NASA's Orbiting Carbon Observatory spacecraft waits atop Orbital Sciences' Taurus XL rocket.

On Launch Complex 576-E at Vandenberg Air Force Base in California, NASA's Orbiting Carbon Observatory, or OCO, spacecraft waits atop Orbital Sciences' Taurus XL rocket to launch Feb. 24. The spacecraft will collect precise global measurements of carbon dioxide (CO2) in the Earth's atmosphere. Scientists will analyze OCO data to improve our understanding of the natural processes and human activities that regulate the abundance and distribution of this important greenhouse gas. Photo courtesy of Glenn Weigle, Orbital Sciences