SPIE Professional April 2009
Despite the February launch failure of the Orbiting Carbon Observatory (OCO), NASA and other international space agencies continue to advance remote sensing technologies to help answer questions about the impact of human activities—particularly the release of carbon dioxide into the atmosphere—on climate change.
The Japan Aerospace Exploration Agency (JAXA), like NASA, the Indian Space Research Organization, the European Space Agency, and other organizations, has an active earth observation program to solve global environmental problems with international partners.
Photo courtesy of JAXA
JAXA launched the world’s first satellite to measure the density of CO2 in the atmosphere in January. The Greenhouse Gases Observing Satellite (GOSAT) called IBUKI has a Fourier Transform Spectrometer and a Cloud and Aerosol Imager aboard and is expected to be fully operational later this year.
As was expected with OCO before its disappointing failure, measurements from GOSAT will help scientists improve climate models and better understand where CO2 comes from and where it goes. Finding the sources and absorption spots, or sinks, of carbon dioxide in the atmosphere as well as their seasonal variability is crucial to improving forecasting about changes in the Earth's climate and evaluating options for mitigating or adapting to climate change.
The ESA’s contribution to the global effort to observe and understand the Earth’s climate includes the European Remote Sensing (ERS) satellite and Envisat, the largest Earth observation spacecraft ever built. These satellites watch for symptoms of climate change in ice cover, sea level, and sea-surface temperatures and have been called upon to monitor natural disasters in remote parts of the world.
The ESA's "Observing the Earth" program continuously collects images of our planet from space, and they have become powerful scientific tools to enable better understanding and improved management of the Earth and its environment.
In December, ESA released to the public a global land cover map 10 times sharper than any previous global satellite map. The map was generated from 19 months of data between December 2004 and June 2006 from Envisat’s Medium Resolution Imaging Spectrometer instrument working in full resolution mode to provide a spatial resolution of 300 m.
ITRC's POS is a groundbased remote-sensing instrument with a Maksutov-Cassegrain telescope.
Another international player is the Instrument Technology Research Center in Taiwan, which has developed the Panoramic Observation System (POS), a Vegetation and Change Detection imager (VCDi), a microspectrometer for YamSat, and other instruments in its Remote Sensing Laboratory.
Global Climate Change Research Program
The Global Change Research Program (GCRP) is another multi-nation collaboration using remote sensing satellites to answer questions about climate change. Partners in industry and academia from across the globe have designed instruments and spacecraft to make a large-scale examination from space of the relationship between air quality and climate change.
The Earth Observing System Afternoon Constellation, or A-Train, is a series of remote sensing satellites that cross the equator shortly after noon every day to study water, aerosols, gases, and clouds in the atmosphere. Five of the six are operational so far, using cloud profiling radar, lidar, a tropospheric emission spectrometer, and other optical instruments.
OCO, which failed to reach orbit shortly after its February 2009 launch and landed in the ocean off Antarctica, was to have made space-based measurements of atmospheric carbon dioxide with three high-resolution grating spectrometers. It would have been NASA's first effort to measure carbon dioxide in the Earth's atmosphere with the precision, resolution, and coverage needed to determine where it comes from and where it goes.
Rick Obenschain, deputy director at NASA's Goddard Space Flight Center in Maryland, is leading the investigation board into the OCO mishap. Four other voting members are:
- Jose Caraballo, safety manager at NASA's Langley Research Center in Hampton, VA
- Patricia Jones, acting chief of the Human Systems Integration Division in the Exploration Technology Directorate at NASA's Ames Research Center at Moffett Field, CA
- Richard Lynch, Aerospace Systems Engineering, Goddard Space Flight Center
- Dave Sollberger, deputy chief engineer of the NASA Launch Services Program at NASA's Kennedy Space Center in Florida
The investigation team will try to determine why a protective nose cone failed to detach during the launching. According to a report in The New York Times:
"Data received during the launching indicated that the spacecraft's computer had sent commands to set off small explosive charges to split the nose cone in two, like opening a clamshell. The third and fourth stages burned properly, but because of the added weight of the nose cone, the rocket did not accelerate as much as necessary.
"The fairing has considerable weight relative to the portion of the vehicle that's flying," said John Brunschwyler, manager of the Taurus rocket program for the Orbital Sciences Corporation of Virginia, which built the rocket and the satellite.
"So when it separates off, you get a jump in acceleration," he continued. "We did not have that jump in acceleration. As a direct result of carrying that extra weight, we could not make orbit."