.THIS IS A PROPOSAL FOR A COOPERATIVE AGREEMENT BETWEEN NASA GODDARD SPACE FLIGHT CENTER (GSFC) AND THE SMITHSONIAN ASTROPHYSICAL OBSERVATORY (SAO) OF CAMBRIDGE MASSACHUSETTS. THE AGREEMENT WILL CONTINUE AND EXPAND THE EXTREMELY PRODUCTIVE TEAMING RELATIONSHIP BEGUN WITH THE HITOMI MISSION AND NOW THE XRISM MISSION. THE PROPOSED AGREEMENT WHEN PUT IN PLACE WILL ENSURE THAT THE UNIQUE EXPERTISE AND INSIGHT OF THE SAO TEAM WILL BE MADE AVAILABLE TO NASA AS PART OF THE US PARTICIPATION IN XRISM.. BECAUSE OF THE POTENTIAL FOR EVOLUTION IN THE US INVOLVEMENT IN XRISM AS WELL AS CHANGES IN THE NEEDS OF THE XRISM TEAM THE FLEXIBILITY OF A COOPERATIVE AGREEMENT IS IN THE BEST INTEREST OF BOTH NASA/GSFC AND SAO. THE FOLLOWING SUBSECTIONS OUTLINE AREAS WHERE SAO EXPECTS TO PROVIDE IMPORTANT HIGH LEVEL AND UNIQUE SUPPORT TO NASA IN FORMULATING AND PROVIDING THE US COMMITMENT TO THE XRISM. .THIS DESCRIPTION OF AREAS OF PARTICIPATION IS NOT A STATEMENT OF WORK. RATHER IT DEFINES THOSE AREAS WHERE IT IS ANTICIPATED THAT SAO CAN MAKE THE MOST MEANINGFUL CONTRIBUTION AND IN THAT SENSE SHOWS HOW SAO IS ABLE TO COMPLEMENT (AND SUPPLEMENT) THE GSFC TEAM WITH ALL STAFF WORKING TOGETHER UNDER THE OVERALL DIRECTION OF THE XRISM PROJECT SCIENTIST. .THIS STATEMENT OF COLLABORATION OUTLINES HOW THE SMITHSONIAN ASTROPHYSICAL OBSERVATORY (SAO) WILL CARRY OUT ITS TECHNICAL SCIENTIFIC AND MANAGEMENT SUPPORT ROLE IN FORMULATION PLANS FOR IMPLEMENTING XRISM X-RAY SCIENCE IN PARTNERSHIP WITH THE XRISM PROJECT SCIENTIST AND THEIR TEAM AT THE NASA GODDARD SPACE FLIGHT CENTER (GSFC). .THE CORE SCIENTIFIC STAFF THAT HAS SUPPORTED EARLIER PHASES OF THE HITOMI TEAM AND NOW THE XRISM PROGRAM WILL UNDER THIS PROPOSAL CONTINUE TO SUPPORT THE EFFORTS WITH GSFC COMMENSURATE WITH THE AVAILABLE BUDGETS. 3 REQUESTED FUNDING .