| Abbreviation | Definition |
|---|---|
| JIR | Job Improvement Request |
| JIS | Joint Integrated Simulation |
| JKT | Jacobus Kapteyn Telescope |
| JO | Job Order |
| JOD | Joint Occupancy Date |
| JOFOC | Justification for Other than Full and Open Competition |
| JOI | Jupiter Orbit Insertion |
| JOIP | Joint Operations Interface Procedure |
| JOP | Jupiter Orbiter Probe (Galileo) |
| JOR | Job Order Request |
| JOV | JOint Venture |
| JOV | Jovial (related to Jupiter) |
| JPC | Joint Power Condition |
| JPDRD | Joint Program Definition and Requirements Document |
| JPF | Jovian Planet Finder |
| JPIC | Joint Program Integration Committee |
| JPOC | JSC (Johnson Space Center) Payload Operations Center |
| JPP | Joint Program Plan |
| JR | Joint Report |
| JRB | Joint Review Board |