The Halogen Occultation Experiment (HALOE) was launched on the Upper Atmosphere Research Satellite (UARS) spacecraft September 12, 1991, and after a period of outgassing, it began science observations October 11, 1991. The experiment uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction at 4 infrared wavelenths, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the Earth's limb. Latitudinal coverage is from 80S to 80N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to 60-130 km, depending on the species. Nitric oxide measurements extend through the lower thermosphere.HALOE collected its final occultation event on November 21, 2005.