GUVI Global Ultraviolet Imager                                 

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Overview

GUVI is designed to observe the glow of the Earth's upper atmosphere in ultraviolet light so we can better understand the properties of the upper atmosphere. 

GUVI will be used to determine energy inputs from the sun into the Mesosphere and Lower-Thermosphere Ionosphere (MLTI) region of the upper atmosphere where ultraviolet light ionizes the atoms and molecules. This area of Earth's atmosphere is home to the aurora and electrical currents that heat the upper atmosphere during magnetic storms. It's where radio waves are reflected back to Earth making long-distance radio communication possible.

GUVI, a spatial-scanning far-ultraviolet spectrograph, will globally measure the composition and temperature profiles of the MLTI region, as well as its auroral energy inputs. GUVI will look at sources of far-ultraviolet light originating in the Earth's upper atmosphere, such as the aurora, and will count individual particles of light, or photons, emitted by the atmosphere. GUVI is the first instrument sensitive enough to look, in detail, at composition changes in the upper atmosphere.

GUVI will globally scan the MLTI region looking for aurora and other sources of ultraviolet light every 1.5 hours – the time it takes to complete an orbit. During each orbit, GUVI will acquire day, night, and auroral observations. Its very sophisticated, sensitive optical devices will enable us to see and count photons emitted from the upper atmosphere.

 The Johns Hopkins University Applied Physics Laboratory                             The Last Updated: October 17, 2005