After 50 years, Apollo’s moon rocks still have much to give
Some samples brought back by the moon-landing missions have yet to be opened. Richard A Lovett reports.
The world may be fast approaching the fiftieth anniversary of Apollo 11’s 1969 flight to the moon, but the samples brought back by it and NASA’s five subsequent landings remain fresh and exciting, scientists say.
The six missions brought back 381 kilograms of material, but NASA has been chary about doling them out for research, preserving much of its moon-rock archive for the development of analytical methods more capable than those possible when the samples were collected.
Advances in knowledge have also allowed today’s lunar scientists to examine the rocks with a more detailed understanding of the information they are trying to pry out of them.
For example, remote sensing and geological mapping of the moon has helped put the Apollo samples in perspective, says Charles Shearer of the University of New Mexico.
Shearer gave a detailed rundown on the possibilities inherent in the rocks last week at the Lunar and Planetary Science Conference in The Woodlands, Texas, US.
This allows scientists to reexamine previously studied samples with greater understanding of the conditions under which they formed.
“We continue to see new information by looking at Apollo samples really carefully,” adds Juliana Gross, of Rutgers University, New Jersey, US.
For example, she says, studies of these samples have found that not everything in them is originally from the moon.
A recent study revealed that one of Apollo’s moon rocks contained a pebble that appears to be a four-billion-year-old chip blasted off the Earth’s surface, making it one of the oldest Earth rocks ever collected.
Other moon rocks have also proven to contain other “exogenic” fragments from other sources, Gross says.
“[Moon rocks] are not only giving us information about the moon itself, but also about the material that was delivered to the Earth/moon system,” she says.
This helps reveal the history not only of the moon, but the entire solar system.
“New and higher precision techniques will continue to reveal more information,” she adds.
Already, Gross says, it’s possible to look into the history of a single grain of a lunar rock and see how its crystalline structure has been disrupted by ancient shocks — something that can be used to trace the impact history of the landscape where the rock formed.
It’s also now possible to study magnetic signatures in the grains in sufficient detail to learn about the state of the early lunar core and its magnetic dynamo.
What this means, says Shearer, is that after 50 years, “we still have ‘new’ Apollo samples to examine now and for future generations”.
And that’s just the beginning. There even exist samples that were sealed on the moon, returned to Earth ... and never opened.
This summer, Shearer notes, a project called the Apollo Next Generation Sample Analysis program intends to open one of them.
Precise scheduling is still uncertain, but funding has been approved, and once the scientists on the team are all in agreement and final approval is granted by the Astromaterials Acquisition and Curation Office at NASA’s Johnson Space Centre in Houston, it will probably proceed sometime this summer, right around the half-century anniversary of Apollo 11.
The material comes from the final mission in the series, Apollo 17, which landed in December 1972. It is a core sample, obtained by pounding a collection tube into the lunar surface above a suspected fault line that might have allowed gas from deeper down to percolate upward.
The tube’s container had a special indium-silver cap that, the 1972 engineers hoped, would be able to seal the stuff in its pristine state long enough for analytical methods to evolve to the point where it could be properly studied.
That is, until now.
“One should maybe consider this a new mission to the moon,” Shearer says.
The outcome will depend partly on how well NASA’s indium/silver cap worked, and partly on whether there ever were volatiles in the sample.
But whatever it teaches us about the Moon, it will also help us understand how best to handle (and dole out) samples from other sample-return missions, whether they be to the asteroids (link my story), returns to the Moon, or a long-dreamed-of sample-return mission to Mars.
“These samples truly are the gift that keeps on giving,” says Shearer.