Second flight of the Spacelab Grille Spectrometer during the ATLAS‐1 mission

The SPACELAB grille spectrometer on its second space flight during the ATLAS‐1 mission (March 24 ‐ April 2, 1992) took advantage of the favorable timeline and of the extra day to perform more than 65 successful solar occultation runs. It succeeded in obtaining spectra pertinent to its ten target molecules in the full range of altitudes available to the solar infrared occultation technique. These ten molecules are H 2 O, CO, CO 2 , CH 4 , NO, NO 2 , N 2 O, HCl, HF and O 3 . The preliminary analysis of the sunset observation presented here adds new information to the available database on HCl vertical profiles, for assessing long‐term trends of this important stratospheric species.