NASA's LCROSS mission went plunging into a permanently shadowed crater near the moon's south pole this morning -- an empty rocket stage, followed four minutes later by a small satellite to see if the rocket kicked up ice in the lunar soil.
Did it find any? NASA could not, at least for now, say.
"We're not going to make any claims about water, no water, whatever," said NASA's Jennifer Heldmann, who coordinated data from more than a dozen of the world's most powerful telescopes, watching as the impact happened a quarter of a million miles away.
There was one image, from the LCROSS satellite tracking the crashing rocket, showing a white flash at the impact point. But it was just a few pixels across, and so far, scientists said they did not have images of the plume of debris they had expected.
"Life is full of surprises," said Anthony Colaprete, the mission's principal investigator, at a news conference this morning. "We have to look at a lot of data."
The scientists said they had reams of data to comb through, and pictures might not tell the story. Spectrometers -- instruments that detect the chemical composition of distant objects -- may be more useful after analysis. The process, said scientists, may take months.
One scientist conceded it is possible the rocket missed any pockets of ice that might be in the crater -- or that the theory could be wrong, and there are not large amounts of ice in the soil after all.
The space agency sent LCROSS (short for Lunar CRater Observation and Sensing Satellite) to look for ice in the lunar soil -- which NASA hopes may be helpful to future astonauts trying to live long-term on the moon.
If they can prove it is there in sufficient quantities, it could be a boon to the space agency, which hopes in coming decades to build a lunar base and go on from there to Mars and the rest of the solar system. Such a base would be expensive and troublesome to supply -- but frozen water would make a big difference.
Melting the ice for drinking, washing and perhaps growing food in pressurized greenhouses would be the least of it. Water is, of course, H2O -- and can be broken down chemically to make hydrogen for fuel and oxygen for breathing.
"If we could live off the land, using this water -- if we discover it -- that would be a great benefit," said Jim Garvin, chief scientist at NASA's Goddard Space Flight Center in Maryland. "That would mean we don't have to bring it with us."
Impact came shortly after 7:3 a.m. ET on Friday, and indications were that instruments watching the crash were working properly. They included spectrometers, instruments that measure the chemical composition of the plume kicked up by the crashing rocket.
Useful data also was expected from the LCROSS satellite, flying a few hundred miles behind its Centaur booster. The satellite had four minutes to transmit its findings before it, too, hit the surface.
"If we find water there, it will change the course of exploration," said Rusty Hunt of NASA's Ames Research Center in Mountain View, Calif. "If there's water near the south pole, we'd go there."
Hunt is a flight director for LCROSS, which was launched from Florida in June. He was the hands-on manager of the mission this morning.
In 1972, the last Apollo astronauts came home from the moon, and that was that. The consensus was that the rocks they had found were dry as dust -- even more so, in fact.
But the conventional wisdom has changed.
In 1994, a military space probe called Clementine, sent to map the moon as a way of testing sensors for possible Defense Department use, found evidence of ice in the shadowed corners of craters near the moon's south pole.
In 1998 a NASA probe called Lunar Prospector was sent to confirm Clementine's findings, and as it orbited the moon it found evidence of large amounts of ice in the lunar soil.
The working theory is that comets, crashing into the moon over the eons, left tons of ice. In most places, it would have vaporized quickly. But some craters near the moon's south pole are so deep -- and the angle of sunlight is always so shallow -- that ice could have remained frozen.
The earlier probes only took indirect measurements to suggest lunar ice. But could they be right? Engineers on Earth almost salivate at the thought.
That is because NASA's current mandate, laid out by President Bush and so far backed by President Obama, is to use the moon as a base for human exploration of Mars and beyond. As part of Project Constellation, they would set up camp in their Altair landing ships.
If there is frozen water there -- H2O -- it could be used for drinking, or broken down into its components of hydrogen and oxygen for fuel, air to breathe, and myriad other uses.
LCROSS, by NASA standards, is a low-cost mission, with a fixed budget of $79 million -- a good chunk of money, but remember that the movie "Transformers: Revenge of the Fallen" has grossed about $400 million since its release in June.
There has been long debate over the merits of sending astronauts back to the moon, but if LCROSS finds water, it will make the lives of future astronauts much simpler.
"It's a pretty simple mission with profound implications," said Hunt.