U.S. Prepares to Launch Flawed Satellite

Abstract

EARTH OBSERVING The U.S. government is planning to fly an Earth-observing satellite that will be essentially colorblind, at least as far as the oceans are concerned. The NPP satellite is a prototype for the $12 billion National Polar-orbiting Operational Environmental Satellite System (NPOESS), a series of satellites to be launched between 2013 and 2022. In 2006, scientists learned that there was a problem with the filter on one of NPP's instruments, VIIRS, which will prevent it from accurately measuring ocean color, a window into how sea life responds and contributes to fluctuating atmospheric and ocean carbon. But officials with NASA and the National Oceanic and Atmospheric Administration (NOAA) rebuffed a request last fall from scientists to correct the problem out of concern that working on the filter could jeopardize the other 21 parameters that VIIRS measures, including clouds, the extent of ice sheets, and forest cover. Last month, NOAA announced that a glitch in the system to regulate the satellite's temperature would push back the mission by 8 months, to 2010, prompting scientists to ask the government to use the delay to at least conduct a risk-benefit analysis of correcting the filter problem. Last week, NOAA officials told Science that they have no plans to do such an analysis or to alter the timetable to accommodate any changes to VIIRS's filters. Instead, says NPOESS manager Dan Stockton, the agency will try to fix the ocean-color problem “for the first NPOESS” mission set to launch in 2013. ![Figure][1] Bloomin' brilliant. NASA's 9-year-old Terra is living on borrowed time but still provides good data for studies of plankton blooms. CREDIT: GSFC/NASA Scientists fear that the flaws in NPP will disrupt the longitudinal record on ocean color, because two experimental NASA craft now providing good data are near or beyond their 5-year design life. Color data from a European satellite have been difficult to use, and an Indian sensor has yet to be launched, they add. “Are we going to [make it] to NPOESS [in 2012]? I don't think so,” says David Siegel, a marine scientist at the University of California, Santa Barbara. But Art Charo, who follows the issue for the U.S. National Academies' National Research Council, points out that the ocean-color community is at least better off than other climate specialties that had instruments removed from NPOESS in 2006 and don't know whether they will be restored ( Science , 31 August 2007, p. [1167][2]). “With such a tight budget environment, it's a question of triage,” he says. [1]: pending:yes [2]: /lookup/doi/10.1126/science.317.5842.1167