GUVI: A hyperspectral imager for geospace

The Global Ultraviolet Imager (GUVI) is an imaging spectrometer on the NASA TEMED spacecraft which was launched on December 7, 2001. This instrument produces a far ultraviolet (FUV) data cube of spatial and spectral information at each step of a scan mirror - that scan mirror covers 140 deg in the cross track direction - a span that includes on limb. GUVI produces simultaneous monochromatic images at five "colors" (121.6 mn, 130.4 nm, 135.6 run, and in broader bands at 140-150 mn and 165-180 mn) as its field of view is scanned from horizon to horizon. The instrument consists of a scan mirror feeding a parabolic telescope and Rowland circle spectrometer, with a wedge-and-strip detector at the focal plane. We describe the design, and give an overview of the environmental parameters that will be measured. GUVI is a modified version of the Special Sensor Ultraviolet Spectrographic Imager (SSUSI), which was launched on the DMSP Block 5D3 F 16 satellite on October 18, 2003 and is slated to fly on DMSP satellites F 17 through F20, as well. We present some results the science analysis of the GUVI data to demonstrate its relevance to the space weather community.