NASA's first spacecraft dedicated to studying carbon dioxide has arrived at Vandenberg Air Force Base, California, to begin final launch preparations.

The Orbiting Carbon Observatory arrived Nov. 11 at its launch site on California's central coast after completing a cross-country trip by truck from its manufacturer, Orbital Sciences Corp. in Dulles, Virginia. The spacecraft left Orbital on Nov. 8. After final tests, the spacecraft will be integrated onto an Orbital Sciences Taurus rocket in preparation for its planned January 2009 launch. The observatory will help solve some of the lingering mysteries in our understanding of Earth's carbon cycle and its primary atmospheric component, carbon dioxide. Each year, humans release more than 30 billion tons of carbon dioxide into the atmosphere through the burning of fossil fuels. As much as 5.5 billion tons of additional carbon dioxide are released each year by biomass burning, forest fires, and land-use practices such as "slash-and-burn" agriculture. These activities have increased atmospheric carbon dioxide levels by almost 20 percent during the past 50 years. While scientists have a good understanding of carbon dioxide emissions resulting from burning fossil fuels, their understanding of carbon dioxide from other human-produced and natural sources is relatively poor. They know from ground measurements that only 40 to 50 percent of the carbon humans emit remains in Earth's atmosphere; the other 50 to 60 percent, they believe, is absorbed by Earth's ocean and land plants.

The observatory will launch into a 438-mile near-polar, sun-synchronous orbit inclined 98.2 degrees to Earth's equator, mapping the globe once every 16 days. The mission is designed to last two years. It will fly in formation with the five other NASA missions that are part of the "A-Train" or afternoon constellation of Earth Observing System satellites that cross the equator each day shortly after noon. This coordinated flight formation will enable researchers to correlate the observatory's data with data from the other NASA spacecraft, including nearly simultaneous carbon dioxide measurements from the Atmospheric Infrared Sounder instrument on NASA's Aqua satellite. The Orbiting Carbon Observatory is a NASA Earth System Science Pathfinder Program mission managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for NASA's Science Mission Directorate in Washington. Orbital Sciences provides mission operations under JPL's leadership. Hamilton Sundstrand in Pomona, Calif., designed and built the observatory's science instrument. NASA's Launch Services Program at NASA's Kennedy Space Center in Florida is responsible for launch management.