 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.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.