WE PROPOSE TO CONTINUE DEVELOPMENT OF THE EUROPA MAGNETOTELLURIC SOUNDER (EMS) AN INSTRUMENT THAT MEASURES AMBIENT ELECTRIC AND MAGNETIC FIELDS TO DETECT UNAMBIGUOUSLY ANY LIQUID WATER WITHIN 30 KM INCLUDING THE OCEAN (EUROPA LANDER SDT OBJECTIVE 2B1). ELECTROMAGNETIC (EM) METHODS ARE OPTIMAL FOR WATER DETECTION ON EUROPA BECAUSE EVEN A SMALL FRACTION OF DISSOLVED SALTS WILL MAKE WATER ORDERS OF MAGNITUDE MORE ELECTRICALLY CONDUCTIVE THAN THE ICE SHELL. THE DISTANCE TO THE NEAREST WATER BODY CAN BE ACCURATELY MEASURED AND THE GEOMETRY OF THAT BODY (E.G. SILL OR DIKE) CAN BE DETERMINED. THE EM FIELDS AROUND EUROPA THAT WOULD SERVE AS SOURCES ARE ALREADY MOSTLY CHARACTERIZED. BOTH ELECTRIC AND MAGNETIC FIELDS ARE REQUIRED (MAGNETOTELLURIC METHOD): A MAGNETOMETER ALONE IS NOT SUFFICIENT BECAUSE THE SOURCE FIELD IS NOT KNOWN INDEPENDENTLY FROM THE RESPONSE AT THE HIGHER FREQUENCIES USED FOR SOUNDING WITHIN THE ICE SHELL. EMS WILL ALSO PROVIDE AN ACCURATE LOCAL MEASUREMENT OF THE ICE-SHELL THICKNESS AND DETERMINE THE DEPTH OF THE OCEAN (EUROPA LANDER SDT OBJECTIVES 2B4 AND 3A4). EMS COMPRISES CENTRAL ELECTRONICS A MAGNETOMETER ON A MAST AND REMOTELY LAUNCHED ELECTRODES TO MEASURE DIFFERENCES IN ELECTRIC POTENTIAL. UNDER CURRENT COLDTECH FUNDING THE PRESENT POINT DESIGN OF EMS WILL ACHIEVE TRL 6 BY THE END OF 2018. THIS INCLUDES FLIGHT-LIKE ELECTRONICS ABLE TO FUNCTION IN THE LANDER VAULT USING A SIMULATED SPACECRAFT INTERFACE FIRST-MOTION DEMONSTRATION OF SENSOR DEPLOYMENT AND FULL OPERATION OF THE DEPLOYED SENSORS IN VACUUM AT EUROPA TEMPERATURE AND RADIATION CHARACTERIZATION OF THE ENTIRE INSTRUMENT. OUR PROPOSED WORK UNDER ICEE-2 HAS THREE THEMES. FIRST WE WILL STUDY INSTRUMENT ACCOMMODATION WITH THE LANDER TEAM INCLUDING THE LOCATION (DECK OR SIDE) OF THE MAGNETOMETER AND ELECTRODE DEPLOYMENT MECHANISMS THE NUMBER AND ORIENTATION OF ELECTRODES AND THE VOLUME AND POWER REQUIRED BY THE CENTRAL (VAULT) ELECTRONICS. SECOND WE WILL IMPROVE THE ELECTROMETER SYSTEM INCLUDING ELECTRONIC AUGMENTATION TO MEASURE BOTH HORIZONTAL COMPONENTS OF THE ELECTRIC FIELD AND TO ALLOW FOR THE FULL RANGE OF PLASMA POTENTIALS LIKELY AT EUROPA S SURFACE VERIFICATION OF CABLE CONSTRUCTION AND WINDING FOR ROBUST DEPLOYMENT AND DEVELOPMENT OF A SIMPLER AND LIGHTER-WEIGHT ELECTRODE-DEPLOYMENT MECHANISM. WE WILL ALSO COLLABORATE WITH SEISMOLOGISTS TO DETERMINE IF SUITABLE SEISMIC SENSORS CAN BE INCORPORATED INTO THE GROUND-CONTACTING REMOTELY DEPLOYED ELECTRODES. THE CHANGES MADE BY THE ACCOMMODATION STUDY AND THE ELECTROMETER IMPROVEMENTS WILL RESULT IN A MORE LANDERRELEVANT DESIGN THAT WILL REQUALIFY TO TRL 6 BY THE END OF THE ICEE-2 POP. THIRD WE WILL ALSO DEVELOP REQUIREMENTS (INCLUDING FURTHER LANDER ACCOMMODATION) CONDUCT PERFORMANCE COST AND RISK TRADES IDENTIFY AND PLAN PROGRAMMATIC RISK MITIGATION AND DEVELOP TIME-PHASED COST AND SCHEDULE ESTIMATES. ALL OF THE PROPOSED WORK BUT ESPECIALLY THIS LAST TASK WILL FACILITATE PREPARATION FOR AN AO DURING OR AFTER ICEE-2.