Orbital Science's Jose Castillo and Mark Neuse remove the fairing payload access door on NASA's Orbiting Carbon Observatory or OCO spacecraft.

With the fairing door off, Orbital Science's Jose Castillo and Mark Neuse remove the fairing payload access door on NASA's Orbiting Carbon Observatory, or OCO, spacecraft on Launch Complex 576-E at Vandenberg Air Force Base in California. Orbital Science's Glenn Weigle and Brett Gladish stand by to take the GN2 flow reading The encapsulated OCO tops Orbital Sciences' Taurus XL rocket, which is scheduled 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