STS-45 carried the first Atmospheric Laboratory for Applications and Science (ATLAS-1) experiments, placed on Spacelab pallets mounted in the orbiter's payload bay. The non-deployable payload, equipped with 12 instruments from the United States, France, Germany, Belgium, Switzerland, the Netherlands and Japan, conducted studies in atmospheric chemistry, solar radiation, space plasma physics and ultraviolet astronomy. ATLAS-1 instruments included the Atmospheric Trace Molecule Spectroscopy (ATMOS); Grille Spectrometer; Millimeter Wave Atmospheric Sounder (MAS); Imaging Spectrometric Observatory (ISO); Atmospheric Lyman-Alpha Emissions (ALAE); Atmospheric Emissions Photometric Imager (AEPI); Space Experiments with Particle Accelerators (SEPAC); Active Cavity Radiometer (ACR); Measurement of Solar Constant (SOLCON); Solar Spectrum (SOLSPEC); Solar Ultraviolet Spectral Irradiance Monitor (SUSIM); and Far Ultraviolet Space Telescope (FAUST). Other payloads included the Shuttle Solar Backscatter Ultraviolet (SSBUV) experiment, a Get Away Special (GAS) experiment and six mid-deck experiments.