NASA's CO₂-scan sat arrives at launch site

Two year atmo-mapping mission to get facts on carbon cycle

NASA's first satellite dedicated to monitoring atmospheric carbon dioxide has arrived at its launch site. The Orbiting Carbon Observatory will take off from Vandenberg airforce base in January.

According to the space agency, the spacecraft will help to "solve some of the lingering mysteries in our understanding of Earth's carbon cycle and its primary atmospheric component, carbon dioxide".

For all that projected atmospheric carbon levels are now driving political and industrial agendas at the highest level - though cynics would suggest this has been driven by fuel prices and supply-security concerns as much as eco worries - it seems that the processes controlling CO₂ in the air aren't well understood.

NASA says:

Scientists ... know from ground measurements that only 40 to 50 per cent of the carbon humans emit remains in Earth's atmosphere; the other 50 to 60 per cent, they believe, is absorbed by Earth's ocean and land plants.

Scientists do not know, however, precisely where the absorbed carbon dioxide from human emissions is stored ... or whether those processes will continue to work to limit increases in atmospheric carbon dioxide in the future as they do now. The observatory will provide the first complete picture of both human and natural sources of carbon dioxide emissions. It will show the places where they are absorbed, known as "sinks," at regional scales everywhere on Earth. Its data will reduce uncertainties in forecasts of how much carbon dioxide is in the atmosphere and improve the accuracy of global climate change predictions.

This will be achieved using "three first-of-a-kind high-resolution spectrometers" which will use reflected sunlight to analyse the atmosphere beneath them.

The OCO will take up a near-polar orbit at 438 miles up, so covering the entire Earth every 16 days. Its two year mission will see it mapping out carbon spouts and sinks worldwide, in company with NASA's "A-train" earth-observation sat convoy. This will permit cross-checks between the satellites and correlation of measurements, important when looking at a moving picture like the atmosphere.

For those interested, the satellite's launch won't itself involve any significant CO₂ emissions. However, as it is to go up on an all-solid-fuel Taurus stack, there will be a good deal of aluminium oxide and hydrogen chloride. These chemicals are generally seen as rather nastier than ordinary old carbon dioxide, if not such a pressing global issue.

There's more on the OCO from NASA here. ®