Published online 4 March 2011 | Nature | doi:10.1038/news.2011.138

News

NASA satellite crashes to Earth

The loss of Glory is the second in two years for NASA's troubled Earth-observation programme.

Failure to release a protective covering dragged NASA's Glory mission into the Pacific.AP Photo/B. Walton/Santa Maria Times

In a serious blow to Earth observation and solar science, NASA's Glory mission crashed today shortly after lift-off.

"All indications are that the satellite and rocket are in the southern Pacific Ocean somewhere," said a visibly upset Omar Baez, NASA's launch director for the mission, at a press conference held early this morning at Vandenberg Air Force Base, California, where Glory launched shortly after 2 a.m. local time.

The failure is the second major loss for NASA's Earth-observation programme in as many years. In February 2009, NASA lost its Orbiting Carbon Observatory (OCO) — intended to track atmospheric carbon dioxide levels — in a strikingly similar incident.

Both satellites were launched on a Taurus XL rocket built by Orbital Sciences Corporation, a commercial rocket developer based in Dulles, Virginia. Both Glory and the OCO apparently suffered the same fate: the fairing, which is the protective clamshell surrounding the satellite, failed to separate from the spacecraft. The extra weight of the fairing dragged both rockets into the icy waters near Antarctica.

Telemetry data from the rocket are still being processed, but Baez told reporters that he is already sure that Glory landed at the 2009 OCO crash site: "Physics says it's likely in the same spot, or close to it," he said glumly.

Confidence blown

Glory was designed to give a global picture of the effects of airborne particles on climate, by collecting data on clouds and on the distribution and chemistry of particulate matter in the atmosphere. Without the mission, scientists will struggle to separate the various effects of dust, sulphates, black carbon and other particulates on climate change.

"A uniform data product is really key to having confidence in your models," says Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who follows rocket launches closely. "This is a real blow."

The mission also carried a solar irradiance monitor to measure the total energy output of the Sun. This does not vary by much, but changes in the amount of ultraviolet light and X-rays the Sun produces may affect atmospheric chemistry, says Jean-Yves Prado, a project scientist at the French space agency CNES in Toulouse, who works on a similar solar-monitoring mission known as PICARD.

Because solar irradiance missions are notoriously difficult to build and operate, Prado says that the Glory mission would have provided a valuable cross-check for existing satellites. It would also have ensured that there were no gaps in monitoring when existing missions end (see 'Probe keeps keen eye on Sun'). "It's a pity," he says.

Crash and burn

Engineers determined that the most likely culprit for the OCO failure in 2009 was the initiating system used to separate the fairing from the rocket body.

That original system used pyrotechnics to generate hot gas, which drove two pistons to push the fairing halves from the rocket body. In the new design, the system used pressurized cold nitrogen gas instead.

"We really felt like we had the problem nailed," said Richard Straka, deputy manager of Orbital Science's launch system group, at the press conference. Managers from Orbital Sciences who were present at the launch could not explain the apparent similarities between the Glory and OCO launch failures.

"It's not good for Orbital and not good for climate science," says McDowell. The Glory launch failure is the third out of the past four for the Taurus rocket, and raises serious questions about the programme's management, he says.

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A Taurus XL rocket was scheduled to be used in 2013 to launch the replacement to the lost OCO satellite, but Mike Luther, deputy associate administrator for science programmes at NASA, says that plan is now on hold until the investigation into the latest failure is concluded.

Orbital Science's Pegasus and Minotaur rockets use fairings and fairing-release systems that are similar to those on its Taurus rockets, says McDowell. "My guess is that this is going to turn out to be a wiring error." He adds that fairing and stage separation are among the trickiest bits of rocketry to get right.

Straka, meanwhile, says that Orbital Sciences put additional telemetry apparatus on the rocket that was used to launch Glory, and that they have already begun "crunching the data" to see if they can work out what happened. 

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