Originally posted on the Nature news blog

NASA has launched its first probe dedicated to mapping the distribution of carbon dioxide in the atmosphere, the agency announced today. The US$465-million Orbiting Carbon Observatory-2 lifted off just before 3 AM local time (11 AM British Summer Time) from Vandenberg Air Force Base in California, after a 1-day delay caused by technical issues with the launchpad.

That is a relief for the US space agency, which tried — and failed — to launch a nearly identical CO2-monitoring probe, the original Orbiting Carbon Observatory (OCO), in 2009. The crash, blamed on a faulty launch vehicle, devastated researchers who had spent years preparing to analyse what would have been some of the first space-borne measurements of atmospheric CO2. “The complete loss of the original OCO mission was heartbreak,” NASA’s OCO-2 project manager, Ralph Basilio, said at a 12 June briefing.

But all hope was not lost: in the wake of the OCO’s failure, the Japan Aerospace Exploration Agency agreed to share the data from its CO2-tracking satellite — GOSAT, launched in January 2009 — with the OCO science team. That helped NASA to test the algorithms that it will use to process and interpret data from OCO-2. “The partnership that we have had with the Japanese has been exceptional,” says Paul Wennberg, an atmospheric scientist at the California Institute of Technology in Pasadena. Wennberg has contributed to developing a network of ground-monitoring stations that have validated GOSAT’s data and will do the same for OCO-2.

If everything goes according to plan, data from the US probe will help researchers track large natural sources and sinks of CO2, such as oceans and forests, and perhaps some manmade sources, such as sprawling urban areas or even large power plants.

From its orbit 705 kilometers above Earth’s surface, OCO-2 will peer down into the atmosphere with a spectrometer, monitoring the level of CO2 in the atmosphere by detecting sunlight reflected by molecules of the greenhouse gas. Each measurement covers a column of air from the satellite to Earth’s surface, with a footprint of roughly 3 square kilometers — much smaller than GOSAT’s 85-square-kilometer footprint.  And the satellite will also spy on plants’ carbon uptake by measuring the weak fluorescence that is produced by chlorophyll during photosynthesis.

This article is reproduced with permission and was first published on July 2, 2014.