NASA’s carbon mission revival under consideration
K.S. RAJGOPAL
— Photo: AFP
Hope endures: An artist’s concept of the Orbiting Carbon Observatory (OCO). The OCO failed to separate from its rocket soon after it was launched on February 23.
The endeavour to combat global warming by mapping the earth’s distribution of carbon dioxide sources and sinks and study their changes over time received a setback, though not a major one, with the failure of NASA’s Orbiting Carbon Observatory (OCO) to reach orbit after its launch on February 23.
The OCO’s measurements were to be combined with data from ground stations, aircraft and other satellites to help answer questions about the processes that regulate atmospheric carbon dioxide and its role in Earth’s climate and carbon cycle.
Is it the end?
Is it the end of the OCO mission? The OCO spacecraft was lost altogether, as it was not designed to survive re-entry. It is most likely that everything except for a handful of small steel and titanium parts disintegrated in the atmosphere before reaching the surface of the Pacific Ocean. Senior Research Scientist, Dr. David Crisp, Principal Investigator, Orbiting Carbon Observatory Mission, noted in an email to this correspondent:
“We built this spacecraft on very a tight budget and produced very few spare parts. We could rebuild the Observatory relatively quickly because we have completed and verified all of the painstaking design work. The team has gained substantial experience in the assembly and testing of the system. As time goes on, this investment will also be lost, as critical parts become obsolete, requiring redesign, and as we lose members of the team to other projects.
“So, while the OCO flight hardware was lost, that was only one part of the system, a substantial fraction of the investment is still recoverable if NASA acts quickly. They have asked our team to assess the cost and schedule needed to rebuild the system, but have not yet made any decision about whether to pursue that option. In a news item released recently, we learned that a decision would be made ‘in the coming month.’”
NASA has also invested heavily in the ground data processing and validation systems, which are now in place and ready to operate. The possibility of using these assets to analyze carbon dioxide measurements from other spacecraft to see whether any of the OCO science objectives can be recovered is being looked into.
Alternative avenues
For example, they have been encouraged to pursue NASA’s ongoing collaboration with the Japanese GOSAT-Ibuki mission, which was also designed to measure carbon dioxide near the surface of the Earth in reflected sunlight.
Also being looked into is the use of data from NASA instruments onboard other spacecraft such as the Atmospheric InfraRed Sounder (AIRS) and Tropospheric Emission Spectrometer (TES). These two instruments measure carbon dioxide higher in the atmosphere, at altitudes around 3-15 km. It had been hoped to combine these measurements with the OCO data to produce a regional scale description of the weak, large scale natural ‘sinks’ that are currently absorbing over half of the carbon dioxide emitted by human activities.
“With the loss of OCO, it should still be possible to identify the more intense, localised sources of carbon dioxide emissions, but the sinks might have to wait,” noted Dr. Crisp. OCO measurements would have been very sensitive to the concentration of carbon dioxide in the Earth’s atmosphere.
OCO would have collected over 500,000 measurements as it flew from pole to pole over the Earth almost 15 times each day.
These carbon dioxide concentration measurements would have been the combined with estimates of the winds, obtained from global atmospheric circulation models, like those used to predict the weather to produce global, time-dependent maps of carbon dioxide.
The global, time dependent maps of carbon dioxide concentrations and the maps of carbon dioxide sources and sinks derived from the OCO data were to have been distributed through an open NASA archive, and would have had many applications.
Many applications
One could easily imagine such tools being used to correlate maps of atmospheric carbon dioxide concentrations with measurements of ocean acidity, or of specific tree or crop distributions on land.
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