| ZHR | Zenith Hourly Rate | - | Atmospheric Research Center |
| ZCG | Zeolite Crystal Growth | - | Atmospheric Research Center |
| YSO | Young Stellar Object | - | Atmospheric Research Center |
| YSC | Yokohama Science Center | - | Atmospheric Research Center |
| XUV | Extreme Ultraviolet | - | Atmospheric Research Center |
| XMM | X-ray Multi Mirror | - | Atmospheric Research Center |
| WUPPE | Wisconsin Ultraviolet PhotoPolarimter Experiment | - | Atmospheric Research Center |
| WTR | Western Test Range | - | Atmospheric Research Center |
| WSMR | White Sands Missile Range | - | Atmospheric Research Center |
| WSGT | White Sands Ground Terminal | - | Atmospheric Research Center |
| WR | Western Range | - | Atmospheric Research Center |
| WMO | World Meterological Organisation | - | Atmospheric Research Center |
| WIYN | Wisconsin/Indiana/Yale/NOAO Telescope | - | Atmospheric Research Center |
| WINDII | Wind Imaging Interferometer | - | Atmospheric Research Center |
| WIMP | Weakly Interacting Massive Particle | - | Atmospheric Research Center |
| WFPCII | Replacement For WFPC | - | Atmospheric Research Center |
| WFPC | Wide Field/Planetary Camera | - | Atmospheric Research Center |
| WFF | Wallops Flight Facility | - | Atmospheric Research Center |
| WD | White Dwarf | - | Atmospheric Research Center |
| VVS | Voenno-Vosdushniye Sili | - | Atmospheric Research Center |
| VTVL | Vertical Takeoff Vertical Landing | - | Atmospheric Research Center |
| VTHL | Vertical Takeoff Horizontal Landing | - | Atmospheric Research Center |
| VS | SNGVooruzhennikh Sil SNG | - | Atmospheric Research Center |
| VRM | Venus Radar Mapper | - | Atmospheric Research Center |
| VPF | Vertical Processing Facility | - | Atmospheric Research Center |
| VOIR | Venus Orbiting Imaging Radar | - | Atmospheric Research Center |
| VMS | Vertical Motion Simulator | - | Atmospheric Research Center |
| VMF | Voenno-Morskoy Flot | - | Atmospheric Research Center |
| VLT | Very Large Telescope | - | Atmospheric Research Center |
| VLF | Very Low Frequency | - | Atmospheric Research Center |
| VLBI | Very Long Baseline Interferometry | - | Atmospheric Research Center |
| VLBA | Very Long Baseline Array | - | Atmospheric Research Center |
| VLA | Very Large Array | - | Atmospheric Research Center |
| VISSR | Visible/Infrared Spin-Scan Radiometer | - | Atmospheric Research Center |
| VICAR | Graphics Format Used By JPL | - | Atmospheric Research Center |
| VIB | Vertical Integration Building | - | Atmospheric Research Center |
| VHF | Very High Frequency | - | Atmospheric Research Center |
| VFT | Visual Function Tester | - | Atmospheric Research Center |
| VEEGA | Venus-Earth-Earth Gravity Assist | - | Atmospheric Research Center |
| VECO | Vernier Engine Cutoff | - | Atmospheric Research Center |
| VAS | VISSR Atmospheric Sounder | - | Atmospheric Research Center |
| VAFB | Vandenberg Air Force Base | - | Atmospheric Research Center |
| VAB | Vehicle Assembly Building | - | Atmospheric Research Center |
| UVS | Ultraviolet Spectrometer | - | Atmospheric Research Center |
| UVPI | Ultraviolet Plume Instrument | - | Atmospheric Research Center |
| UV | Ultraviolet | - | Atmospheric Research Center |
| UTC | Coordinated Universal Time | - | Atmospheric Research Center |
| UT | Universal Time | - | Atmospheric Research Center |
| USO | Ultra-Stable Oscillator | - | Atmospheric Research Center |
| USN | United States Navy | - | Atmospheric Research Center |
| USMP | United States Microgravity Payload | - | Atmospheric Research Center |
| USML | United States Microgravity Laboratory | - | Atmospheric Research Center |
| USMC | United States Marine Corps | - | Atmospheric Research Center |
| USAF | United States Air Force | - | Atmospheric Research Center |
| USA/RC | Universities Space Automation/Robotics Consortium | - | Atmospheric Research Center |
| UPPP | Union Pour La Promotion De La Propulsion Photonique | - | Atmospheric Research Center |
| UOSAT | University Of Surrey Satellite | - | Atmospheric Research Center |
| UKST | United Kingdom Schmidt Telescope | - | Atmospheric Research Center |
| UIT | Ultraviolet Imaging Telescope | - | Atmospheric Research Center |
| UHF | Ultra High Frequency | - | Atmospheric Research Center |
| UGC | Uppsala General Catalog | - | Atmospheric Research Center |
| UFO | Unidentified Flying Object | - | Atmospheric Research Center |
| UDMH | Unsymmetrical DiMethyl Hydrazine | - | Atmospheric Research Center |
| UBM | Unpressurized Berthing Mechanism | - | Atmospheric Research Center |
| UARS | Upper Atmosphere Research Satellite | - | Atmospheric Research Center |
| U3P | Union Pour La Promotion De La Propulsion Photonique | - | Atmospheric Research Center |
| TWTA | Travelling Wave Tube Amplifier | - | Atmospheric Research Center |
| TTC | Telemetry | - | Atmospheric Research Center |
| TSUP | Tsentr Upravileniya Polyoti | - | Atmospheric Research Center |
| TSTO | Two Stage To Orbit | - | Atmospheric Research Center |
| TSS | Targeted Search System / Tethered Satellite System | - | Atmospheric Research Center |
| TSPK | Tsentr Podgotovka Kosmonavti | - | Atmospheric Research Center |
| TSM | Tail Service Mast | - | Atmospheric Research Center |
| TRMM | Tropical Rainfall Measuring Mission | - | Atmospheric Research Center |
| TPS | Thermal Protection System | - | Atmospheric Research Center |
| TPCE | Tank Pressure Control Experiment | - | Atmospheric Research Center |
| TOS | Transfer Orbit Stage | - | Atmospheric Research Center |
| TOPS | Toward Other Planetary Systems | - | Atmospheric Research Center |
| TOPEX | Ocean Topography Experiment | - | Atmospheric Research Center |
| TOMS | Total Ozone Mapping Spectrometer | - | Atmospheric Research Center |
| TM | Thematic Mapper | - | Atmospheric Research Center |
| TKSC | Tsukuba Space Center | - | Atmospheric Research Center |
| TIROS | Television InfraRed Observation Satellite | - | Atmospheric Research Center |
| TIG | Time Of (until) Ignition | - | Atmospheric Research Center |
| THIR | Temperature/Humidity Infrared Radiometer | - | Atmospheric Research Center |
| TES | Thermal Emission Spectrometer | - | Atmospheric Research Center |
| TEA | Torque Equilibrium Attitude | - | Atmospheric Research Center |
| TDT | Terrestrial Dynamic Time | - | Atmospheric Research Center |
| TDRSS | Tracking And Data Relay Satellite System | - | Atmospheric Research Center |
| TDRS | Tracking And Data Relay Satellite | - | Atmospheric Research Center |
| TCS | Thermal Control System | - | Atmospheric Research Center |
| TCM | Trajectory Control Maneuver | - | Atmospheric Research Center |
| TAU | Thousand Astronomical Unit | - | Atmospheric Research Center |
| TAL | Transatlantic Abort Landing | - | Atmospheric Research Center |
| TAI | International Atomic Time | - | Atmospheric Research Center |
| SWLC | Salt Water Leak Check | - | Atmospheric Research Center |
| SWF | ShortWave Fading | - | Atmospheric Research Center |
| SWAS | Submillimeter Wave Astronomy Satellite | - | Atmospheric Research Center |
| SWAN | Solar Wind Anisotropy Experiment | - | Atmospheric Research Center |
| SUSIM | Solar Ultraviolet Spectral Irradiance Monitor | - | Atmospheric Research Center |
