For years, it was believed that the Moon was devoid of any significant surface water. And as a result, it seemed unlikely that our planet’s sole natural satellite would be capable of supporting life. Now, however, NASA scientists have found definite evidence of water, and the discovery could have major implications for the future of space travel.
It’s safe to say that the Moon has been an object of human fascination for many thousands of years. It was only with advances in science and technology in the 20th century, though, that we were actually able to get close to the astronomical body. And even now we’re still learning new things about the Moon all the time.
It was the Soviet Union that first set its sights on the Moon in the 1950s. In 1959 the country succeeded in coming close to the interplanetary body, too, through spacecraft Luna 1. Then the Soviets went a step further, when Luna 2 became the first man-made artifact to reach the Moon later that year. And before the decade’s end, Luna 3 took the first ever photos of the far side of the Moon.
From the 1960s, however, space exploration advanced at a dizzying speed. After the Soviet Union launched the first man – Yuri Gagarin – into orbit in 1961, President John F. Kennedy promised that the United States would land a man on the Moon before the ’70s rolled around. And JFK’s pledge paved the way for a series of unmanned missions to the Moon, which were undertaken in order to learn more about the strange lunar landscape. The Soviet Union also chose to conduct similar projects.
During this period, then, scientists gathered information about the Moon’s environment. And as a result, they discovered both that the lunar landscape featured many craters of different sizes and that it was covered by a fine dust. Researchers also learned that the Moon was made up of rocks not dissimilar to the ones on our own planet. Unlike Earth, though, the natural satellite had no atmosphere or magnetic field.
And human exploration of the Moon really got underway in late 1968. It was during that period, you see, that a manned Apollo 8 flight orbited the astrological body for nearly 24 hours – thus marking the first occasion in which the lunar landscape had been viewed by humans from close up. That being the case, it would be another seven months before man would successfully land on the Moon.
Yes, as we all know, Neil Armstrong and Buzz Aldrin – the crew members of Apollo 11 – famously touched down on the Moon’s Sea of Tranquility on July 20, 1969. The astronauts then explored the lunar landscape on foot for a couple of hours, picking up portions of rock as they went. And through these samples, scientists later concluded that the darker regions of the Moon had been formed by ancient volcanic lava that had solidified more than three billion years ago.
But although the rock fragments that Armstrong and Aldrin collected were found to be broadly akin to those on Earth, they were comparatively much drier in their composition. This discovery suggested in turn that the Moon housed no great reserves of water, nor did it seem likely that this had ever been the case.
That said, some scientists still held the opinion that there was indeed water present on the Moon. And in the 1990s that theory was lent further credence. It was then, you see, that the Clementine spacecraft found some proof that water in the form of ice could potentially exist in the south pole of the Moon. This point is constantly in shadow, meaning water there shouldn’t evaporate as a result of exposure to sunlight.
Nevertheless, it was suggested that water cannot exist on the surface of the Moon in liquid form; in the lunar environment, the molecules basically evaporate and escape into space. Therefore, from the 1960s onwards, many scientists have suggested that only ice water could be present at the Moon’s poles – if, indeed, there was any water at all.
But although scientists had theorized about the presence of ice pockets on the coolest areas of the Moon for decades, it wasn’t until 2018 that this hypothesis was confirmed. In that year, researchers finally found definite proof of water in the form of ice on the lunar surface. They also discovered that the deposits were sporadic in their locations, which suggested that the ice could have ancient origins.
For the first time, then, scientists could also accurately map the location of the ice deposits. And as expected, they were indeed confined to the poles of the Moon. At the south end, frozen water was mainly found in lunar craters; in the north, by contrast, ice was distributed over a larger area.
As a consequence, the lunar ice deposits were in the most remote parts of the Moon. Here, conditions are very harsh, with temperatures typically rising no higher than -250 °F. In addition, the regions that contain ice are never touched by natural light owing to the Moon’s axis being slightly tilted.
Heading the research group behind this important discovery was Shuai Li from Brown University and the University of Hawaii. He worked alongside Richard Elphic, who is based in Silicon Valley, California, at NASA’s Ames Research Center. And together with their colleagues, the duo used special NASA technology – known as the Moon Mineralogy Mapper – to demonstrate that ice could indeed be found on the lunar surface.
Explaining his team’s breakthrough in a statement obtained by CNN in August 2018, Li said, “We found that the distribution of ice on the lunar surface is very patchy, which is very different from other planetary bodies such as Mercury and Ceres where the ice is relatively pure and abundant… The spectral features of our detected ice suggest that they were formed by slow condensation from a vapor phase – either due to impact or water migration from space.”
The Moon Mineralogy Mapper – often referred to by its shortened name, M3 – left Earth for space in 2008. It was carried by an Indian spacecraft called Chandrayaan-1 and designed with the sole purpose of finding ice on the Moon. In effect, M3 both detects the reflective qualities of ice and gauges how it reacts to infrared light.
Thanks to the processes that M3 carries out, then, the mapper can tell the difference between vapor, liquid water and ice. And in a statement on its website, NASA pointed out that while other research had uncovered potential evidence of surface ice near the Moon’s south pole, the data from M3 offered definitive proof.
Understandably, the discovery of ice deposits on the Moon was an exciting one not only for scientists, but also for the entire space exploration community. You see, if water was indeed readily available on the lunar landscape, astronauts could perhaps use these reserves on any subsequent expeditions.
In fact, NASA officials had been eyeing up the Moon’s water as a potential resource for future missions as long ago as 2009. In an interview with the BBC, Mike Wargo, NASA’s chief lunar scientist for exploration systems, explained, “It can be used for drinking water. You can break it down and have breathable air for crews. But also, if you have significant quantities of this stuff, you have the constituents of one of the most potent rocket fuels: oxygen and hydrogen.”
And uncovering more information about the lunar ice deposits is something that NASA is focusing on at present. In the future, the space agency hopes to understand more about how the water got there and how it relates to the rest of the Moon’s surface.
Consequently, NASA is involved with a number of research projects concerning the Moon. And happily for the agency, those studies bore fruit in March 2019, when scientists studying the lunar landscape had yet another breakthrough. This time, they had discovered that water is actually in motion across the area of the Moon that is lit by the Sun.
The data that the scientists had used in their research had come from the Lunar Reconnaissance Orbiter, or LRO. This robotic spacecraft is being used by NASA to map the surface of the Moon. LRO is presently in orbit, moreover, as a means to locate potential resources, document radiation and seek out potential landing areas on the surface.
And thanks to the LRO, scientists were able to embark on the Lyman Alpha Mapping Project – or LAMP for short. This project measured particles on the lunar service in order to gain an idea of how the Moon’s water behaves and travels throughout the day, and the data that emerged as a consequence would prove fascinating.
As we’ve heard, experts once believed that the Moon was mainly dry. And if there was any water to be found on the lunar surface, it was assumed that it existed only in the areas near the north and south poles that never saw sunlight – as had been suggested by Li and his team. But it turned out that this wasn’t the whole truth.
Yes, through the data gathered by LAMP, scientists discovered that small amounts of water moved around on the surface of the Moon. And early on in the lunar day, the molecules were found to be intertwined with the Moon’s soil – so, before the face of the Moon heated up. However, come noon – when surface temperatures were at their highest – the water started to travel.
It seems that, after midday, water molecules are released from the lunar soil and bounce across the surface of the Moon. Following this, they usually come to rest in an area that is sufficiently cool enough for them to stay put. Alternatively, the molecules may populate the Moon’s barely existent atmosphere for a while; when temperatures drop again, though, they return to the lunar soil.
And such findings may have been music to the ears of Dr. Michael Poston, who works at the Southwest Research Institute in San Antonio, Texas. After all, he has spent much of his career researching the Moon’s water reserves. Prior to working on LAMP, for example, Poston had conducted experiments on lunar samples – including water – that had been collected by the Apollo space missions.
Simply put, Poston and others working in the field may have been enthused because the data gave them an idea of how much energy was needed to release water molecules from the lunar landscape. In addition, the information helped researchers comprehend further how water remains on the surface of the Moon. And understanding these two processes would be vital if Earthly visitors to the heavenly body are ever to harness such a resource on future missions.
In the NASA statement, Poston revealed, “Lunar hydration is tricky to measure from orbit due to the complex way that light reflects off the lunar surface. Previous research reported quantities of hopping water molecules that were too large to explain with known physical processes. I’m excited about these latest results because the amount of water interpreted here is consistent with what lab measurements indicate is possible.”
And in the NASA statement, Dr. Kurt Retherford – Poston’s colleague at the Southwest Research Institute and lead investigator of the LAMP instrument – also expressed his excitement over the discovery. Retherford said, “This is an important new result about lunar water – a hot topic as our nation’s space program returns to a focus on lunar exploration.”
Retherford further revealed how the team of scientists had used technology to follow the Moon’s water in a even closer manner than ever before. “We recently converted the LAMP’s light collection mode to measure reflected signals on the lunar dayside with more precision, allowing us to track more accurately where the water is and how much is present,” he explained.
And insights into the ways in which the Moon’s surface water moves and changes weren’t the only discoveries that the LAMP team made. In addition, they were also able to learn more about the lunar water cycle. And this information in turn enabled the group to rule out one theory regarding how water molecules had come to settle on the Moon in the first place.
Previously, scientists had suggested that hydrogen ions from solar winds were behind the water found on the Moon. Each time the Moon passes behind the Earth, though, our planet shields it from these winds. And as a consequence, this should mean – according to the prevailing theory, at least – that the water supply is blocked on these occasions.
However, LAMP scientists found this not to be the case. Instead, they discovered that the Moon’s surface water didn’t diminish when the astronomical body passed behind the Earth. In all, then, this suggested that lunar water deposits increase gradually rather than being supplied by the solar wind.
In the NASA press release announcing the discovery, scientist Amanda Hendrix explained the significance of this study. “These results aid in understanding the lunar water cycle,” she said. “[They] will ultimately help us learn about accessibility of water that can be used by humans in future missions to the Moon.”
And according to Hendrix, the Moon’s water supply could be a boon for future astronauts. “Lunar water can potentially be used by humans to make fuel or to use for radiation shielding or thermal management,” she explained. “If these materials do not need to be launched from Earth, that makes these future missions more affordable.”
The news of the LAMP discoveries was also celebrated by John Keller, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Goddard is in charge of the LRO mission that carried the LAMP instrument into lunar orbit. “This result is an important step in advancing the water story on the Moon and is a result of years of accumulated data from the LRO mission,” Keller said.
So, although the Moon may be our closest neighbor in the universe, it seems that we still have a lot to learn about our natural satellite. Even with the discovery of water, in fact, many mysteries surrounding the Moon remain – including its origin. And that’s why NASA is continuing to fund research into the lunar landscape in the hopes of perhaps establishing a human presence there in the future.
At the very least, learning more about the lunar landscape may help us to discover more about the universe that we inhabit. As Li told CNN, “Given that the Moon is our nearest planetary neighbor, understanding the processes [that] led to water ice on the Moon provides clues to understand the origin of water on Earth and throughout the solar system.”
“A future Moon mission is needed to examine the whole lunar PSRs [permanently shaded regions] to map out all water ices and understand the processes [that] led to water on the Moon,” Li added. “This work provides a road map for future exploration of the Moon – particularly the potential of water ice as a resource.”