Accession Number:

ADA114603

Title:

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

Descriptive Note:

Technical rept.,

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB

Report Date:

1982-04-30

Pagination or Media Count:

49.0

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.

Subject Categories:

  • Atmospheric Physics
  • Test Facilities, Equipment and Methods
  • Unmanned Spacecraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE