPID BUT MODIFIED TO APPLY TO THE SMILE-SXI PROJECT. THIS PROPOSAL DEMONSTRATES THAT MANY OF THE ESSENTIAL PIECES ARE IN PLACE BUT REQUIRE EFFORT TO MODIFY FOR USE BY SMILE-SXI. MANY OF THE TOOLS FURTHER DEVELOPED HERE WILL BE USEFUL FOR FUTURE NASA PROJECTS. KUNTZ PROVIDES A UNIQUE COMBINATION OF SKILLS FROM BOTH ASTROPHYSICS AND HELIOPHYSICS AS WELL AS ACCESS TO THE INTELLECTUAL RESOURCES OF BOTH FIELD REQUIRED TO SUCCESSFULLY IMPLEMENT THE WORK PLAN. WITH THE EXCEPTION OF ITEMS DISCUSSED IN THE BUDGET NARRATIVE FACILITIES AND STRUCTURES ARE IN PLACE AT JHU TO EXECUTE THIS WORK.