VANDENBERG AIR FORCE BASE, Calif. – NASA Administrator Charles Bolden talks with representatives of the news media at Space Launch Complex 2 on Vandenberg Air Force Base in California during activities leading up to the launch of NASA's Orbiting Carbon Observatory-2, or OCO-2. Final preparations for launch of OCO-2 at 5:56 a.m. EDT on July 1 aboard a United Launch Alliance Delta II rocket are underway on the pad. OCO-2 is NASA’s first mission dedicated to studying atmospheric carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 will provide a new tool for understanding the human and natural sources of carbon dioxide emissions and the natural "sinks" that absorb carbon dioxide and help control its buildup. The observatory will measure the global geographic distribution of these sources and sinks and study their changes over time. To learn more about OCO-2, visit http://www.nasa.gov/oco2. Photo credit: NASA/Ben Smegelsky