There are no reservoirs on the moon as we know it from Earth. However, according to the latest findings of NASA scientists, there may be more water on the moon than previously estimated. A team led by Casey Honniball of NASA’s Goddard Space Flight Center in Maryland discovered water molecules on the lunar surface, trapped in mineral grains or between their debris.
At the same time, another team determined that the Moon has an area of approximately 40,000 square kilometers of solid shadow that could potentially hide “pockets” of water in the form of ice.
NASA announced the latest discoveries regarding water on the moon during a Monday press conference.
Water in the Clavius crater
NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) has confirmed the presence of water on the Sun’s side of the Moon, Nature Astronomy reported on Monday.
SOFIA is a joint project of NASA and the German Center for Aviation and Astronautics. Equipped with a telescope approximately 270 centimeters in diameter, the modified Boeing 747SP enables astronomers to study the solar system and more in a way that is not possible with ground-based telescopes. Flying over 13 kilometers, the plane rises above the atmospheric water vapor (or rather 99 percent of that vapor) to get a clearer infrared picture of the universe.
Using its Faint Object infrared camera connected to the telescope (FORCAST), SOFIA was able to capture a water-particle-specific wavelength (6.1 microns) and discovered it in the sunlit lunar Clavius crater.
Clavius, which is located in the southern hemisphere of the moon, is one of the largest craters visible from Earth. Earlier observations of the lunar surface have detected some form of hydrogen, but have not been able to distinguish water from its resemblance to hydroxyl (OH). Data from Clavius revealed the presence of water at concentrations ranging from 100 to 412 parts per million – roughly just over 1/3 of a liter per cubic meter of soil on the lunar surface.
For comparison, there is 100 times more water in the sand of the Sahara than in the lunar soil studied by SOFIA. The discovery raises new questions about how water is produced and persists on the moon’s harsh, airless surface. According to experts, water can be present on the surface of the moon not only in cold, shady places.
“We had indications that water might be present on the sunlit side of the moon,” said Paul Hertz, director of the Astrophysics Division at NASA’s Directorate of Science Missions in Washington. – Now we know it’s there. This discovery undermines our understanding of the lunar surface and raises intriguing questions about resources relevant to space exploration, he added.
“Something produces water and something has to trap it there”
Water is a precious resource in space and a key component of life as we know it. It is not known whether the one discovered on the moon will be easy to exploit. As part of the Artemis program, NASA wants to learn all about the presence of water on the moon before sending more people to its surface in 2024 and establishing a permanent human presence there by the end of the decade.
“Before the SOFIA observations, we knew there was some type of hydration,” said Casey Honniball, lead author, a graduate of the University of Hawaii at Manoa, Honolulu. “But we didn’t know how many, if any, were water molecules, the kind we drink every day, or something more like a pipe cleaner,” she added. “Without a dense atmosphere, the water on the moon’s sunlit surface should simply disappear into space,” said Honniball, who is now a PhD research associate at Goddard Space Flight Center in Greenbelt, Maryland. – But we see something. Something makes water and something must trap it there, she added.
Several forces can be involved in providing or creating this water. A rain of micrometeorites carrying a small amount of water can deposit water on the lunar surface when it hits it. Another possibility is a two-step process where the solar wind supplies hydrogen from the sun to the lunar surface and causes a chemical reaction with the oxygen-containing minerals in the soil to form hydroxyl. In the meantime, radiation from the bombardment of micrometeorites may change.
SOFIA results build on years of previous research into the presence of water on the moon. When the Apollo astronauts first returned from the moon in 1969, it was believed to be completely dry. Orbital and impact missions over the past 20 years, such as NASA’s Lunar Crater Observation and Detection, have confirmed the presence of ice in the constantly shaded craters around the Moon’s poles.
Meanwhile, several spacecraft – including the Cassini and Deep Impact missions, as well as the Indian Space Research Organization’s Chandrayaan-1 mission – and NASA’s ground-based Infrared Telescope, have surveyed the Moon’s surface and found evidence of hydration in sunny regions. However, these missions were unable to definitively distinguish between the form in which the hydrogen was present – water or hydroxyl.
More scientific discoveries are ahead of us
In the same issue of Nature Astronomy, scientists published a paper using theoretical models and data from NASA’s Lunar Reconnaissance Orbiter, indicating that water may be trapped in somewhat shaded areas where temperatures remain below freezing over more of the Moon than currently expected .
“Water is a valuable resource, both for scientific purposes and for use by our explorers,” said NASA scientist Jacob Bleacher. “If we are able to use the resources of the moon, we will be able to take less water and more equipment to enable new scientific discoveries,” he added.