Glossary

E

EA Environmental assessment

EAFB Edwards Air Force Base

EELV Evolved Expendable Launch Vehicle

EHF Extremely High Frequency; between 30,000 and 300,000 megacycles per second electromagnetic spectrum A collective term for all known radiation, from the shortest-waved gamma rays through x-rays, ultraviolet, visible light, and infrared waves, to radio waves at the long-waved end of the spectrum

El Niño A warm inshore current annually flowing south along the coast of Ecuador around the end of December and extending about every 7 to 10 years down the coast of Peru

ELV Expendable Launch Vehicle

enthalpy The heat content of a system undergoing change

envelope The operational parameters within which an aircraft can fly

EOS Earth Observing System-a series of satellites, part of NASA's Mission to Planet Earth, being designed for launch at the end of the 1990's to gather data on global change

EOSAT Earth Observation Satellite Company

EOSDIS EOS Data and Information System

EPA Environmental Protection Agency

EROS Earth Resources Observation System

ERS European Remote Sensing Satellite

ERTS Earth Resources Technology Satellite (known as Landsat)

ESA European Space Agency

EUMETSAT European Organisation for the Exploitation of Meteorological Satellites

EVA Extravehicular activity