Will NASA's Green Space Shot Sink?

NASA plans to launch Feb. 24 its first spacecraft solely dedicated to studying atmospheric carbon dioxide emissions, sending the Orbiting Carbon Observatory into low orbit to measure atmospheric carbon dioxide. The mission is to map the globe from space every 16 days for at least two years in search of human and natural carbon dioxide sources as well as the mysterious carbon dioxide "sinks," the places where carbon dioxide is pulled out of the atmosphere and stored.

Exactly where those sinks are, however, has proved to be elusive for scientists, who have determined only about 40 percent of carbon dioxide emissions have remained in Earth's atmosphere. Of the remaining 60 percent, scientists know about 30 percent can be accounted for in Earth's oceans. The rest have been absorbed in the so-called sinks somewhere on land.

"It's critical that we understand the processes controlling carbon dioxide in our atmosphere today so we can predict how fast it will build up in the future and how quickly we'll have to adapt to climate change caused by carbon dioxide buildup," David Crisp, principal investigator for the Orbiting Carbon Observatory at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

Loaded with three high-resolution spectrometers, the OCO will give scientists about 8 million measurements every two weeks. Each spectrometer focuses on a different, narrow color range, detecting light with the specific colors absorbed by carbon dioxide and molecular oxygen. The less carbon dioxide present in the atmosphere, the more light the spectrometers detect.

NASA says the data from the 300-pound, $273.4 million OCO is critical to measuring global carbon dioxide distribution, allowing scientists to reduce uncertainties in predicting future carbon dioxide increases and make more accurate climate change predictions.

"The Orbiting Carbon Observatory's carbon dioxide measurements will be pivotal in advancing our knowledge of virtually all Earth system land, atmosphere and ocean processes," said Michael Freilich, director of NASA's Earth Science Division in Washington. "They will play crucial roles in refining our knowledge of climate forcings and Earth's response processes."

NASA notes, for instance, that more carbon appears to be taken up by coastal and terrestrial ecosystems in North America than in many other parts of the world. The OCO will help determine the specific roles that Alaska, Canada, the contiguous United States and Mexico are playing in this North American sink.

The OCO will circle Earth every 99 minutes with—NASA hopes—the unprecedented precision, resolution and coverage necessary to completing the first overall picture of the regional-scale geographic distribution and seasonal variations of both human and natural sources of carbon dioxide emissions and their sinks.

"The new mission will provide information to help develop and implement domestic policies and international collaborations to control the movement of carbon in the environment," said Edwin Sheffner, deputy chief of Earth Science at NASA's Ames Research Center, in Moffett Field, Calif. "By identifying and monitoring carbon sources and sinks within a given region, the Orbiting Carbon Observatory will enable comparisons of net carbon dioxide emission sources among regions and counties, and will improve annual reporting of carbon budgets by industrial countries in northern latitudes, and by tropical states with large forests."

The OCO will depart from Space Launch Complex 576-E at Vandenberg Air Force Base, Calif., on a Taurus XL 3110 launch vehicle, a rocket with an 86 percent success rate built by Orbital Sciences and developed under the sponsorship of DARPA (the Defense Advanced Research Projects Agency).

Once in orbit and the high-resolution spectrometers are properly calibrated, the OCO will take the lead position in a constellation of satellites known as the A-Train, crossing the equator shortly after noon each day in coordinated flight formation. The coordination and timing will allow researchers to correlate the OCO'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.

"Major advances in data from satellites, such as OCO, will help us figure out how these different processes are linked and interlinked. We'll be able to sort out the puzzle," said Carlton Hall, manager of the Ecological Program at the Kennedy Space Center. "Earth is like a heat engine. Greenhouse gases trap heat, and that energy has to go somewhere. So even though the actual daily temperatures we experience seem normal, we may see stranger hurricane patterns, colder winters or droughts in places where they've never occurred before."