• Dick writes about Earth and planetary science for Science magazine.

All-Too-Familiar Rocket Failure Dooms NASA Climate Mission

4 March 2011 3:09 pm

A rocket's failure early this morning to carry the Earth-observing satellite Glory into orbit shocked engineers, who saw the same sort of disaster doom another climate satellite in 2009. The news stunned climate scientists as well. Both times they lost instruments that could have helped them understand just how bad global warming is going to be, an important mission for NASA that some legislators have questioned.

The Taurus XL rocket made by Orbital Sciences Corp. in Dulles, Virginia, lifted off at about 2:10 PST this morning from Vandenberg Air Force Base in California carrying NASA's Glory satellite in its nose, protected by the usual bullet-shaped shroud, or fairing. All went well until about 3 minutes into the flight, when the fairing was supposed to split open and the two halves peel away. They didn't, so the weight of the fairing—unplanned for late in the rocket burn—dragged it and its payload down, where it crashed somewhere in the South Pacific.

Today's failure was eerily reminiscent of the failure of NASA's Orbiting Carbon Observatory (OCO) launched in February 2009 on another Taurus. Investigators found that, in the case of OCO, the piston mechanism designed to push the halves of the fairing apart was never triggered, Richard Straka of Orbital Sciences said at an early-morning press conference. OCO is resting on the sea floor as a result, not far from where Glory now lies, he said. A new separation mechanism based on gas stored under pressure rather than combustion-produced gas was developed and flown successfully three times last year on Minotaur rockets. But this time, the fourth flight, the mechanism wasn't triggered.

The failure meant the loss of Glory's instrument for measuring the subtle variations in the sun's brightness as the sun heads toward the maximum of its 11-year sunspot cycle. "It's a difficult business, the space business," says solar physicist Judith Lean of the U.S. Naval Research Laboratory in Washington, D.C., who is on the Glory team. "We're trying to understand exactly how the sun varies so it won't be a wildcard in the climate business. It's a terrible loss; you don't have many solar cycles in your lifetime."

The Glory instrument was the most precisely calibrated sun monitor ever and would have ensured a continuous record well into a third solar cycle, though the French satellite Picard launched last June also measures solar brightness.

Glory also carried an instrument that would help scientists understand aerosols' role in countering part of the warming due to greenhouse gases. Most orbiting instruments simply gauge the amount of sunlight scattered from aerosols, but the Glory instrument would have measured the polarization of the scattered light at many different angles.

The information would have allowed identification of the type of aerosol—pollutant sulfate from smokestacks, sea salt from ocean surf, or soot from combustion, for example. That, in turn, would have allowed a better understanding of how most aerosols are countering part of global warming by reflecting sunlight back into space. Knowing how much aerosols are cooling the planet would help policymakers plan for the day when pollutant aerosols likely decrease as countries clean up their economies, exposing the world to the full brunt of greenhouse gases.

"This is a real setback" to aerosol studies, says aerosol researcher Stephen Schwartz of Brookhaven National Laboratory in Upton, New York. "Glory would have made a big difference." One polarimeter has been orbiting since 2004 on board a French satellite, but it is far less capable than Glory's, says climate scientist Gavin Schmidt of NASA's Goddard Institute for Space Studies in New York City. The French version can distinguish aerosol shapes but not composition, he says. Glory's loss, adds Schmidt, reminds scientists once again that studying Earth from space "is still a risky, expensive, and difficult task."

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