The Costa Rica Aura Validation Experiment (CR-AVE) is a mission designed to explore the tropical upper troposphere and lower stratosphere (UTLS) and to provide information for comparison to satellite observations. The tropical region between 30 N and 30 S comprises half of the Earth’s surface, yet is relatively unsampled in comparison to the mid-latitude of the Northern Hemisphere. In addition, observations above typical aircraft altitudes (40,000 feet or 12 km) are even less frequent, making the tropical upper troposphere and lower stratosphere one of the most sparsely sampled regions of our atmosphere.