On Launch Complex 576-E at Vandenberg Air Force Base in California, workers remove the umbilical tower attached to Orbital Sciences' Taurus XL rocket. Atop the rocket is NASA's Orbiting Carbon Observatory, or OCO, which is scheduled to launch Feb. 24 from Vandenberg. 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 credit: NASA/Richard Nielsen, VAFB