OBSERVATION OF THE UV SOLAR SPECTRAL IRRADIANCE BETWEEN 200 AND 350 NM DURING THE ATLAS-I MISSION BY THE SOLSPEC SPECTROMETER

The SOLSPEC instrument has been built to carry out solar spectral irra diance measurements from space. It consists of three spectrometers des igned to measure the solar spectral irradiance from 180 to 3000 nm. It flew for the first time in December 1983 with the SpaceLab 1 mission (SL1) and later with the ATLAS missions after significant improvement of the instrument optics and calibration procedures. For the ATLAS 1 m ission in March 1992, the thermal conditions encountered during the me asurements were better than those of SL1, leading to better data quali ty. Furthermore, other Sun spectrometers, two on the same platform and two others on board the Upper Atmosphere Research Satellite, have als o carried out UV absolute spectral measurements at the same time. Thes e opportunities allowed comparisons of solar irradiance determinations . The UV part of the measurements made during that mission is presente d here as well as its calibration and accuracy analysis.