The Airborne Southern Hemisphere Ozone Experiment (ASHOE) is designed to examine the causes of ozone loss in the Southern Hemisphere lower stratosphere and to investigate how the loss is related to polar, mid-latitude, and tropical processes. ASHOE will be conducted in concert with the campaign, Measurements for Assessing the Effects of Stratospheric Aircraft (MAESA), whose focus is to provide information about stratospheric photochemistry and transport forassessing the potential environmental effects of stratospheric aircraft.