The Orbiting Carbon Observatory (OCO) was a NASA Earth System Science Pathfinder Project (ESSP mission designed to make precise, time-dependent global measurements of atmospheric carbon dioxide (CO2) from an Earth orbiting satellite. Unfortunately, on February 24, 2009, due to a launch vehicle payload fairing anomaly, OCO failed to reach orbit.
However, in December 2009 the Congressional Conference committee directed NASA to allocate no less than $50M for the 2010 fiscal year (FY10) for the initial costs associated with an OCO replacement. The OCO-2 mission underwent critical design review (CDR) in August 2010 and key design point-C (KDP-C) in September 2010. On October 2010, it began the implementation phase.
OCO-2 was built based on the original Orbiting Carbon Observatory mission to minimize cost, schedule and performance impacts. OCO-2 is designed to have a nominal mission time frame of at least two years, but the spacecraft could continue to fly well beyond its prime mission.
OCO-2’s primary science objective is still to substantially increase our understanding of how carbon dioxide sources and sinks are geographically distributed on regional scales and how their efficiency changes over time.
OCO-2 will provide a new tool for understanding both the sources of carbon dioxide emissions and the natural processes that remove carbon dioxide from the atmosphere and how they are changing over time.
Since the start of the Industrial Revolution more than 200 years ago, the burning of fossil fuels, as well as other human activities, have led to an unprecedented build up in this greenhouse gas, which is now at its highest level in at least 800,000 years.
Human activities have increased the level of carbon dioxide by more than 25 percent in just the past half century.
Greenhouse gases, such as carbon dioxide, trap the sun’s heat within Earth’s atmosphere, warming it and keeping it at habitable temperatures. However, scientists have concluded that increases in carbon dioxide resulting from human activities have thrown Earth’s natural carbon cycle off balance, increasing global temperatures and changing the planet’s climate.
While scientists understand carbon dioxide emissions resulting from burning fossil fuels and can estimate their quantity quite accurately, their understanding of carbon dioxide from other human-produced and natural sources is relatively less quantified.
Atmospheric measurements collected at ground stations indicate less than half of the carbon dioxide humans emit into the atmosphere stays there. The rest is believed to be absorbed by the ocean and plants on land.
OCO-2 will help solve this critical scientific puzzle. Quantifying how the natural processes are helping remove carbon from the atmosphere will help scientists construct better models to predict how much carbon dioxide these sinks will be able to absorb in the future.
The mission’s innovative technologies will enable space-based measurements of atmospheric carbon dioxide with the sensitivity, resolution and coverage needed to characterize the sources of carbon dioxide emissions and the natural sinks that moderate their build up, at regional scales, everywhere on Earth.
The mission’s data will help scientists reduce uncertainties in forecasts of how much carbon dioxide is in the atmosphere and improve the accuracy of global climate change predictions.
In addition to measuring carbon dioxide, OCO-2 will monitor the “glow” of the chlorophyll contained within plants, a phenomenon known as solar-induced chlorophyll fluorescence, opening up potential new applications for studying vegetation on land.
NASA researchers, in collaboration with Japanese and other international colleagues, have discovered that data from Japan’s GOSAT (Greenhouse gases observing SATellite, also known as Ibuki in Japan), along with other satellites, including OCO-2, can help monitor this “signature” of photosynthesis on a global scale.
The observatory will fly in a 438-mile (705-kilometer) altitude, near-polar orbit in formation with the five other satellites that are part of the Afternoon, or “A-Train” Constellation.
This international constellation of Earth-observing satellites circles Earth once every 98 minutes in a sun-synchronous orbit that crosses the equator near 1:30 p.m. local time and repeats the same ground track every 16 days.
OCO-2 will be inserted at the head of the A-Train. Once in this orbit, OCO-2 is designed to operate for at least two years. This coordinated flight formation will enable researchers to correlate OCO-2 data with data from other NASA and partner spacecraft.