It's been a rough birthing process for NASA's Orbiting Carbon Observatory (OCO) satellite program, which promises global tracking of carbon dioxide entering and leaving the atmosphere at ground level. Five years ago the first OCO fell into the Antarctic Ocean and sank, trapped inside the nose cone of a Taurus XL launch vehicle that failed to separate during launch. The angst deepened yesterday when NASA's Jet Propulsion Laboratory (JPL) scrubbed a first attempt to launch a twin of the lost $280-million satellite, OCO-2, after sensors spotted trouble with the launch pad's water-flood vibration-damping system less than a minute before ignition.
But this morning OCO's troubles became history. At 2:56 a.m. PDT a Delta II rocket carrying the OCO-2 satellite roared off the pad at Vandenberg Air Force Base in California. According to JPL, the OCO separated from the Delta II's second stage 56 minutes later and settled into an initial 690-kilometer-high orbit. If all goes well it will maneuver into a final 705-km orbit over the next month, putting it at the head of an international multi-satellite constellation of Earth-observing satellites known as the A-Train.
OCO-2's contribution will be better intelligence on natural sources and sinks for CO2. "Scientists currently don't know exactly where and how Earth's oceans and plants have absorbed more than half the carbon dioxide that human activities have emitted into our atmosphere since the beginning of the industrial era," said David Crisp, OCO-2 science team leader, in a JPL statement released this morning.
OCO-2 will collect more than 100,000 measurements of CO2 concentrations per day beginning in early 2015. It will also monitor plant growth and health by tracking fluorescence given off by plants as they photosynthesize and take up carbon dioxide.
What OCO-2 is not expected to do is to pinpoint anthropogenic emissions of CO2 with sufficient accuracy to test nationally-reported inventories of the world's leading greenhouse gas. Such double-checking from above is becoming possible for methane, another potent agent of climate change, and suggests that the inventories understate methane releases from sources such as oil and gas production. Methane tracking is expected to take a further leap forward with the European Space Agency's €45 million (US $62 million) Tropospheric Ozone Monitoring Instrument (Tropomi), whose launch date recently slid from 2015 to early 2016.
Experts say that tracking CO2 with sufficient resolution and precision to check the inventories could still be five years away because CO2’s absorption signal is harder to isolate than methane’s from the signals of other gases. Missions in development to crack that nut for CO2 include France’s MICROCARB, the European Space Agency’s CARBONSAT, and China’s TanSat minisatellite.