OUR STUDIES WILL ADDRESS SEVERAL OPEN SPACE RADIATION RESEARCH GAPS LISTED IN THE HUMAN RESEARCH ROADMAP. SPECIFICALLY OUR WORK WILL ADDRESS THE FOLLOWING PRIMARY AND SECONDARY RISKS AND CORRESPONDING RELEVANT GAPS: IRP PRIMARY RISK: RISK OF CARDIOVASCULAR DISEASE AND OTHER DEGENERATIVE TISSUE EFFECTS FROM RADIATION EXPOSURE. IRP PRIMARY GAPS RELEVANT TO SPACE RADIATION PROGRAM ELEMENT: DEGEN 1 - USE THE CARDIOVASCULAR TISSUES TO ESTIMATE SPACE RADIATION RISKS FOR DEGENERATIVE HEART AND VASCULAR DISEASES; DEGEN 2 ELUCIDATE UNDERLYING MECHANISMS OF DEGENERATIVE TISSUE CHANGES IN THE HEART AND VASCULAR SYSTEM AND ESTABLISH SURROGATE END POINTS; DEGEN 3 DETERMINE THE PROGRESSION RATES AND LATENCY PERIODS FOR SPACE RADIATIONRELATED DEGENERATIVE CARDIOVASCULAR (CV) DISEASES AS A FUNCTION OF RADIATION TYPE AND ENERGY (GAMMA VS. PROTON VS. HEAVY ION VS. COMBINATION THEREOF) AND IR SEQUENCE. IRP SECONDARY RISK: RISK OF CARDIAC RHYTHM PROBLEMS.