The first simultaneous observations made from a single DMSP satellite of visible auroral arcs, precipitating primary electrons, and atmospheric bremsstrahlung X rays are presented for a magnetically disturbed auroral event. Measured electron fluxes were used to compute absolute X ray distributions expected at the satellite altitude. The agreement between the calculated and measured X ray spectra is sufficiently good to suggest that the primary electron spectra, which produce structured auroral arcs, can be inferred with an orbiting X ray spectrometer.