On Launch Complex 576-E at Vandenberg Air Force Base workers prepare NASA's Orbiting Carbon Observatory.

On Launch Complex 576-E at Vandenberg Air Force Base in California, workers prepare NASA's Orbiting Carbon Observatory, or OCO, upper stack for attachment to the Stage 0. Orbital Sciences workers put the non-flight environmental shield over the fairing prior to erection. A portion of the umbilical tower (above it) is attached to the upper stack. The umbilical tower will be erected along with the upper stack. The spacecraft is scheduled for launch aboard Orbital Sciences' Taurus XL 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/Randy Beaudoin, VAFB