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OCO 2 makes its first carbon measurement from space

Posted: August 13, 2014

A satellite launched last month has reached its operational perch 438 miles above Earth and started collecting data on the global distribution of carbon dioxide, a gas linked to climate change, NASA announced this week.

Artist's concept of the OCO 2 spacecraft. Credit: NASA/JPL-Caltech
The $468 million Orbiting Carbon Observatory 2 mission will spend at least two years identifying sources and sinks of atmospheric carbon dioxide, places where the gas is emitted into the atmosphere and absorbed back into oceans and plants.

After its release into a preliminary orbit after launching July 2 aboard a Delta 2 rocket, OCO 2 raised its altitude to join a network of NASA and international Earth observation satellites flying in formation around the planet once every 98 minutes.

The "A-train" satellite constellation allows scientists to compare observations from multiple satellites each designed to measure different parts of the Earth's atmosphere, climate, oceans and land.

OCO 2 is positioned at the "head" of the A-train as its spectral instrument measures the glint of sunlight reflected off the column of carbon dioxide in the atmosphere.

The spacecraft arrived in its final operational position Aug. 3, according to NASA.

Japan's GCOM W1 water cycle research observatory and NASA's Aqua, CALIPSO, CloudSat and Aura satellites fly in the A-train behind OCO 2. The satellites fly over roughly the same location on Earth within 16 minutes of each other.

The half-ton satellite will not only track the geographical distribution of carbon dioxide, but its single science sensor will also monitor how concentrations of the greenhouse gas change with the seasons.

OCO 2 launched July 2 on a Delta 2 rocket from Vandenberg Air Force Base in California. Credit: NASA/Bill Ingalls
Scientists say carbon dioxide is the leading human-produced greenhouse gas driving climate change, so understanding the carbon cycle is important for quantifying the role of fossil fuels in carbon dioxide production and forecasting how concentrations of the greenhouse gas will change in the future.

Satellite monitoring of carbon dioxide could yield a significant leap in understanding how the carbon cycle is linked to global warming.

With OCO 2 at its intended altitude, ground controllers began cooling down the satellite's spectral instrument to bring it into focus, according to a NASA press release.

The instrument collected its first data Aug. 6.

"The initial data from OCO-2 appear exactly as expected -- the spectral lines are well resolved, sharp and deep," said Randy Pollock, OCO 2 chief architect and calibration lead at NASA's Jet Propulsion Laboratory. "We still have a lot of work to do to go from having a working instrument to having a well-calibrated and scientifically useful instrument, but this was an important milestone on this journey."

Officials say calibration of OCO 2's instrument will continue for several more weeks, followed by testing of the mission's data processing system on the ground.

Spectral data from OCO 2 will be available for dissemination to the global science community before the end of the year, followed by delivery of estimates of carbon dioxide to scientists in early 2015, NASA officials said.

Follow Stephen Clark on Twitter: @StephenClark1.