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 the 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.