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| JBO | Jodrell Bank Observatory | JCMT | James Clark Maxwell Telescope | JEM | Japanese Experiment Module | JEWM | Joint Expert Working Meeting | JIVE | Joint Institute for VLBI in Europe | JIWP | Joint Interim Working Party | JPL | Jet Propulsion Laboratory | JPOP | Japanese Polar Platform | JSS | Joint Surveillance System | JTIDS | Joint Tactical Information Distribution System | |