Blast was like a sea of tranquility

WASHINGTON - For those seeking something scintillating, the moon thud was a dud.

NASA's LCROSS mission yesterday was a scientific success, according to a top agency official, but it was anticlimactic for those watching the Internet feed or attending special viewings at the Newseum in downtown Washington or at the Ames Research Center in Mountain View, Calif. The moon didn't blow up - or even flinch, as far as anyone could see.

The mission sent a rocket booster crashing into a shadowy crater at the moon's south pole. A shepherding spacecraft obtained images of the impact and then, as planned, crashed near the same spot.

NASA's black-and-white imagery showed the crater looming larger and larger as the spacecraft descended. But when the booster slammed into the moon, in the darkness of the crater, there was no obvious sign of a plume of dust - or pulverized water ice, which is what NASA was hoping to find. Instead, the video feed went completely white.

That wasn't a malfunction, said Benjamin Neumann, director of NASA's Advanced Capabilities Division. It was more like a blinding flash.

"It was so bright, we saw white," Neumann said. "The instruments will have this data. It's a lot of energy, so it turns it to heat."

NASA scientists have said it will take a couple of weeks to analyze the data and determine whether the crater harbored ice. The LCROSS spacecraft was equipped with nine instruments; an additional seven instruments are on board a NASA spacecraft in lunar orbit. The impacts were also observed by telescopes on Earth and in space, including the Hubble Space Telescope.

The Lunar Crater Observation and Sensing Satellite launched in June with the goal of finding out whether water ice might lie hidden at the bottom of polar craters on the moon that haven't seen sunlight in billions of years.

That had been an open question since the Lunar Prospector mission detected large quantities of hydrogen at the south pole in 1998. Hydrogen is a marker for water. Scientists hypothesized that the water might have been delivered to the moon the same way it accumulated on Earth, through millions of years of bombardment by water-bearing comets and meteorites.

The LCROSS spacecraft was designed to steer the Centaur rocket that helped launch it into a crater called Cabeus, where especially large amounts of hydrogen had been measured.

After the Centaur crashed, the spacecraft was supposed to fly through the debris kicked up by the SUV-sized rocket. The spacecraft's nine instruments were designed to detect the presence of water, if it's there.

The mission appeared to go according to plan, except that no plume showed up on camera. Even with that disappointment, many people in the crowd watching the event applauded.

Other observers may have been disappointed, but Lindsey Pollock, 24, a graphic designer from Mountain View, was delighted. "You could see the camera getting closer and closer to the moon," she said.

Mike Bicay, the director of science at Ames, said it was possible one or more of those instruments was able to see the plume that failed to appear on-screen yesterday.

"We need to go back and look at the data," said Anthony Colaprete, principal investigator of the LCROSS mission. "I see something in the spectrometer, but I can't say anything more right now."

"This is what exploration is," said Michael Wargo, chief lunar scientist at NASA headquarters in Washington.

Dud or not, see more

at NASA's Web site via http://go.philly.com/nasaEndText