Accession Number : ADA114603

Title :   A Satellite-Borne Limb Scanning Ultraviolet Spectrometer for Thermospheric Remote Testing.

Descriptive Note : Technical rept.,


Personal Author(s) : Pranke,James B ; Christensen,Andrew B ; Morse,F A ; Hickman,David R ; Chater,William T

PDF Url : ADA114603

Report Date : 30 Apr 1982

Pagination or Media Count : 49

Abstract : A concave grating Wadsworth spectrometer designed to scan the ultraviolet limb of the earth was flown on a DoD satellite to obtain measurements of atmospheric emissions in the wavelength range of 85 nm to 395 nm as a function of height above the solid earth. The instrument field of view was 0.14 deg x 3.8 deg corresponding to 8 km in the vertical and 230 km in the horizontal at the limb. Scanning motion was controlled by a momentum-compensated DC-torque motor mechanism that panned the line of sight across the limb corresponding to tangent altitudes of 80 km to 480 km. A set of three photon counting detectors, each viewing a separate exit slit, provided simultaneous coverage of the wavelength bands 85-120 nm (EUV), 110-163 nm (FUV) and 290-395 nm (UV), respectively. A separate photometric channel isolated the atmospheric sodium doublet at 589.0-589.6 nm. The grating position and instrument view angle were controlled by digital circuitry operating on hardwired and uplinked command instructions. The operating modes included a variety of scanning and fixed wavelength and view angle operations. A description of the instrument and several examples of the data are presented. These include the dayglow emissions from thermospheric oxygen and nitrogen that form the basis of a thermospheric density determination; auroral enhancements observed in these emissions and in hydrogen Ly alpha; and night-time sodium emissions.

Descriptors :   *Ultraviolet spectrometers, *Remote detectors, *Thermosphere, Scanning, Meteorological satellites, Atmospheric chemistry, Density, Drag, Predictions, Emission spectra, Hydrogen, Oxygen, Nitrogen, Sodium, Airglow, Aurorae, Night, Day

Subject Categories : Atmospheric Physics
      Test Facilities, Equipment and Methods
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE