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Not your ordinary space rock. (NASA image)

In 1982, the idea that a chunk of rock could be hurled from the moon to Earth by a lunar impact was considered pretty far out. For one thing, wouldn’t such a massive, high-energy explosion destroy the evidence by turning the excavated rocks to glass? Besides, meteorites were well known to come from small bodies like asteroids.

On January 18 of that year, a pair of geologists hunting for meteorites on the icy ground in Antarctica’s Allan Hills region came across a greenish-tan sample they tagged as ALHA81005. It was the last stone they found that day before returning to camp—in fact, the last one of 373 specimens collected during the 1981-82 field season.

Back in the lab at NASA’s Johnson Space Center, scientists immediately recognized the rock as unusual. When a thin section was sent to the Smithsonian’s Brian Mason, an internationally known expert on lunar geochemistry, he commented in a scientific bulletin: “Some of the clasts resemble the anorthositic clasts described from lunar rocks.” Mason, who died last week at the age of 92, was the first to make a connection between a meteorite found on Earth and the samples returned by the Apollo astronauts a decade earlier.

Later analysis confirmed Mason’s suspicion. The types of glass particles in the meteorite matched those in lunar rocks exactly, as did the ratios of iron and manganese. Impact experts even came up with an explanation for how ALHA81005 got here in one piece. It turns out that rocks lying close to the moon’s surface would be spared the worst shock effects in an impact. In fact, the lunar meteorite was no more damaged than other rocks Apollo astronauts had picked off the ground, even though it blasted off the moon at a speed exceeding 1.5 miles per second (lunar escape velocity).

When scientists presented these and other results at a conference more than a year later, “No one in the large crowd even stood to object to the provocative claim,” according to Science magazine. “The psychological barrier to the idea that meteorites can originate on large bodies [including Mars] had been broken.”

Today’s offering is a post-Thanksgiving smorgasbord of stories (okay, I’ll stop with the alliteration).

• First, a lovely NASA video of an aurora shimmering above Saturn, with commentary by Caltech planetary scientist Andy Ingersoll, who’s been exploring the outer solar system since the Pioneer 10 and 11 missions of the 1970s:

• Next, a Russian team enters the Google Lunar X-Prize race with a rover called Selenokhod. The robot’s much larger ancestor, Lunokhod-3 (below), is now in a museum at NPO Lavochkin, the company that built it back in the 1960s.

• Finally, a fascinating Associated Press story about the long, involved search for the remains of U.S. Navy pilot Scott Speicher, who was shot down during the Gulf War, and whose remains were only recovered last summer.

See? There was a plume (the fan-shaped smudge) after all. (Photo: NASA/ LCROSS Team)

Congratulations and apologies are due. The LCROSS team, who endured much grumbling  from Internet viewers after last month’s crash into the moon failed to produce a big visible plume, is reporting what they say is clear evidence of water in a lunar crater. Not just a thimbleful, either—at least 24 gallons, and probably more, from a crater 20 to 30 meters wide. The spectral signature from two different instruments is “very real,” said a smiling principal investigator Anthony Colaprete.

The results from LCROSS lend credence to the idea that the rest of the hydrogen detected a decade ago at the moon’s poles is water ice, too, according to Greg Delory, a researcher at the University of California at Berkeley. Read about the LCROSS results here.

While scientists on the LCROSS mission puzzle over why none of the world’s telescopes apparently saw squat during last week’s much-ballyhooed lunar impact (although it now appears the spacecraft did), here’s a happier story.

View from the Lunar Reconnaissance Orbiter (Photo: NASA/GSFC/Arizona State University)

The Lunar Reconnaissance Orbiter recently took this lonely photo of the Surveyor 1 spacecraft sitting on the moon’s surface, exactly where it touched down 43 years ago.

Surveyor 1, in case you’ve forgotten, was the first U.S. spacecraft to make a soft landing on another world, on June 2, 1966. The Soviet Luna 9 mission had done the same thing four months earlier, and had sent back a couple dozen pictures of its surroundings—humanity’s first look at the moon’s surface, after centuries of wondering.

Surveyor, though, was far more sophisticated than Luna 9, and returned 11,000 photos (see the gallery below). Nobody was more surprised at its success than the people who built it. Before launch, the newspapers had been full of stories about Surveyor’s budget problems, delays, and management squabbles between NASA headquarters, the Jet Propulsion Laboratory, and Hughes Aircraft, which built the lander for JPL.

On landing day, none of that mattered. The thing worked perfectly.

Oran Nicks, who headed NASA’s lunar and planetary program at the time, was in the control room at JPL. He later recalled, “I was prepared for the worst as telemetry reports came in.” When the craft touched down, “I could hardly believe it, but then, before long, the first pixels of a TV frame showed the footpad on the surface.”

Among those who had doubted Surveyor’s chances of success was Max Faget, the designer of the Mercury capsule, who at the time was working on the Apollo program at NASA’s Manned Space Center in Houston. Faget had bad-mouthed the JPL robot lander on more than one occasion, and had told an influential Congressman that it wasn’t necessary as a precursor to Apollo’s manned landings. After Surveyor 1 touched down safely, Nicks recalled, “Max called me at NASA Headquarters to congratulate us and to say that he hadn’t believed we could bring off an unmanned landing, especially not on the first try. Though we reveled in Max’s ‘eating crow,’ we respected him greatly and took his words as high praise for our mission’s work.”

In fact, Surveyor 1 showed that the Apollo landings were possible, and that a three-legged lander wouldn’t sink in deep lunar dust, as a few alarmists had feared. The news and the photos got front page play, and it seemed in June 1966 that the Americans had pulled ahead of the Soviets in their race to the moon.

William Pickering, who was then the director of JPL, told an interviewer years later, “I felt the Apollo people should have been more interested in [Surveyor] than they were, but they said ‘Good landing,’ that’s all.”

Everyone knew that Apollo was NASA’s headline act, and that the Surveyor robots (four more landed on the moon between 1966 and 1968) were just bit players. But for a couple of years JPL had the moon to itself, and its engineers couldn’t help feeling smug. Recalled Pickering, “We were strongly tempted to put a sign on Surveyor that said, ‘Follow me,’ but we didn’t ever do it.”

An unsuspecting Cabeus Crater, in LCROSS's crosshairs. (Photo: B.Grieger, B.H. Foing & ESA/SMART-1/ AMIE team)

Friendly warning: Do not be in the moon’s Cabeus Crater tomorrow morning. At 7:31 eastern time, a giant, two-and-a-half ton empty rocket stage will come crashing down from the sky at 1.5 miles a second. Four minutes later, another, smaller spacecraft will hit near the same spot.

What the…? Ahh, it’s just NASA scientists looking for water again.

The Lunar CRater and Observation Satellite (LCROSS) and its Centaur rocket stage will smash into the moon so scientists can inspect the material that flies up for the spectral signature of water. Some 350 tons of debris from the Centaur impact is expected to rise miles above the lunar surface. The smaller LCROSS spacecraft will spend its final minutes flying through the spray, searching for water, before it, too, crashes into the moon. Then a variety of Earth-based telescopes will scrutinize that debris.

A few thoughts about tomorrow’s impact:

• The advertised purpose of the experiment is to settle once and for all whether there’s water ice in permanently shadowed “cold traps” near the lunar poles. How likely is LCROSS to put the matter to rest? After all, the Lunar Prospector spacecraft was sent smashing into a crater very close to Cabeus 10 years ago, for this very purpose, and saw nothing. But that experiment, a last-minute add-on to the main mission, was always given low odds of success. LCROSS was designed from the start to observe an impact with spectrometers that can detect water. The Centaur is a much bigger impactor, coming in at a steeper angle—which means a lot more energy will be delivered to the target, under much better observing conditions. That makes it more likely we’ll see something this time. But hitting the right patch of ice, in the right crater, under the right viewing conditions, is trickier than it sounds. So if LCROSS finds no water, the scientific argument is likely to continue. There will always be another place to look.

• Don’t expect a big, dramatic explosion. Even though NASA has invited the public to watch and report what they see, this is not a viewer-friendly event. The impact happens after sunrise in the eastern U.S.—bad luck, but lighting conditions at the moon were more important. The visible flash will last only a tenth of a second (although the rising plume of debris should appear for half a minute). And you’ll need at least a 10-inch telescope to see anything, even the barest smudge, which rules out all but serious amateur astronomers. “The best place to observe it is online,” says LCROSS project scientist Anthony Colaprete.

• Still, LCROSS is cool, and not just in the SCTV “blow it up real good” sense. The final pictures from the spacecraft as it kamikazes into the moon will be fun to compare to the Ranger photos from the 1960s.

• By the way, here’s what a crash site on the moon looks like. (The picture was just released today from LCROSS’s “parent spacecraft,” the Lunar Reconnaissance Orbiter.)