The High Resolution Dynamics Limb Sounder (HIRDLS) is an instrument on board the NASA Aura. It follows in the heritage of LRIR (Nimbus-6), LIMS and SAMS (Nimbus-7), ISAMS and CLAES (UARS). It was designed to observe global distribution of temperature and concentrations of O3, H2O, CH4, N2O, NO2, HNO3, N2O5, CFC-11, CFC-12, ClONO2, and aerosols in the upper troposphere, stratosphere, and mesosphere.