Scientists at The University of New Mexico recently took part in the opening of ANGSA 73001, a drive tube lunar sample collected by NASA's Apollo 17 mission that will allow scientists to study any gases that may reside in the container as well as lunar soil samples from the 50-year-old sample.
The sample, which comprises about 800 grams (1.8 pounds) of material, was collected from a landslide deposit in the Moon's Taurus–Littrow Valley by astronauts Eugene Cernan and Harrison "Jack" Schmitt in December 1972 in a pair of 1.5-by-14-inch double drive tubes that were hammered into the surface and the lower drive tube upon extraction was placed in the core sample vacuum container (CSVC). That core preserved not just the rocks themselves but also the stratigraphy from below the surface so today's scientists can, in a laboratory, study the rock layers exactly as they existed on the Moon.
Now, scientists are focusing attention on the sealed, lower segment of the core. The temperature at the bottom of the core was incredibly cold when it was collected, which means that volatiles (substances that evaporate at normal temperatures, like water ice and carbon dioxide) might have been present. They are particularly interested in the volatiles in these samples from the equatorial regions of the Moon because they will allow future scientists studying the Artemis samples to better understand where and what volatiles might be present in those samples.
The sealed tube has been carefully stored in a protective outer vacuum tube and in an atmosphere-controlled environment at Johnson ever since. The team will examine the "water," gas, and volatile element record preserved in these specially preserved samples, the effectiveness of the sample container in keeping these samples uncorrupted, and potential container improvements. The core has been carefully stored at NASA's Johnson Space Center in Houston, Texas, since December 1972.
This work is being led by the Apollo Next Generation Sample Analysis Program (ANGSA), a science team that aims to learn more about the sample and the lunar surface in preparation for the future Artemis missions to the Moon's South Pole. UNM Research Scientist Charles "Chip" Shearer, science co-lead for ANGSA and research scientist at UNM's Institute of Meteoritics (IOM) and a research professor in the Department of Earth & Planetary Sciences, has led this effort for the past 10 years when he initially chaired a committee that provided guidance on handling lunar samples.
NASA's Ryan Zeigler, the Apollo sample curator, is overseeing the process of extracting the gas and rock. It's also Zeigler's job to properly prepare, catalog, and share the sample with others for research. "A lot of people are getting excited," said Zeigler. "University of New Mexico's Chip Shearer proposed the project over a decade ago, and for the past three years, we've had two great teams developing the unique equipment to make it possible."
The sample was opened recently at NASA's Johnson Space Center in Houston by the Astromaterials Research and Exploration Science Division (ARES), which safeguards, studies, and shares NASA's collection of extraterrestrial samples. The team systematically examined the double drive tube core over a three-week period in preparation for "opening" the tube.
"The samples were sealed on the surface of the Moon and may have preserved many characteristics of the lunar soil that could have been destroyed once returned to Earth. The other unique characteristic of this sample is that it's the only core sample that the astronauts collected that penetrated a landslide deposit." – UNM Research Scientist Charles "Chip" Shearer
On, Feb. 11, the team began the careful, months-long process to remove the sample by first opening the outer protective tube and capturing any gas inside. Zeigler and his team knew what gases should be present inside the outer container and found everything was as expected. The tube seemed to contain no lunar gas, indicating the seal on the inner sample tube was still likely intact. On Feb. 23, the team began the next step: a multi-week process of piercing the inner container and slowly gathering any lunar gases that are hopefully still inside.
"There are two unique features of these double drive tube core samples," said Shearer. "The samples were sealed on the surface of the Moon and may have preserved many characteristics of the lunar soil that could have been destroyed once returned to Earth. The other unique characteristic of this sample is that it's the only core sample that the astronauts collected that penetrated a landslide deposit."
The amount of gas expected to be present in this sealed Apollo sample is likely very low. If scientists can carefully extract these gases, they can be analyzed and identified using modern mass spectrometry technology. This technology, which has evolved to levels of extreme sensitivity in recent years, can precisely determine the mass of unknown molecules and use that data to precisely identify them. This not only makes for improved measurements but also means the collected gas can be divided into smaller portions and shared with more researchers conducting different kinds of lunar science.
The device being used to extract and collect the gas, called a manifold, was developed by Alex Meshik, Olga Pravdivtseva, and Rita Parai from Washington University in St. Louis. Francesca McDonald from the European Space Agency led a group in building the special tool to carefully pierce the container holding the lunar sample without letting any gas escape. Together, they've created and rigorously tested a one-of-a-kind system to collect the extremely precious material – gas and solid – that is sealed inside the containers.
"We'll do some analyses to see if we can get fingerprints of what gases are there that we can attribute to the moon, or the processing itself and the nitrogen glove boxes, or with the terrestrial atmosphere," said Shearer. "All of our evidence suggests that there's no contamination at all from the threshold atmosphere. There's no oxygen in the gases that we sampled. There is some hydrogen and some nitrogen, so I don't think we've had terrestrial contamination or crew cab contamination, but what we don't know is if some of the nitrogen from these glove boxes leaked into various parts of the container."
In about two weeks, the samples will be ready to go to various labs for testing including UNM and the University of Washington, St. Louis (Mo.). That's when Zach Sharp, director of the UNM's Center for Stable Isotopes and a Distinguished Professor in the Earth & Planetary Sciences (E&PS) Department, will have the opportunity to study UNM's sample. His isotope research includes high temperature igneous and metamorphic petrology, planetary sciences, including studies of Moon and Mars, as well as low-temperature studies of soil carbonates, water and atmospheric water vapor.
"We'll connect a little tube with a hermetically-sealed valve on one end and hook that up to our mass spectrometer and we'll scan through all the different masses and determine the size of the peaks and figure out what gas is there and what the abundance is," Sharp said. "It's mostly going to be nitrogen, so we'll see the nitrogen ice ratios."
After the gas extraction process is finished, the ARES team will prepare to carefully remove the soil and rocks from their container, likely later this spring.
"The main important thing we're going to do is to measure the hydrogen," said Sharp. "Hydrogen is the closest thing you get to water, so I would say of all the analyses that we can make this is arguably the most important, especially if people are talking about going to the moon and colonizing it someday. Water is critical and they're going to get it from the moon. It's an important measurement, but it won't be on this gas sample. It will probably be on the solid rock which we will also analyze later this spring."
Since the Apollo era, all samples that were returned to Earth have been carefully stored in the laboratory to preserve them for future generations. Most samples have been well studied, and many are the subject of ongoing research. However, NASA also made the decision to keep some samples completely untouched as an investment in the future, allowing them to be analyzed with more advanced technologies as they are developed.
These include samples that remained sealed in their original containers, as well as some stored under special conditions, all intended to be opened and analyzed with more advanced analytical technologies that were unavailable during Apollo. This core along with the other samples collected during the Apollo Program represents the "crown jewels" of the United States and its space exploration program.
"I was told by the curator at the time that there were some lunar samples that have never been looked at all, that were in their original containers or were frozen samples for 50 years, so this rather piqued my interest," said Shearer. "At the time (2010), there didn't appear to be in the near future, any possibility of a lunar sample return so I came up with this concept of examining these unknown samples that were returned like we would in a low-cost robotic sample return mission. Through a lot of persistence and constantly going to the NASA headquarters to discuss this potential project with them, we eventually moved forward and started this project and got the funding for it four years ago."
The New Mexico Space Grant Consortium, a statewide collaboration with industry, government and academic partners, provided seed money in the early stages of the development of this project. The Consortium has supported various projects since its creation in 1989.
Additional members of the UNM's Consortium for the Advanced Analysis of Apollo Samples (CAAAS) include Adrian Brearley, Michael Cato, Steve Simon, Zach Sharp and Karen Ziegler, all are members of the IOM and E&PS. Schmitt, from Albuquerque, is actively involved in UNM's science team and was the lone geologist among the Apollo astronauts and lunar module pilot of Apollo 17, which collected sample 73001. James Papike, emeritus director of UNM's Institute of Meteoritics, now deceased, was also a member of the CAAAS team.
"One thing that I think is kind of important to add, from the UNM point of view and the New Mexico point of view, is that we have a lot of infrastructure and talent to compete in space and be part of the Artemis program," said Shearer. "I think this program essentially shows that we are involved in space exploration and illustrates that having UNM and the state, both the private sector and the university sector, integrate and organize more, I think New Mexico could compete better overall in the exploration of the space."
"Understanding the geologic history and evolution of the Moon samples at the Apollo landing sites will help us prepare for the types of samples that may be encountered during Artemis," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate in Washington. "Artemis aims to bring back cold and sealed samples from near the lunar South Pole. This is an exciting learning opportunity to understand the tools needed for collecting and transporting these samples, for analyzing them, and for storing them on Earth for future generations of scientists."
