Sealed for 50 years, a rare Apollo lunar sample will have its opening day

In 1972, when geologist and Apollo 17 astronaut Harrison Schmitt spotted an unusual patch of orange dirt on the moon, he knew it was special, but he wasn’t sure exactly why. “Until it was possible to look at this material in the lab in high resolution and analyze it, we didn’t know we had found a deposit of volcanic ash,” he says.

Fifty years later, Schmitt is still unaware of all the discoveries his mission will bring. This is because researchers from Apollo Next Generation Sample Analysis (ANGSA) Program only recently begin to study lunar samples that had been preserved for future scientists. Their projects aim to answer crucial questions about the moon’s past and, like the Artemis program is preparing for launch in the next few years, the future of lunar exploration.

Perfectly preserved

Sample of Apollo 17 73001, which was collected from a pile of debris deposited by a lunar landslide, will be opened for the first time in the coming weeks, said ANGSA researcher Charles Shearer, a researcher at the University of New Mexico and Visiting Scholar at the Lunar and Planetary Institute. This sample was stored in a Core Sample Vacuum Container (CSVC), an elaborate hermetic device whose penetration was traced for over a year. Sample 73001 is particularly valuable because it was sealed in such pristine condition, Shearer says. “Many other Apollo samples may have had varying amounts of contamination from Earth, so we are losing some of the lunar footprint,” he says.

Schmitt, who is actively involved in the ANGSA program, has “admiration for the people who 50 years ago decided to save some of the samples in anticipation of the significant evolution of technology over time. time”. Using modern tools to analyze 73001 will provide both insight and experience in handling lunar samples that will benefit future missions, he says.

Schmitt and Shearer will help measure the lunar volatiles of 73001 – easily vaporizable chemical elements that are embedded in the moon’s soil. Using a relatively new technique that identifies each substance in a material by its mass, the team can measure volatile elements and additional compounds that decay over time in the sample. Collectively, this data provides clues to when and how the landslide happened – for example, whether it was caused by a seismic event or an impact. Solving the mystery of the landslide could also help predict the safety of human settlements on the Moon, Shearer said. “Will there be tectonic or earthquake-related activities that could threaten human activities on the Moon? ” he says. “Maybe that will shed some light on that.”

look within

Researchers also want to understand how lunar volatiles can be used as a resource to support human presence on the moon. “In the past, when Apollo went to the moon, we took everything with us,” Shearer explains. Eventually, however, astronauts may be able to “partially live off the land” as they explore and even venture beyond the moon, he says. For example, hydrogen and oxygen serve as the building blocks of water, and hydrogen and a light version of helium could be used as a source of rocket fuel to power further space travel.

Another ANGSA team is led by Darby Dyar, a professor of astronomy at Mount Holyoke College who has studied orange soil sample as a graduate student. As a researcher at ANGSA, she is characterizing volcanic glass beads in other samples to better understand the composition of the lunar interior. These pyroclastic glasses, which are smaller than a grain of salt and make up about 20% of the moon’s soil, erupt from the lunar interior during volcanic eruptions. “It’s like drilling into the moon,” says Dyar. “Tiny glass samples, but a giant scientific impact.”

Dyar examines the water and oxygen content of the glass beads as a record of the environment of the lunar interior. Work by Dyar and other researchers suggests that the moon’s interior is not dry and oxygen-free as long assumed, challenging the scientific understanding of moon formation. “We’re sort of going back through previous misconceptions about the lunar interior,” she says.

While ideally volcanic glass perfectly captures the conditions of the lunar interior, gas can seep into or out of the bead as it is expelled. To account for this effect, Dyar and his team take measurements at defined increments on the bead’s surface, generating a map showing all the gradients that developed during cooling. Instruments with this degree of spatial resolution were not available when Dyar began his research. “New technologies allow me to answer a question that I personally asked 40 years ago,” she says.

Likewise, the electronic state of the metal atoms in the bead, which provides a measure of oxygen, can change after the eruption. Charged particles from the solar wind could interact with glass on the moon’s surface, or oxygen on Earth could react with the bead after it returns from space. Analyzing samples like 73001 that were collected from deeper in the lunar interior and stored in preservation gear can help identify transformations due to exposure to the lunar surface or Earth, Dyar says.

This comparison of different storage methods provides valuable information for the return to the moon, says James Head, professor of geological and earth, environmental and planetary sciences at Brown University, who does not part of the ANGSA program. “Are we designing these sample containers correctly? How can we best design the ones that will be used in Artemis to make sure they are as perfect as possible?” he says.

Additionally, by piecing together the various lunar processes that left their mark on these samples, ANGSA’s research helps complete the picture of the moon’s history and evolution, Head said. “Each approach, like landslides and pyroclastic glasses, will fill in a small piece of the puzzle,” he says.

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