Inside the mobile service tower, or gantry, at Space Launch Complex 2 on North Vandenberg Air Force Base, Calif., the Aura spacecraft is maneuvered into position over the second stage of the Boeing Delta II rocket. After it is mated with the second stage, the fairing will be installed. The latest in the Earth Observing System (EOS) series, Aura is scheduled to launch July 10. Aura’s four state-of-the-art instruments will study the dynamics of chemistry occurring in the atmosphere. The spacecraft will provide data to help scientists better understand the Earth’s ozone, air quality and climate change.