[Reading Science] The Dry Moon, Where Did All That Water Come From?

Chinese Academy of Sciences Announces Lunar Regolith Analysis Results on 27th Last Month
Water Found in Glass Beads in Soil, Estimated Total 270 Billion Tons
Water Formed as Solar Wind Hits Silicon Oxide
Stored in Glass Beads Created by Meteorite Impacts
Expected to Accelerate Moon Exploration, "First Country to Arrive Will Claim It"

Recently, China announced a research finding that an astonishing 270 billion tons of water exist on the Moon, sparking great interest. How could such a large amount of water be generated and preserved on the Moon, which was thought to have only dry surface soil due to its thin atmosphere and weak gravity? Scientists attribute this to the presence of solar wind. This finding is seen as further proof that humanity can use the Moon as a base for space exploration, including the construction of manned bases. It has also set the stage for intensified lunar development competition among major powers such as the United States and China. There are calls for South Korea to accelerate its lunar exploration efforts, including the planned launch of a landing probe targeting 2032.

Origin of Lunar Water Revealed

The Chinese Academy of Sciences (CSA) published a remarkable research result on the 27th of last month in the international journal Nature Geoscience. By analyzing about 1.7 kg of lunar rocks and surface soil collected by the Chang'e-5 lunar lander on December 1, 2020, they found numerous tiny glass beads less than 1 mm in diameter formed over billions of years, within which water molecules were detected. Based on this, the CSA estimated that as much as 270 billion tons of water could exist across the entire Moon?enough to cover the lunar surface with a 12-meter-thick layer.

The CSA’s analysis of lunar surface soil is considered a clue to the origin of how water was generated and stored on the otherwise dry Moon. The Moon has been completely dry for billions of years. Even if comets or asteroids containing ice collided and introduced water, it would quickly evaporate into space. However, water formed by hydrogen ions carried by the solar wind colliding with the lunar soil was different. Kyungja Kim, head of the Space Resource Development Center at the Korea Institute of Geoscience and Mineral Resources (KIGAM), explained, "Solar wind consists of protons, i.e., hydrogen ions (H+), which react with iron oxide (Fe2O3) in the lunar soil upon impact to create water (H2O), while iron (Fe) is released." She added, "The orange-colored soil seen during Apollo 17’s last manned mission is evidence of iron oxide mixed in the soil."

The lunar surface heats up to 123 degrees Celsius during the day, causing water to evaporate, but at night it cools down to as low as minus 233 degrees Celsius, allowing some of the vaporized water to seep into and cool within the soil. Particularly, the heat energy generated by meteorite impacts melts the silica components in the lunar soil, forming tiny glass beads that trap and preserve water inside. The CSA stated, "This study not only reveals the mechanism of water formation on the Moon but also suggests that water created by solar wind can be stored in impact-generated glass beads and released into space on the lunar surface and other planets in the solar system." They added, "This could serve as a means of water extraction for future lunar development and could also be used for rocket fuel production."

However, some argue that the CSA’s announcement is not entirely new. The Moon’s appearance first revealed to humanity through Apollo missions from 1969 to 1972 was like a desert. Yet, the presence of water on the Moon is not new news. NASA’s lunar orbiters had already found evidence of water in permanently shadowed craters at the Moon’s north pole in the 1990s. In the 2000s, advanced analyses of lunar samples collected during Apollo missions revealed the presence and origin of water. In 2013, a research team from Michigan State University discovered traces of water within crystals in rock samples brought back by Apollo 15 in 1971.

The team analyzed grains of the famous iron-bearing plagioclase feldspar samples 15415 and 60015, known as the "Genesis Rock," using Fourier Transform Infrared Spectroscopy (FTIR) and found 6 ppm of water content. Although not in liquid form, they detected hydroxyl groups (OH), which consist of one hydrogen atom and one oxygen atom and are related to water. Notably, the samples analyzed were collected from the lunar highlands, believed to have formed the Moon’s earliest crust during its formation. This indicates that water existed from the Moon’s early formation. In 2008, further analysis of Apollo lunar samples using ion microprobes detected hydrogen originally present, confirming the presence of hydroxyl groups and thus water.

In South Korea, KIGAM, which is researching lunar resource extraction technology, has confirmed that when protons collide with oxides such as silicon dioxide, ions exchange to form water. Senior researcher Kim said, "NASA and others had previously confirmed that heating lunar samples brought back by Apollo missions to 700?1400 degrees Celsius releases vaporized water and helium gas, and Apollo beads are well-known; thus, the CSA’s findings are not new." He added, "We also studied how protons from solar wind hitting the lunar surface generate volatile substances." However, he noted, "The significance lies in the CSA’s use of advanced technology to electronically image the water trapped inside glass beads, allowing people to see and appreciate it."

What Is Lunar Water Used For?

Water is fundamental to life, including human life. Beyond drinking and daily use, water can be electrolyzed into hydrogen and oxygen to supply fuel and life support for space bases and spacecraft. Humanity is already accelerating the construction of manned lunar bases based on the assumption that large amounts of water exist on the Moon. The European Space Agency (ESA) plans to build a lunar base called "Moon Village" by 2040. It will house about 100 people and serve as an advanced base for deep space exploration. ESA plans to send an initial team of 6 to 10 people in the 2030s, gradually expanding to 100 residents in the 2040s and 1,000 in the 2050s. The base will be built near the lunar south pole, where underground ice will be melted for drinking water, daily use, and rocket fuel.

The United States also declared the resumption of lunar exploration in 2021, aiming to build a manned base. They plan to construct the "Deep Space Gateway," where astronauts will live, conduct exploration, and refuel. Initially, about six people will reside there, with accommodations, laboratories, communication facilities, water electrolysis systems, and spacecraft landing and takeoff centers. Prior to this, the U.S. plans to launch "Artemis 3" after 2025, marking the first manned lunar landing mission in over 50 years since Apollo 17 in 1972.

South Korea’s first lunar probe, "Danuri," which arrived in lunar orbit last December, has been extensively surveying the Moon since this year using six scientific instruments. Using magnetic field and gamma-ray detectors, a high-resolution camera, and a wide-field polarization camera, it is thoroughly investigating the Moon’s structure and surface. Through the first space internet transmission experiment, music by BTS was broadcast via radio waves in space. Danuri also carries NASA’s ShadowCam, a camera designed for permanently shadowed regions, helping to scout the Artemis 3 landing site near the lunar south pole. South Korea plans to attempt a lunar landing mission in 2032. The country intends to upgrade its first developed space launch vehicle, Nuri, to more than triple its current performance and send a 1.8-ton-class lander to the Moon for exploration. Meanwhile, other major space technology countries such as Russia, China, Japan, India, and the United Arab Emirates (UAE) are also actively investing in lunar exploration.

The Country That Goes First Wins

Why are major countries around the world so eager to explore the Moon? Agencies like NASA often cite the search for extraterrestrial life or intellectual contributions to humanity through scientific inquiry as their official reasons, despite astronomical budgets. Indeed, treaties such as the 1960s United Nations Outer Space Treaty and the Moon Treaty designate space as a peaceful domain and common heritage of mankind, prohibiting exclusive possession. However, reality is quite different. The country that claims territory first gains everything and dominates space supremacy. Whether on the Moon or Mars, the first country to arrive can occupy resource-rich areas, build bases, and reap economic benefits with no way to prevent it.

Already, the United States recognized private space companies’ ownership of space mining resources in 2015. In 2018, it announced a new space policy declaring space as a core pillar of future economy, resource exploration, and national security. Since then, it has established and significantly strengthened the Space Force in 2019. Luxembourg enacted similar legislation in 2021 to promote space mining. Russia has also established a Space Force and is developing new space weapons, while China has emerged as the main rival by launching its own space station to counter the U.S. Japan is strengthening its space defense capabilities by reorganizing its Air Self-Defense Force into an Air and Space Self-Defense Force. At the Space Debate Forum held last December in Abu Dhabi, UAE, futurist George Freeman predicted, "The Third World War could occur in space."