| E | East |
| E/W | East/West (or East-West) |
| EA | Engineering Analysis |
| EA | Enterprise Architecture |
| EA | Environmental Assessment |
| EaaS | ESB as a Service |
| EAC | Estimate At Completion |
| EAL | Evaluation Assurance Level |
| EAM | Enterprise Asset Management |
| EAP | Extensile Authentication Protocol |
| EAR | Engineering Analysis Report |
| EAR | Export Administration Regulations |
| EAWS | Engineering Analysis Workstation |
| EB | Enhancement Build |
| EC | Earth Coverage |
| EC | Environment Canada |
| ECA | Earth Central Angle |
| ECA | Event Correlation and Analysis |
| ECB | Engineering Change Board |
| ECC | Emissive Channel Calibration |
| ECC | Error Correction Circuitry |
| ECCN | Export Commerce Control Number |
| ECD | Estimated Completion Date |
| ECF | Earth Center Fixed |
| ECI | Earth Centered Inertial |
| ECI | Environmental Calibration Initialization |
| ECMWF | European Center for Medium-Range Weather Forecasts |
| ECO | Engineering Change Order |
| ECP | Engineering Change Proposal |
| ECP | Export Control Plan |
| ECR | Engineering Change Request |
| ECR | Environmental Compliance and Restoration |
| ECRA | Electrical Contact Ring Assembly |
| ECRB | Engineering Change Review Board |
| ECSS | European Cooperation for Space Standardization |
| ECT | External Calibration Target |
| EDA | EPP Diagnostic Accelerator |
| EDAC | Error Detection and Correction |
| EDF | Empirical Distribution Function |
| EDOS | Earth Observing System Data and Operations System |
| EDOVO | External Data Operations Validation Objectives |
| EDR | Eddy Dissipation Rate |
| EDR | Environmental Data Record |
| EDS | Error Data Set |
| EDU | Engineering Development Unit |
| EE | Expected Error |
| EED | Electro-Explosive Device |
| EEE | Electrical, Electronic and Electromechanical |
| EELV | Evolved Expendable Launch Vehicle |
| EELV-M | Evolved Expendable Launch Vehicle - Medium |
| EEMCU | ESB Event Messaging Client Utility |
| EEP | Electronically Erasable Program |
| EEZ | Exclusive Economic Zone |
| EF | Expedited Forwarding |
| EFCP | Engineering Functional Checkout Procedure |
| EGSE | Electrical Ground Support Equipment |
| eGVAR | emulated GVAR |
| EHIS | Energetic Heavy Ion Sensor |
| EI | Enterprise Infrastructure |
| EIA | Electronic Industries Alliance |
| EIF | Event Integration Facility |
| EIL | Equipment Identification List |
| EIR | Enhanced Infrared |
| EIR | External Interfaces and Resources |
| EIR | External Interface Router |
| EIRnet | External Interfaces and Resources Network |
| EIRP | Emitted Isotropic Radiated Power |
| EIRP | Equivalent Isotropic Radiated Power |
| EIRR | External Independent Readiness Review |
| EIS | Environmental Impact Statement |
| EIT | Element Integration and Test |
| EIT | Engineering Information Technology |
| ELAN | EGSE-Local Area Network |
| ELDR | Enhanced Low Dose Rate |
| ELDRS | ELDR Susceptible |
| ELT | Emergency Locator Transmitter |
| ELV | Expendable Launch Vehicle |
| EM | Engineering Model |
| EM | Enterprise Management |
| EM | Equivalent Manning |
| EMC | Electromagnetic Compatibility |
| EMC | Embedded Micro Controller |
| EMC | Environmental Modeling Center |
| EMCORE | Environmental Management Center Opportunities Resource |
| EMI | Electromagnetic Interference |
| EMISS4 | 4 µm Emissivity Test |
| EMOC | Engineering Mission Operations Control (VCRM) |
| EMnet | Enterprise Management Network |
| EMOSS | Engineering Mission Operations Support Services |
| EMWIN | Emergency Managers Weather Information Network |
| EMT | Emergency Medical Technical |
| ENG-CTV | Element Energy-Configuration Table Version |
| ENIQ | Ericsson Network IQ |
| ENTCTL | Enterprise Control |
| ENTLN | Earth Networks Total Lightning Network |
| ENVI | Environmental Satellite Processing Center |
| EO | Electro-Optical |
| EO | Engineering Order |
| EO-1 | Earth Observing Satellite 1 |
| EOC | Element of Cost |
| EOC | End-of-charge |
| EOC | End of Contract |
| EOCC | Experiment Operations Control Center |
| EOD | End-of-Discharge |
| EOF | Empirical Orthogonal Function |
| EOL | End of Life |
| EOPP | Earth Oriented Parameter Prediction |
| EOS | Earth Observing System |
| EoS | Economies of Scale |
| EOS | Electro-Optical System |
| EP | Equivalent People |
| EP&D | Electrical Power & Distribution |
| EPA | Environmental Protection Agency |
| EPC | Electrical Power Converter |
| EPC | Electronic Power Conditioner |
| EPC | Engineering Process Council |
| EPCU | Enhanced Power Conditioning Unit |
| EPDM | Enterprise Product Data Management |
| EPEAD | Energetic Proton, Electron, and Alpha Detector |
| EPG | Engineering Process Group |
| EPI | Engineering Process Improvement |
| EPIC | Eclipse Perl Integration |
| EPIRB | Emergency Position Indicating Radio Beacon |
| EPL | Eclipse Public License |
| EPL | Enterprise Process Lifecycle |
| EPO | Emergency Power Off |
| EPP | Earth Pointing Platform |
| EPROM | Erasable Programmable Read Only Memory |
| EPS | Electrical Power Subsystem |
| EPS | Energetic Particle Sensor |
| EQM | Engineering Qualification Model |
| ER | Eastern Range |
| ER/WR | Eastern Range/Western Range |
| ERB | Earth Radiation Budget |
| ERB | Engineering Review Board |
| ERM | Ejector Release Mechanism |
| EROS | Earth Resources Observation and Science |
| ERWIN | Entity Relationship - Windows |
| ES | Enterprise Supervisor |
| ESA | European Space Agency |
| ESB | Enterprise Service Bus |
| ESD | Electro Static Discharge |
| ESLOC | Equivalent Source Line of Code |
| ESM | EGSE System Management |
| ESM | Enterprise Security Manager |
| ESP | Encapsulating Security Payload |
| ESPC | Environmental Satellite Processing Center |
| ESPDS | Environmental Satellite Processing and Distribution System |
| ESRC | Environmental Satellite Resource Center |
| ESRL | Earth System Research Laboratory (NOAA) |
| ESSD | Environmental and Scientific Services Division (National Weather Service) |
| ESSL | Earth and Space Science Laboratory |
| ESSL | European Severe Storms Laboratory |
| ESTE | Electrical System Test Equipment |
| ETA | EUV Telescope Assembly |
| ETC | Estimate to Completion |
| ETE or E-T-E | End-to-End |
| ETEWG | End-to-End Working Group |
| ETL | Engineering Test Labs |
| ETL | Environmental Test Labs |
| ETM | Engineering Test Matrices |
| ETM | Engineering Test Model |
| ETNI | Enterprise Test Name Identifier |
| ETO | Equipment Transfer Order |
| ETROP | Emissivity at Tropopause (Cloud Detection Test) |
| ETS | Engineering and Test Support |
| ETU | Engineering Test Unit |
| EU | Electronics Unit |
| EU | Engineering Units |
| EU | Expected Utility |
| EUMETSAT | European Organization for the Exploitation of Meteorological Satellites |
| EUV | Extreme Ultraviolet |
| EUVS | Extreme Ultraviolet Sensor |
| eV | electron Volts |
| EV | Expected Value |
| EVM | Earned Value Management |
| EVMGR | Event Manager |
| EVMON | Event Monitoring |
| EVMS | Earned Value Management System |
| EVMSG | Event Messaging |
| EVRD | Environmental and Verification Requirements Document |
| EVS | Earned Value System |
| E/W | East/West (or East – West) |
| EWSK | East/West Stationkeeping |
| EXEB | EUVS/XRS Electrical Box |
| EXIS | Extreme Ultraviolet and X-ray Irradiance Sensors |
| EXISE | EXIS Emulator |