IGF::OT::IGFRESEARCH&DEVELOPMENT PROCUREMENT. NASA GSFC HAS THE RESPONSIBILITY TO BUILD THE PROPULSION SYSTEM IN SUPPORT OF THE EUROPA MISSION. THIS ENGINE WILL BE THE ONLY PROPULSION ON THE EUROPA CLIPPER SPACECRAFT. THE DUAL SPLIT TRIPLET-13 (DST-13) ENGINE HAS BEEN IDENTIFIED BY JPL AND JH/APL AS THE ONLY ENGINE THAT CAN MEET THE EUROPA MISSION REQUIREMENT. THE DST-13 ENGINE CONSISTS OF TWO MAIN PARTS: (1) A VALVE WHICH CONTROLS THE PROPELLANT FLOW TO THE ENGINE AND (2) THE ENGINE ASSEMBLY WHICH CONTAINS THE PROPELLANT INJECTOR, COMBUSTION CHAMBER AND EXPANSION NOZZLE. THE FOLLOWING THREE REQUIREMENTS HAVE BEEN IDENTIFIED TO CONDUCT A RISK REDUCTION PROGRAM TO DEVELOP A MODIFIED VERSION OF THE DST-13 ENGINE FOR THE EUROPA SPACECRAFT: (1) DEVELOP A MODIFIED VERSION OF THE MOOG 51-78 SINGLE SEAT SOLENOID VALVE AND FABRICATE THREE SOLENOID VALVES. THIS REQUIREMENT IS TO CHANGE THE VALVE FROM A DUAL SEAT CONFIGURATION TO A SINGLE SEAT CONFIGURATION IN ADDITION TO CHANGING THE VALVE SEAT MATERIAL FROM TEFLON POLYTETRAFLUOROETHYLENE (PTFE) TO TEFLON PERFLUOROALKOXY (PFA). THIS MATERIAL CHANGE IS NECESSARY BECAUSE THE PTFE WILL NOT SURVIVE IN THE SEVERE RADIATION ENVIRONMENT THAT THE EUROPA SPACECRAFT WILL ENCOUNTER DURING THE JUPITER ORBIT. (2) DEVELOP A THRUST CHAMBER WITH A PARTIALLY COATED NOZZLE. THE CURRENT NOZZLE ON THE DST-13 ENGINE IS FULLY COATED WITH HAFNIUM OXIDE (HFO). THIS REQUIREMENT IS TO PARTIALLY COAT THE ENGINE EXPANSION NOZZLE WITH A (HFO) COATING. A PARTIALLY COATED VERSION IS NECESSARY IN ORDER TO REDUCE THE HEAT LOSS FROM THE SPACECRAFT DURING THE LONG CRUISE PHASE OF THE MISSION. (3) CONDUCT TESTS ON VALVE AND NOZZLE. GSFC WILL SUPPLY A DST-13 ENGINE THAT WAS USED DURING THE EUROPA ENGINE DEVELOPMENT TESTS AT MOOG IN SEPTEMBER, 2016. THE ENGINE IS THE PROTOTYPE FOR THE EUROPA FLIGHT ENGINE. ONCE THE MODIFICATIONS DESCRIBED ABOVE ARE COMPLETE, THE ENGINE WILL BE SUBJECTED TO SHOCK, VIBRATION AND HOT FIRE TESTING TO VALIDATE IT HAS THE CAPABILITY TO MEET THE EUROPA MISSION REQUIREMENTS.