Marvelous moons

Lunar Prospector has instruments at the end of those graceful legs. Its body is cloaked in curving solar panels. Courtesy of NASA.

Clementine brought back sketchy evidence of water on the moon Courtesy of NASA.

  Liquid gold on the moon
POSTED 26 MARCH 1998 On March 5, NASA scientists announced the discovery of water -- good ol' H2O -- on the moon. Instead of a dusty, barren and dry satellite, our orbital companion now seems dusty, barren and wet.

Well, not exactly sopping. But in craters near the lunar poles (which can't be seen from Earth) the lunar soil apparently contains ice crystals. Anywhere else on the moon, water would be vaporized by intense sunlight and lost to space.

prospectorThe water could be useful to future explorers and makers of lunar snow cones alike. But even if the report is correct, this ice is spread across thousands of square kilometers of lunar terrain. And only one percent of the soil at best is ice, according to William Feldman of Los Alamos National Laboratory, a member of the Lunar Prospector science team.

And before you imagine astronauts eagerly sipping from a gentle spring, remember that this ice only exists because those shadows are frigid -- around 280 below zero Fahrenheit. (Our metric converter is frozen solid, but instinct sez that's worse than a windy January night in Wisconsin.)

Lunar dreams
Still, the discovery jazzed planetary scientists and starry-eyed dreamers alike. The scientists want to return to the moon for a closer look at the water. The dreamers -- we won't call them loonies -- want to set up camp on the moon and turn that ice into "Lunar Spring" bottled water and bargain-basement rocket fuel.

First things first: How do we know there's water on the moon?

oh my darlin'In 1996, a satellite called Clementine sent back some signs of water. Although the finding was controversial, in January, 1998 Lunar Prospector found hydrogen -- and presumably water -- in those shady craters, the coldest parts of the lunar surface.

Prospector is a small, cheap satellite that inaugurated NASA'S small, cheap Discovery program. Instead of launching Cadillac orbiters adorned with headlight cleaners and digital cell-fax phones, Discover's goal is boosting into orbit small, cheap satellites built from off-the-shelf parts -- ideally before the scientists who suggested them retire.

Soon after Prospector reached the moon, its neutron spectrometer began signaling the presence of hydrogen atoms in the moon's "soil." (Want to borrow a sample of lunar soil?) That's the layer of asteroid-churned junk on the moon's surface.

No bait. No switch.
Two problems: What the devil is a neutron spectrometer? And you were talking about "water." Suddenly it's "hydrogen." Is this a bait and switch?

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