ATLAS-3 instruments, mounted on a Spacelab pallet in the cargo bay, included Atmospheric Trace Molecule Spectroscopy ( ATMOS ), which collected more data on trace gases in the atmosphere than on all three of its previous flights combined; Shuttle Solar Backscatter Ultraviolet Spectrometer ( SSBUV ), which took ozone measurements to calibrate ozone monitor on aging NOAA-9 satellite as well as cooperative measurements with other ATLAS-3 instruments; Active Cavity Radiometer Irradiance Monitor ( ACRIM ), which took extremely precise measurements of the sun's total radiation for 30 orbits as calibration reference for sister instrument on Upper Atmosphere Research Satellite ( UARS ) launched in 1991; Measurement of the Solar Constant ( SOLCON ), provided by Belgium, which also measured solar radiation but as reference point to track changes over years; Solar Spectrum Measurement ( SOLSPEC ), French instrument, measured sun's radiation as function of wavelength; and Solar Ultraviolet Spectral Irradiance Monitor ( SUSIM ), which collected its highest precision solar ultraviolet radiation measurements in its 15-year lifetime.
