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 O<sub>3</sub>, H<sub>2</sub>O, CH<sub>4</sub>, N<sub>2</sub>O, NO<sub>2</sub>, HNO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub>, CFC-11, CFC-12, ClONO<sub>2</sub>, and aerosols in the upper troposphere, stratosphere, and mesosphere.
After launch, activation of the HIRDLS instrument revealed that the optical path was blocked so that only 20% of the aperture could view the Earth's atmosphere. Engineering studies suggest that a piece of thermal blanketing material ruptured from the back of the instrument during the explosive decompression of launch. Attempts to remove this material mirror failed. However, even with the 80% blockage, measurements at high vertical resolution can be made at one scan angle. HIRDLS failed in March 2008.