The bucket truck into position over the fairing access door on NASA's Orbiting Carbon Observatory.

On Launch Complex 576-E at Vandenberg Air Force Base in California, Orbital Sciences Engineer Jose Castillo (right) maneuvers the bucket truck into position over the fairing access door on NASA's Orbiting Carbon Observatory, or OCO. Technician Mark Neuse feels for the payload access door through the environmental cover. OCO is scheduled for launch the Taurus rocket 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