NASA Spacecraft May Have Discovered Water on MoonBy K.C. Cole
Los Angeles Times
MOUNTAIN VIEW, Calif
A NASA spacecraft has discovered what appears to be ample amounts of water on the moon - suggesting the specter of moon colonies, complete with refueling bases for solar system exploration.
Scientists at the National Aeronautics and Space Administration's Ames Research Center, the human power behind the discovery, were ecstatic over the dramatic data sent from the Lunar Prospector spacecraft, which is orbiting 60 miles above the moon. "It's a wish come true," said William Feldman, co-investigator on several instruments carried by the spacecraft.
"I can hardly contain my joy," Scott Hubbard, mission manager at Ames, said Thursday at a news conference.
While the water is frozen into ice crystals sprinkled sparsely in the frigid north and south poles of the moon, its potential for boosting space exploration within the solar system is enormous. Mainly, it means that astronauts could distill moon water into liquid oxygen and liquid hydrogen fuel - "like making moonshine," said principle investigator Alan Binder - providing energy for a return trip without carrying fuel from Earth.
"For the first time, we can go to another planetary body and fuel up," he said.
Moreover, the water - tentatively estimated at between 10 million and 300 million tons - could be used to support permanent space colonies. "That's an awful lot of water," said Binder. "What it means is that human life can expand to the moon."
Such a giant step would not come easily, however. For one thing, the ice crystals probably lie deep inside dark craters in the moon's coldest crevices - areas with permanent temperatures well below minus 200 degrees Fahrenheit. "One problem is getting machinery to work at such low temperatures," said Binder.
Another obstacle is convincing the public to fund such a project. As Binder pointed out, plans were already afoot to put a science base on the moon after the Apollo landings 25 years ago. "If we'd wanted to, we could already be there," he said. "It's a matter of interest and priorities."
Lunar Prospector did not directly observe water molecules, or even its component atoms - two hydrogens for each oxygen. Instead, one of the six instruments on board the 4-foot long, 633-pound craft measured ratios of nuclear particles called neutrons moving at different energies.
Since neutrons pack the same mass as hydrogen nuclei, a neutron colliding with hydrogen would slow down abruptly, like a billiard ball hitting another billiard ball of the same size. By measuring the relative amounts of slow neutrons to faster ones, the researchers deduced that they saw the distinct signature of hydrogen, suggestive of water.
In order to be 100 percent certain it is water, Binder conceded, robots would have to land on the moon's surface, scoop up soil samples, heat them up and see if water evaporates off. Still, he said he was certain enough of the results to bet his house on them.
"We have found water at both lunar poles," he said. Exactly how much water, however, is still in question, although there appears to be twice as much at the north pole as at the south.
The findings, presented at Thursday's news briefing, were the first from the Lunar Prospector, which has been orbiting the moon for nearly two months.
Researchers are still in the process of analyzing the first month's worth of data. Until two weeks ago, said Binder, they were convinced that there was no water on the moon. But after collecting more data and learning to understand their instruments better, the scientists came to a quite different conclusion.
If the current interpretation is correct, there could be enough water on the moon to sustain thousands of people for a hundred years.
Naturally bone dry, the moon got its water, scientists think, from comets that crashed into its surface over the past 2 billion years. Most of that water immediately evaporated into space. The moon's gravity is too puny to hold onto an atmosphere that could contain water.
Apollo astronauts, who landed near the moon's equator, brought back moon rocks bearing absolutely no signs of water.
However, water molecules that somehow hopped over the dry surface to land in permanently shadowed craters in the lunar poles could have stayed and stuck.
Pinning down exactly which craters hold the ice will have to wait until the end of the mission, when the Lunar Prospector will lower its orbit for a closer look. For now, the scientists are looking at "a huge area," said Binder, about a hundred miles across. "We will not be able to isolate individual craters until the extended mission."