Searching for Water on the Moon: UC San Diego Researchers Uncover Clues to Lunar Water's Origins

Written by Copernical Team Friday, 31 January 2025 11:14

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Los Angeles CA (SPX) Jan 30, 2025

As humanity envisions establishing a permanent presence on the moon, Mars, and beyond, the challenge of sustaining life comes down to the essentials: oxygen, food, and water. While it is well-known that water exists on the moon, pinpointing its exact locations remains a key question. Is it hidden within craters, trapped in the moon's shadowed regions, or concentrated near the poles? Answering th

Searching for Water on the Moon: UC San Diego Researchers Uncover Clues to Lunar Water's Origins
by Clarence Oxford
Los Angeles CA (SPX) Jan 30, 2025

As humanity envisions establishing a permanent presence on the moon, Mars, and beyond, the challenge of sustaining life comes down to the essentials: oxygen, food, and water. While it is well-known that water exists on the moon, pinpointing its exact locations remains a key question. Is it hidden within craters, trapped in the moon's shadowed regions, or concentrated near the poles? Answering this will provide vital information for future lunar exploration, particularly for NASA's Artemis program, which aims to eventually establish a human presence on the moon.

Researchers from the University of California, San Diego, are helping solve this puzzle, offering insights that could guide future missions, including NASA's Artemis initiative. Their findings were published in the Proceedings of the National Academy of Sciences (PNAS) in a special issue on "Water on the Moon and Mars," which also highlights Artemis I on its cover.

The team was led by Mark Thiemens, a Distinguished Professor of Chemistry and Biochemistry at UC San Diego, and his son, Maxwell Thiemens, a research fellow at Vrije Universiteit Brussel and former Scripps Institution of Oceanography student.

In 1967, Nobel laureate Harold Urey and James Arnold, both professors at UC San Diego's Department of Chemistry, were among the first to study samples from the Apollo 11 mission. Urey theorized that water could exist on the moon, especially in the permanently shadowed regions of the lunar poles. Today, scientists recognize three possible sources for the water on the moon:

1. Indigenous water, native to the moon itself

2. Water created by solar winds, where hydrogen from the sun reacts with oxygen on the moon's surface

3. Water deposited by icy comets that have collided with the lunar surface

On Earth, human civilizations often form near bodies of water, and the same logic applies to space exploration. Understanding where the moon's water comes from is crucial for determining the best locations for establishing lunar habitats.

To investigate the origin of lunar water, UC San Diego's Morgan Nunn Martinez (then a graduate student) extracted trace amounts from lunar rocks collected during the 1969 Apollo 9 mission. The process, known as "thermal release," involves heating the lunar samples to temperatures of 50, 150, and 1,000 degrees Celsius (122, 302, and 1,832 degrees Fahrenheit). Surprisingly, these rocks released significant amounts of water.

At the lower temperatures, the water molecules were weakly bound to the rocks. When the samples were heated to 1,000 degrees Celsius, more tightly bound water molecules were released, providing critical insight into the water's origins.

The released gases were then purified to isolate the oxygen, allowing the team to measure the composition of three different oxygen isotopes - atoms of oxygen that vary in neutron count and weight. This method is a form of "space forensics," where the isotopes act like fingerprints, helping scientists determine the water's origin.

The analysis revealed that the majority of the moon's water likely originates from either the moon itself or from cometary impacts. Contrary to previous assumptions, solar wind did not appear to be a significant contributor.

Maxwell Thiemens commented, "What's nice about this research is that we're using the most advanced scientific measurements and it supports common sense ideas about lunar water - much of it has been there since the beginning, and more was added by these icy comet impacts. The more complicated method of solar wind-derived water doesn't appear to have been that productive."

While the study focused primarily on the moon, the team also analyzed Martian samples. This is important because if NASA's Artemis program successfully establishes a lunar colony, it could provide a foundation for future missions to Mars, which may harbor even more water than the moon.

Mark Thiemens added, "This kind of work hasn't been done before, and we think it can provide NASA with some valuable clues about where water is located on the moon. The real goal of Artemis is to get to Mars. Our research shows that likely there is at least as much water on Mars as on the moon, if not more."

Locating water is just the first step. Extracting it in sufficient quantities from lunar rocks and soil to support human life will require significant technological advancements.

Full list of authors: Maxwell Thiemens (Vrije Universiteit Brussel), Morgan Nunn Martinez, and Mark Thiemens (UC San Diego).

This research was supported, in part, by a NASA Earth and Space Science Fellowship, a Zonta International Amelia Earhart Fellowship, and the Achievement Rewards for College Scientists Fellowship.

Research Report:Triple oxygen isotopes of lunar water unveil indigenous and cometary heritage