OCO
Full Name: Orbiting Carbon Observatory
Phase: Development
Launch Date: December 15, 2008
Mission Project Home Page: http://oco.jpl.nasa.gov/
Program(s): Earth System Science Pathfinder
OCO provides space-based observations of atmospheric carbon dioxide (CO2), the principal human-initiated driver of climate change. This mission uses mature technologies to address NASA's highest priority carbon cycle measurement requirement. OCO will generate precise global maps of the abundance of CO2 in the Earth's atmosphere. Scientists will then analyze OCO data to improve our understanding of the natural processes and human activities that regulate the distribution of CO2 in the atmosphere. This improved understanding will enable more reliable forecasts of future changes in the abundance and distribution of CO2 in the atmosphere and the effect that these changes may have on the Earth's climate.
Carbon dioxide is a critical component of the Earth's atmosphere. Since the beginning of the industrial age, the overall concentration of CO2 has increased from about 280 parts per million to over 370 parts per million. This increase represents a change of better than 25% over a very short span of the Earth's history. Scientific studies indicate that CO2 is one of several gases that trap heat near the surface of the Earth. Gases such as CO2 that trap heat in the atmosphere are known as greenhouse gases. Many scientists have concluded that substantial increases in the abundance of CO2 will generate an increase in the globally averaged temperature of the atmosphere. Historical records provide evidence of this trend, which is frequently known as global warming.
Current research indicates that the anticipated changes that might result from an increase in atmospheric CO2 are not so simple. Computer models include changes to ocean currents and to the jet stream that may cause some parts of the Earth to cool while the average temperature increases. Thus, a more correct term for this phenomenon is climate change. Even with extensive measures of CO2 emissions, the processes that govern the carbon cycle are not very well understood. Human activities continue to release a slowly increasing amount of CO2 into the atmosphere. At the same time, measurements of atmospheric CO2 vary drastically from year to year. Without a better understanding of these variations, scientists will have difficulty predicting how the atmosphere will respond in the future. OCO will provide scientists with some of the information that they will need to better understand the carbon cycle. This improved understanding could help policy makers and business leaders make better decisions about how to ensure climate stability and, at the same time, retain our quality of life.
The OCO orbit path will be carefully designed to meet the needs of the experiment. To best measure the spatial variation of global CO2 abundance, OCO measurements will cover as much of the Earth's surface as possible. The Observatory will fly very nearly over the Earth's poles. The near polar orbit ensures that OCO observations will cover most of the Earth's surface at least once every sixteen days. The Observatory will fly in loose formation with a series of other Earth orbiting satellites known as the Earth Observing System Afternoon Constellation, or the A-train. This coordinated flight formation will enable researchers to correlate OCO data with data acquired by other instruments on Earth observing spacecraft. In particular, Earth scientists will compare OCO data with nearly simultaneous measurements acquired by the Atmospheric Infrared Sounder (AIRS) instrument.
The design and architecture of the OCO spacecraft is based on the successful Solar Radiation and Climate Experiment (SORCE) and Galaxy Explorer (GALEX) missions. The power required to run the entire observatory is equivalent to the power needed for six common household light bulbs. The OCO instrument employs a conservative design based upon mature, flight qualified technologies. The OCO payload consists of three classical grating spectrometers. The three channels have independent optics and signal processing electronics. They share a common structure, a single cryogenic cooler and some electronics. The instrument's precision, spectral range, spatial range, measurement resolution and signal to noise ratio all meet or exceed it's performance requirements.
The Jet Propulsion Laboratory will lead the OCO effort. Orbital Sciences Corporation and Hamilton Sundstrand Sensor Systems will partner with JPL to realize this vital mission.