| g | Earth’s gravitational acceleration |
| G/T | Gain-to-Noise Temperature |
| G&A | General and Administrative |
| GAGL | Government-Allocated Ground Latency |
| GAMCATS | GOES-R Antenna Monitor, Control, and Test Subsystem |
| GAO | Government Accountability Office |
| GAS | GOES-R Access Subsystem |
| GAS | GOES Archive System |
| GB | gigabyte (10E9 bytes) |
| Gbe | Gigabit Ethernet |
| GCA | Gain Control Attenuator |
| GCM | Galois/Counter Mode |
| GCM | Global Circulation Model |
| GCPs | Ground Control Points |
| GCRs | Galactic cosmic rays |
| GCSD | Government Communications Systems Division (Harris Corporation) |
| GD | Ground Directive |
| GDAS | Global Data Assimilation System |
| GDCP | GOES-Derived Cloud Products |
| GDDL | Greenbelt Development and Demonstration La |
| GDE | GOES-R Data Exploitation |
| GDMS | GSFC Directives Management System |
| GDS | Global Domain Server |
| GDST | General Dynamics Space Telecommunications |
| GEO | Geostationary Earth Orbit |
| GEO-CAPE | Geosynchronous Earth Orbit Local User Terminal (COSPAS-SARSAT) |
| GEOCAT | Geostationary Cloud Algorithm Testbed |
| GEOLUT | Geosynchronous Local User Terminal (COSPAS-SARSAT) |
| GEONS | GPS Enhanced Onboard Navigation System |
| GEOPROF | Geometrical Profiling algorithm |
| GEOSAR | Geostationary Earth Orbit Search and Rescue |
| GEOSS | Global Earth Observation System of Systems |
| GeoTIFF | Tagged Image File Format with geo-referencing information |
| GERB | Geostationary Earth Radiation Budget |
| GEVS | General Environmental Verification Standard |
| GEVS-SE | General Environmental Verification Specification for STS & ELV Payloads, Subsystems, and Components |
| GFE | Government Furnished Equipment |
| GFI | Government Furnished Information |
| GFI | Ground fault interrupt |
| GFP | GOES Flight Project |
| GFP | Government Furnished Product |
| GFP | Government Furnished Property |
| GFS | Global Forecast System |
| GFY | Government Fiscal Year |
| CG | Gas Generator |
| GHB | Goddard Space Flight Center Handbook |
| GHe | Gaseous Helium |
| GIA | Government Inspection Agency |
| GID | Goddard Interim Directive |
| GIDEP | Government-Industry Data Exchange Program |
| GIR | GOES Incident Report |
| GIRD | General Interface Requirements Document |
| GIS | General Interface Specification |
| GISS | GOES-R Integrated Scheduling System |
| GIVVWG | GOES-R Integration, Verification, and Validation Working Group |
| GLASH | GOES-Layer Average Specific Humidity |
| GL-C3S | Ground Located – Command, Control, and Communication Segment |
| GLCC | Global Land Cover Characteristics |
| GLD360 | Vaisala Global Lightning Dataset |
| GLM | Geostationary Lightning Mapper |
| GLMBGD | GLM Background Images |
| GLME | Geostationary Lightning Mapper (GLM) Emulator |
| GLMERS | Geostationary Lightning Mapper (GLM) Emulator, Real-Time Node and Simulator |
| GMAG | Goddard Magnetometer |
| GMAO | Global Modeling and Assimilation Office (NASA) |
| GMD | Global Monitoring Division, Earth System Research Lab |
| GMI | Goddard Management Instruction |
| GMIP | Goddard Management Instruction Policy |
| GMIP | Government Mandatory Inspection Point |
| GML | Geography Markup Language |
| GMM | Geometric Math Model |
| GMM | GOES-R Metadata Model |
| GMT | Generic Mapping Tool |
| GN | Ground Network |
| GN&C | Guidance, Navigation and Control |
| GNATS | GOES Navigation Analysis and Trending System |
| GNC&P | Guidance, Navigation, Control and Propulsion |
| GNC | Guidance, Navigation and Control |
| GNSO | Ground Network Scheduling Operator |
| GOCART | Global Ozone Chemistry Aerosol Radiation Transport |
| GOES | Geostationary Operational Environmental Satellite |
| GOES I-M | Geostationary Operational Environmental Satellite-I series |
| GOES-NOP | GOES-N Series satellites |
| GOES-R | Geostationary Operational Environmental Satellite-R series |
| GOES-R3 | GOES-R series Risk Reduction |
| GOESRSCAG | GOES-R Snow Cover and Grain Size |
| GOLD Rules | Goddard Open Learning Design Rules |
| GOME | Global Ozone Monitoring Experiment |
| GOP | Ground Operations Plan |
| GORD | Geostationary Operations Requirements Document |
| GORWG | GOES-R Series Operational Requirements Working Group |
| GORWG | GOES-R Operational Requirements Working Group |
| GOSAT | Japanese "IBUKI", Greenhouse Gas Observing Satellite |
| GOTS | Government Off-The-Shelf |
| GOWG | Ground Operations Working Group |
| GP | Geophysics Directorate |
| GPA | Ground Processing Algorithm |
| GPAD | Ground Processing Algorithm Document |
| GPC | General Purpose Computer |
| GPD | Goddard Policy Directive |
| GPDS | Ground Processing Demonstration System (GLM) |
| GPDS | Ground Processing Development System |
| GPF | GPS-III Processing Facility |
| GPFS | General/Generic Parallel File System |
| GPG | Goddard Procedures and Guidelines |
| GPL | General Public License |
| GPM | Global Precipitation Measurement |
| GPMC | Governing Program Management Council |
| GPO | GOES-R Program Office |
| GPR | Goddard Procedural Requirements |
| GPRA | Government Performance and Results Act |
| GPRD | GOES Program Requirements Document |
| GPS | Global Positioning System |
| GPS-Met | GPS meteorology |
| GPSR | Global Position System Receiver |
| GPWG | GSIT Planning Working Group |
| GQM | Goal-Question Measurement |
| GRAD | GPS Requirements Allocation Document |
| GRATDAT | GOES-R ABI Radiometric Trending and Data Analysis Toolkit |
| GRB | Global Rebroadcast |
| GRB | GOES Rebroadcast |
| GRBT | GRB ground Terminal |
| GRC | Glenn Research Center (NASA) |
| GRD | GOES-R Requirements Document |
| GRD | Ground Segment Readiness Date |
| GRDDP | GOES-R Reliable Data Delivery Protocol (GLM) |
| GRE | Ground Readiness Exercise |
| GRFIWG | GOES Radio Frequency Interference Working Group |
| GRIB | Gridded Binary |
| GRID | Giver-Receiver Inter-Segment Database |
| GRIT | GOES-R Integration and Test |
| GRITT | GOES-R INR Trending Tool |
| GRMS | Goddard Review Management System |
| GRO | Government Residence Office |
| GROW | GOES-R Operations and Warning |
| GRS | General Records Schedule |
| GRS80 | Geodetic Reference System 1980 |
| GRT | Ground Readiness Team |
| GS | Ground Segment/Ground System |
| GS | Ground Station (S/C) |
| GSA | General Services Administration |
| GSAR | Ground Segment Acceptance Review |
| GSC | Ground System Controller |
| GSD | Ground Sample Distance (ABI) |
| GSD | Global Systems Division (ESRL) |
| GSDC | Ground Segment Development Center |
| GSE | Ground Support Equipment |
| GSEDS | Ground Systems Engineering and Depot System |
| GSFC | Goddard Space Flight Center (NASA) |
| GSFPS | Ground Segment Functional and Performance Specifications |
| GSICS | Global Space-based Inter-Calibration System |
| GSIP | GOES Surface and Insolation Project |
| GSIR | Ground System Integration Review |
| GSIT | Ground Segment Integration and Test |
| GSIT | Ground Segment/System Integration Tests |
| GSKMP | GOES-R System Key Management Plan |
| GSM | Ground Segment Mission |
| GSMAR | Ground Segment Mission Assurance Requirements |
| GSP | Ground Segment Plan |
| GSP | Ground Segment Project |
| GSPLA | Ground Segment Post Launch Acceptance |
| GSPM | Ground Segment Project Manager |
| GSPO | Ground Segment Project Office |
| GSPSO | Ground Segment Project Science Office |
| GSRS | Ground Segment Requirements Specification |
| GSRT | Goddard System Review Team |
| GSSE | Ground Segment Systems Engineering |
| GSSIM | Ground Systems Simulator |
| GSV | Ground Segment Verification |
| GSVR | Ground Segment Verification Review |
| GSWTRR | GSE Software Test Readiness (ABI) |
| G/T | Gain-to-Noise Temperature |
| GT | Guide Telescope (SUVI) |
| GTA | Guide Telescope Assembly |
| GTACS | GOES-NQ Telemetry and Command System |
| GTO | Geosynchronous Transfer Orbit |
| GTS | Global Telecommunication System (of WMO) |
| GUC | GOES Users' Conference |
| GUI | graphical user interface |
| GUM | Guide to the Expression of Uncertainty in Measurement |
| GVAR | GOES Variable Data (Legacy GOES) |
| GVF | Green Vegetation Fraction |
| GVI | Global Vegetation Index |
| GWAC | Government-Wide Acquisition Contract |
| GWT | Google Web Toolkit |