For decades, scientists have held that the Earth-Moon system formed as a result of a collision between Earth and a Mars-sized object roughly 4.5 billion years ago. Known as the Giant Impact Hypothesis, this theory explains why Earth and the Moon are similar in structure and composition. Interestingly enough, scientists have also determined that during its early history, the Moon had a magnetosphere – much like Earth does today.
However, a new study led by researchers at MIT (with support provided by NASA) indicates that at one time, the Moon’s magnetic field may have actually been stronger than Earth’s. They were also able to place tighter constraints on when this field petered out, claiming it would have happened about 1 billion years ago. These findings have helped resolve the mystery of what mechanism powered the Moon’s magnetic field over time.
In the coming years, NASA is going back to the Moon for the first time since the Apollo Era. Rather than being a “footprints and flags” operation, Project Artemis is intended to be the first step in creating a sustainable human presence on the Moon. Naturally, this presents a number of challenges, not the least of which has to do with lunar regolith (aka. moondust). For this reason, NASA is investigating strategies for mitigating this threat.
It’s been over forty years since the Apollo Program wrapped up and the last crewed mission to the Moon took place. But in the coming years and decades, multiple space agencies plan to conduct crewed missions to the lunar surface. These includes NASA’s desire to return to the Moon, the ESA’s proposal to create an international Moon village, and the Chinese and Russian plans to send their first astronauts to the Moon.
For this reason, a great deal of research has been dedicated to what the health effects of long-duration missions to the Moon may be – particularly the effects a lower gravity environment would have on the human body. But in a recent study, a team of pharmacologists, geneticists and geoscientists consider how being exposed to lunar dust could have a serious effect on future astronauts’ lungs.
Because it has no atmosphere, the Moon’s surface has been pounded by meteors and micrometeroes for billions of years, which have created a fine layer of surface dust known as regolith. In addition, the Moon’s surface is constantly being bombarded by charged particles from the Sun, which cause the lunar soil to become electrostatically charged and stick to clothing.
Indications that lunar dust could cause health problems first emerged during the Apollo missions. After visiting the Moon, astronauts brought lunar soil back with them into the command module as it clung to their spacesuits. After inhaling the dust, Apollo 17 astronaut Harrison Schmitt described having symptoms akin to hay fever, which including sneezing, watery eyes and a sore throat.
While the symptoms were short-lived, researchers wanted to know what the long-term effects of lunar dust could be. There have also been indications that exposure to lunar dust could be harmful based on research that has shown how breathing dust from volcanic eruptions, dust storms and coal mines can cause bronchitis, wheezing, eye irritation and scarring of lung tissue.
Previous research has also shown that dust can cause damage to cells’ DNA, which can cause mutations and eventually lead to cancer. For these reasons, Caston and her colleagues were well-motivated to see what harmful effects lunar soil could have on the human body. For the sake of their study, the team exposed human lung cells and mouse brain cells to samples of simulated lunar soil.
These simulants were created by using dust samples from Earth that resemble soil found on the Moon’s lunar highlands and volcanic plains, which were then ground to a fine powder. What they found was that up to 90% of human lung cells and mouse neurons died when exposed to the dust samples. The simulants also caused significant DNA damage to mouse neurons, and the human lung cells were so effectively damaged that it was impossible to measure any damage to the cells’ DNA.
The results show that breathing lunar dust (even in minute quantities) could pose a serious health hazard to astronauts traveling to any airless bodies in the future. This includes not only the Moon, but also Mars and other terrestrial bodies like Mercury. Until now, this health hazard has been largely overlooked by space agencies seeking to understand the long-term health risks of space travel.
“There are risks to extraterrestrial exploration, both lunar and beyond, more than just the immediate risks of space itself,” said Rachel Caston. According to Bruce Demple, a biochemist at Stony Brook University School of Medicine and senior author of the new study, their results (coupled with the experience of the Apollo astronauts) indicate that prolonged exposure to lunar dust could impair airway and lung function.
What’s worse, he also indicated that if the dust induces inflammation in the lungs, it could increase the risk of more serious diseases like cancer. “If there are trips back to the Moon that involve stays of weeks, months or even longer, it probably won’t be possible to eliminate that risk completely,” he said.
Ergo, any attempts to mitigate the risks of mounting crewed missions to the Moon, Mars, and beyond will have to take into account exposure to not only low-gravity and radiation, but also electrostatically charged soil. Aside from limiting the duration of missions and the number of EVAs, certain protective counter-measures may need to be incorporated into any plans for long-duration missions.
One possibility is to have astronauts cycle through an airlock that would also spray their suits with water or a compound designed to neutralize the charge, thus washing them clean of dust before they enter the main habitat. Otherwise, astronauts working in the International Lunar Village (or any other off-world habitat for that matter) may have to wear breathing masks the entire time they are not in a spacesuit.
In the coming decades, NASA has some rather bold plans for space exploration. By the 2030s, they hope to mount their “Journey to Mars“. a crewed mission that will see astronauts traveling beyond Earth for the first time since the Apollo era. At the same time, private companies and organizations like SpaceX and MarsOne are hoping to start colonizing Mars within a decade or so.
According to Chris Hadfield, these mission concepts are all fine and good. But as he explained in a recent interview, our efforts should be focused on renewed exploration of the Moon and the creation of a lunar settlement before we do the same for Mars. In this respect, he is joined by organizations like the European Space Agency (ESA), Roscosmos, the Chinese National Space Agency (CNSA), and others.
When it comes to establishing a base on the Moon, the benefits are rather significant. For starters, a lunar outpost could serve as a permanent research base for teams of astronauts. In the same respect, it would present opportunities for scientific collaboration between space agencies and private companies – much in the same way the International Space Station does today.
On top of that, a lunar outpost could serve as a refueling station, facilitating missions deeper into the Solar System. According to estimates prepared by NexGen Space LLC (a consultant company for NASA), such a base could cut the cost of any future Mars missions by about $10 billion a year. Last, but not least, it would leverage key technologies that have been developed in recent years, from reusable rockets to additive manufacturing (aka. 3D printing).
And as Chris Hadfield stated in an interview with New Scientist, there are also a number of practical reasons for back to the Moon before going to Mars – ranging from distance to the development of “space expertise”. For those interested in science and space exploration, Chris Hadfield has become a household name in recent years. Before becoming an astronaut, he was a pilot with the Royal Canadian Air Force (RCAF) and flew missions for NORAD.
After joining the Canadian Space Agency (CSA) in 1992, he participated in two space missions – STS-74 and STS-100 in 1995 and 2001, respectively – as a Mission Specialist. These missions involved rendezvousing with the Russian space station Mir and the ISS. However, his greatest accomplishment occurred in 2012, when he became the first Canadian astronaut to command an ISS mission – Expedition 35.
During the course of this 148-day mission, Hadfield attracted significant media exposure due to his extensive use of social media to promote space exploration. In fact, Forbes described Hadfield as “perhaps the most social media savvy astronaut ever to leave Earth”. His promotional activities included a collaboration with Ed Robertson of The Barenaked Ladies and the Wexford Gleeks, singing “Is Somebody Singing?“(I.S.S.) via Skype.
The broadcast of this event was a major media sensation, as was his rendition of David Bowie’s “Space Oddity“, which he sung shortly before departing the station in May 2013. Since retiring from the Canadian Space Agency, Hadfield has become a science communicator and advocate for space exploration. And when it comes to the future, he was quite direct in his appraisal that the we need to look to the Moon first.
According to Hadfield, one of the greatest reasons for establishing a base on the Moon has to do with its proximity and the fact that humans have made this trip before. As he stated:
“With long-haul space exploration there is a whole smorgasbord of unknowns. We know some of the threats: the unreliability of the equipment, how to provide enough food for that length of time. But there are countless others: What are the impacts of cosmic rays on the human body? What sort of spacecraft do you need to build? What are the psychological effects of having nothing in the window for months and months? And going to a place that no one has ever been before, that can’t be discounted.”
In that, he certainly has a point. At their closest – i.e. when it is at “opposition with the Sun”, which occurs approximately every two years – Mars and Earth are still very far from each othre. In fact, the latest closest-approach occurred in 2003, when the two planets were roughly 56 million km (33.9 million miles) apart. This past July, the planets were again at opposition, where they were about 57.6 million km (35.8 million miles) apart.
During this time, astronauts would not only be subjected to a great deal of cosmic radiation, they would have to contend with the affects of microgravity. As studies that have been conducted aboard the ISS that have shown, long-term exposure to a microgravity environment can lead to losses in bone density, muscular atrophy, diminished eyesight, and organ damage.
Recent studies have also shown that exposure to radiation while on the surface of Mars would be quite significant. During its journey to Mars, the Curiosity rover recorded that it was subjected to average dose of 1.8 millisieverts (mSv) per day from inside its spaceship – the Mars Science Laboratory. During its first three hundred days on the surface, it was exposed to about 0.67 millisieverts (mSv) per day.
This is about half and one-fifth (respectively) of what people are exposed to during an average here on Earth. While this falls outside of NASA’s official guidelines, it is still within the guidelines of other space agencies. But to make matter worse, a new study from the University of Nevada, Las Vegas, concluded that exposure to cosmic rays could cause cell damage that would spread to other cells in the body, effectively doubling the risk of cancer.
The risks of going to the Moon, in contrast, are easy to predict. Thanks to the Apollo missions, we know that it takes between two and three days to travel from the Earth to the Moon. The Apollo 11 mission, for example, launched from the Cape Kennedy on July 16th, 1969, and arrived in lunar orbit by July 19th, 1969 – spending a total of 51 hours and 49 minutes in space. Astronauts conducting this type of mission would therefore be subject to far less radiation.
Granted, the surface of the Moon is still exposed to significant amounts of radiation since the Moon has no atmosphere to speak of. But NASA estimates that walls which are 2.5 meters in thickness (and made from lunar regolith) will provide all the necessary shielding to keep astronauts or colonists safe. Another good reason to go to the Moon first, according to Hadfield, is because expertise in off-world living is lacking.
“There are six people living on the International Space Station, and we have had people there continuously for nearly 17 years,” he said. “But the reality is we have not yet figured out how to live permanently off-planet. So I think if we follow the historically driven pattern then the moon would be first. Not just to reaffirm that we can get there, but to show that we can also live there.”
But perhaps the best reason to settle the Moon before moving onto Mars has to do with the fact that exploration has always been about taking the next step, and then the next. One cannot simply leap from one location to the next, and expect successful results. What are required is baby-steps. And in time, sufficient traction can be obtained and the process will build up speed, enabling steps that are greater and more far-reaching. Or as Hadfield put it:
“For tens of thousands of years humans have followed a pattern on Earth: imagination, to technology-enabled exploration, to settlement. It’s how the first humans got to Australia 50,000 or 60,000 years ago, and how we went from Yuri Gagarin and Alan Shepherd orbiting Earth to the first people putting footprints on the moon, to people living in orbit.
Based on this progression, one can therefore see why Hadfield and others beleive that the next logical step is to return to the Moon. And once we establish a foothold there, we can then use it to launch long-range missions to Mars, Venus, and beyond. Incremental steps that eventually add up to human beings setting foot on every planet, moon, and larger body in the Solar System.
On the subject of lunar colonization, be sure to check out our series on Building a Moon Base, by Universe Today’s own Ian O’Neill.
Long before the Apollo missions reached the Moon, Earth’s only satellites has been the focal point of intense interest and research. But thanks to the samples of lunar rock that were returned to Earth by the Apollo astronauts, scientists have been able to conduct numerous studies to learn more about the Moon’s formation and history. A key research goal has been determining how much volatile elements the Moon possesses.
Intrinsic to this is determining how much water the Moon possesses, and whether it has a “wet” interior. If the Moon does have abundant sources of water, it will make establishing outposts there someday much more feasible. However, according to a new study by an international team of researchers, the interior of the Moon is likely very dry, which they concluded after studying a series of “rusty” lunar rock samples collected by the Apollo 16 mission.
Determining how rich the Moon is in terms of volatile elements and compounds – such as zinc, potassium, chlorine, and water – is important because it provides insight into how the Moon and Earth formed and evolved. The most-widely accepted theory is that Moon is the result of “catastrophic formation”, where a Mars-sized object (named Theia) collided with Earth about 4.5 billion years ago.
The debris kicked up by this impact eventually coalesced to form the Moon, which then moved away from Earth to assume its current orbit. In accordance with this theory, the Moon’s surface would have been an ocean of magma during its early history. As a result, volatile elements and compounds within the Moon’s mantle would have been depleted, much in the same way that the Earth’s upper mantle is depleted of these elements.
“It’s been a big question whether the moon is wet or dry. It might seem like a trivial thing, but this is actually quite important. If the moon is dry – like we’ve thought for about the last 45 years, since the Apollo missions – it would be consistent with the formation of the Moon in some sort of cataclysmic impact event that formed it.”
For the sake of their study, the team examined a lunar rock named “Rusty Rock 66095” to determine the volatile content of the Moon’s interior. These rocks have mystified scientists since they were first brought back by the Apollo 16 mission in 1972. Water is an essential ingredient to rust, which led scientists to conclude that the Moon must have an indigenous source of water – something which seemed unlikely, given the Moon’s extremely tenuous atmosphere.
Using a new chemical analysis, Day and his colleagues determined the levels of istopically light zinc (Zn66) and heavy chlorine (Cl37), as well as the levels of heavy metals (uranium and lead) in the rock. Zinc was the key element here, since it is a volatile element that would have behaved somewhat like water under the extremely hot conditions that were present during the Moon’s formation.
Ultimately, the supply of volatiles and heavy metals in the sample support the theory that volatile enrichment of the lunar surface occurred as a result of vapor condensation. In other words, when the Moon’s surface was still an ocean of hot magma, its volatiles evaporated and escaped from the interior. Some of these then condensed and were deposited back on the surface as it cooled and solidified.
This would explain the volatile-rich nature of some rocks on the lunar surface, as well as the levels of light zinc in both the Rusty Rock samples and the previously-studied volcanic glass beads. Basically, both were enriched by water and other volatiles thanks to extreme outgassing from the Moon’s interior. However, these same conditions meant that most of the water in the Moon’s mantle would have evaporated and been lost to space.
This represents something of a paradox, in that it shows how rocks that contain water were formed in a very dry, interior part of the Moon. However, as Day indicated, it offers a sound explanation for an enduring lunar mystery:
“I think the Rusty Rock was seen for a long time as kind of this weird curiosity, but in reality, it’s telling us something very important about the interior of the moon. These rocks are the gifts that keep on giving because every time you use a new technique, these old rocks that were collected by Buzz Aldrin, Neil Armstrong, Charlie Duke, John Young, and the Apollo astronaut pioneers, you get these wonderful insights.”
These results contradict other studies that suggest the Moon’s interior is wet, one of which was recently conducted by researchers at Brown University. By combining data provided by Chandrayaan-1 and the Lunar Reconnaissance Orbiter (LRO) with new thermal profiles, the Brown research team concluded that lots of water exists within volcanic deposits on the Moon’s surface, which could also mean there are vast quantities of water in the Moon’s interior.
To these, Day emphasized that while these studies present evidence that water exists on the lunar surface, they have yet to offer a solid explanation for what mechanisms deposited it on the surface. Day and his colleague’s study also flies in the face of other recent studies, which claim that the Moon’s water came from an external source – either by comets which deposited it, or from Earth during the formation of the Earth-Moon system.
Those who believe that lunar water was deposited by comets cite the similarities between the ratios of hydrogen to deuterium (aka. “heavy hydrogen”) in both the Apollo lunar rock samples and known comets. Those who believe the Moon’s water came from Earth, on the other hand, point to the similarity between water isotopes on both the Moon and Earth.
In the end, future research is needed to confirm where all of the Moon’s water came from, and whether or not it exists within the Moon’s interior. Towards this end, one of Day’s PhD students – Carrie McIntosh – is conducting her own research into the lunar glass beads and the composition of the deposits. These and other research studies ought to settle the debate soon enough!
And not a moment too soon, considering that multiple space agencies hope to build a lunar outpost in the upcoming decades. If they hope to have a steady supply of water for creating hydrazene (rocket fuel) and growing plants, they’ll need to know if and where it can be found!
For decades, scientists have been of the belief that the Moon, Earth’s only natural satellite, was four and a half billion years old. According to this theory, the Moon was created from a fiery cataclysm produced by a collision between the Earth with a Mars-sized object (named Theia) roughly 100 million years after the formation of primordial Earth.
But according to a new study by researchers from UCLA (who re-examined some of the Apollo Moon Rocks), these estimates may have been off by about 40 to 140 million years. Far from simply adjusting our notions of the Moon’s proper age, these findings are also critical to our understanding of the Solar System and the formation and evolution of its rocky planets.
These fragments were of a compound known as zircon, a type of silicate mineral that contains trace amounts of radioactive elements (like uranium, thorium, and lutetium). As Kevin McKeegan, a UCLA professor of geochemistry and cosmochemistry and a co-author of the study, explained, “Zircons are nature’s best clocks. They are the best mineral in preserving geological history and revealing where they originated.”
By examining the radioactive decay of these elements, and correcting for cosmic ray exposure, the research team was able to get highly precise estimates of the zircon fragments ages. Using one of UCLA’s mass spectrometers, they were able to measure the rate at which the deposits of uranium in the zircon turned into lead, and the deposits of lutetium turned into hafnium.
In the end, their data indicated that the Moon formed about 4.51 billion years ago, which places its birth within the first 60 million years of the Solar System or so. Previously, dating Moon rocks proved difficult, mainly because most of them contained fragments of many different kinds of rocks, and these samples were determined to be tainted by the effects of multiple impacts.
However, Barboni and her team were able to examine eight zircons that were in good condition. More importantly, these silicate deposits are believed to have formed shortly after the collision between Earth and Theia, when the Moon was still an unsolidified mass covered in oceans of magma. As these oceans gradually cooled, the Moon’s body became differentiated between its crust, mantle and core.
Because zircon minerals were formed during the initial magma ocean, uranium-lead dating reaches all the way back to a time before the Moon became a solidified mass. As Edward Young, a UCLA professor of geochemistry and cosmochemistry and a co-author of the study, put it, “Mélanie was very clever in figuring out the Moon’s real age dates back to its pre-history before it solidified, not to its solidification.”
These findings have not only determined the age of the Moon with a high degree of accuracy (and for the first time), it also has implications for our understanding of when and how rocky planes formed within the Solar System. By placing accurate dates on when certain bodies formed, we are able to understand the context in which they formed, which also helps to determine what mechanisms were involved.
And this was just the first revelation produced by the research team, which hopes to continue studying the zircon fragments to see what they can learn about the Moon’s early history.
Ever since we began sending crewed missions to the Moon, people have been dreaming of the day when we might one day colonize it. Just imagine, a settlement on the lunar surface, where everyone constantly feels only about 15% as heavy as they do here on Earth. And in their spare time, the colonists get to do all kinds of cool research trek across the surface in lunar rovers. Gotta admit, it sounds fun!
More recently, the idea of prospecting and mining on the Moon has been proposed. This is due in part to renewed space exploration, but also the rise of private aerospace companies and the NewSpace industry. With missions to the Moon schedules for the coming years and decades, it seems logical to thinking about how we might set up mining and other industries there as well?
Several proposals have been made to establish mining operations on the Moon; initially by space agencies like NASA, but more recently by private interests. Many of the earliest proposals took place during the 1950s, in response to the Space Race, which saw a lunar colony as a logical outcome of lunar exploration.
For instance, in 1954 Arthur C. Clarke proposed a lunar base where inflatable modules were covered in lunar dust for insulation and communications were provided by a inflatable radio mast. And in 1959, John S. Rinehart – the director of the Mining Research Laboratory at the Colorado School of Mines – proposed a tubular base that would “float” across the surface.
Since that time, NASA, the US Army and Air Force, and other space agencies have issued proposals for the creation of a lunar settlement. In all cases, these plans contained allowances for resource utilization to make the base as self-sufficient as possible. However, these plans predated the Apollo program, and were largely abandoned after its conclusion. It has only been in the past few decades that detailed proposals have once again been made.
For instance, during the Bush Administration (2001-2009), NASA entrtained the possibility of creating a “lunar outpost”. Consistent with their Vision for Space Exploration (2004), the plan called for the construction of a base on the Moon between 2019 and 2024. One of the key aspects of this plan was the use of ISRU techniques to produce oxygen from the surrounding regolith.
These plans were cancelled by the Obama administration and replaced with a plan for a Mars Direct mission (known as NASA’s “Journey to Mars“). However, during a workshop in 2014, representatives from NASA met with Harvard geneticist George Church, Peter Diamandis from the X Prize Foundation and other experts to discuss low-cost options for returning to the Moon.
The workshop papers, which were published in a special issue of New Space, describe how a settlement could be built on the Moon by 2022 for just $10 billion USD. According to their papers, a low-cost base would be possible thanks to the development of the space launch business, the emergence of the NewSpace industry, 3D printing, autonomous robots, and other recently-developed technologies.
In 2010, NASA established the Robotic Mining Competition, an annual incentive-based competition where university students design and build robots to navigate a simulated Martian environment. One of the most-important aspects of the competition is creating robots that can rely on ISRU to turn local resources into usable materials. The applications produced are also likely to be of use during future lunar missions.
And the NewSpace industry has also been producing some interesting proposals of late. In 2010, a group of Silicon Valley entrepreneurs came together for create Moon Express, a private company that plans to offer commercial lunar robotic transportation and data services, as well as the a long-term goal of mining the Moon. In December of 2015, they became the first company competing for the Lunar X Prize to build and test a robotic lander – the MX-1.
In 2010, Arkyd Astronautics (renamed Planetary Resources in 2012) was launched for the purpose of developing and deploying technologies for asteroid mining. In 2013, Deep Space Industries was formed with the same purpose in mind. Though these companies are focused predominantly on asteroids, the appeal is much the same as lunar mining – which is expanding humanity’s resource base beyond Earth.
Based on the study of lunar rocks, which were brought back by the Apollo missions, scientists have learned that the lunar surface is rich in minerals. Their overall composition depends on whether the rocks came from lunar maria (large, dark, basaltic plains formed from lunar eruptions) or the lunar highlands.
Rocks obtained from lunar maria showed large traces of metals, with 14.9% alumina (Al²O³), 11.8% calcium oxide (lime), 14.1% iron oxide, 9.2% magnesia (MgO), 3.9% titanium dioxide (TiO²) and 0.6% sodium oxide (Na²O). Those obtained from the lunar highlands are similar in composition, with 24.0% alumina, 15.9% lime, 5.9% iron oxide, 7.5% magnesia, and 0.6% titanium dioxide and sodium oxide.
These same studies have shown that lunar rocks contain large amounts of oxygen, predominantly in the form of oxidized minerals. Experiments have been conducted that have shown how this oxygen could be extracted to provide astronauts with breathable air, and could be used to make water and even rocket fuel.
The Moon also has concentrations of Rare Earth Metals (REM), which are attractive for two reasons. On the one hand, REMs are becoming increasingly important to the global economy, since they are used widely in electronic devices. On the other hand, 90% of current reserves of REMs are controlled by China; so having a steady access to an outside source is viewed by some as a national security matter.
Similarly, the Moon has significant amounts of water contained within its lunar regolith and in the permanently shadowed areas in its north and southern polar regions.This water would also be valuable as a source of rocket fuel, not to mention drinking water for astronauts.
But since that time, multiple missions have not only found samples of water on the lunar surface, but revealed evidence of where it came from. The first was India’s Chandrayaan-1 mission, which sent an impactor to the lunar surface on Nov. 18th, 2008. During its 25-minute descent, the impact probe’s Chandra’s Altitudinal Composition Explorer (CHACE) found evidence of water in the Moon’s thin atmosphere.
In November 2009, the NASA LCROSS space probe made similar finds around the southern polar region, as an impactor it sent to the surface kicked up material shown to contain crystalline water. In 2012, surveys conducted by the Lunar Reconnaissance Orbiter (LRO) revealed that ice makes up to 22% of the material on the floor of the Shakleton crater (located in the southern polar region).
But perhaps the most valuable commodity on the surface of the Moon might be helium-3. Helium-3 is an atom emitted by the Sun in huge amounts, and is a byproduct of the fusion reactions that take place inside. Although there is little demand for helium-3 today, physicists think they’ll serve as the ideal fuel for fusion reactors.
The Sun’s solar wind carries the helium-3 away from the Sun and out into space – eventually out of the Solar System entirely. But the helium-3 particles can crash into objects that get in their way, like the Moon. Scientists haven’t been able to find any sources of helium-3 here on Earth, but it seems to be on the Moon in huge quantities.
From a commercial and scientific point of view, there are several reasons why Moon mining would be beneficial to humanity. For starters, it would be absolutely essential to any plans to build a settlement on the Moon, as in-situ resource utilization (ISRU) would be far more cost effective than transporting materials from Earth.
Also, it is predicted that the proposed space exploration efforts for the 21st century will require large amounts of materiel. That which is mined on the Moon would be launched into space at a fraction of the cost of what is mined here on Earth, due to the Moon’s much lower gravity and escape velocity.
In addition, the Moon has an abundance of raw materials that humanity relies on. Much like Earth, it is composed of silicate rocks and metals that are differentiated between a geochemically distinct layers. These consist of is iron-rich inner core, and iron-rich fluid outer core, a partially molten boundary layer, and a solid mantle and crust.
In addition, it has been recognized for some time that a lunar base – which would include resource operations – would be a boon for missions farther into the Solar System. For missions heading to Mars in the coming decades, the outer Solar System, or even Venus and Mercury, the ability to be resupplied from an lunar outpost would cut the cost of individual missions drastically.
Naturally, the prospect of setting up mining interests on the Moon also presents some serious challenges. For instance, any base on the Moon would need to be protected from surface temperatures, which range from very low to high – 100 K (-173.15 °C;-279.67 °F) to 390 K (116.85 °C; 242.33 °F) – at the equator and average 150 K (-123.15 °C;-189.67 °F) in the polar regions.
Radiation exposure is also an issue. Due to the extremely thin atmosphere and lack of a magnetic field, the lunar surface experiences half as much radiation as an object in interplanetary space. This means that astronauts and/or lunar workers would at a high risk of exposure to cosmic rays, protons from solar wind, and the radiation caused by solar flares.
Then there’s the Moon dust, which is an extremely abrasive glassy substance that has been formed by billions of years of micrometeorite impacts on the surface. Due to the absence of weathering and erosion, Moon dust is unrounded and can play havoc with machinery, and poses a health hazard. Worst of all, its sticks to everything it touches, and was a major nuisance for the Apollo crews!
And while the lower gravity is attractive as far as launches are concerned, it is unclear what the long-term health effects of it will be on humans. As repeated research has shown, exposure to zero-gravity over month-long periods causes muscular degeneration and loss of bone density, as well as diminished organ function and a depressed immune system.
And while there has been plenty of speculation about a “loophole” which does not expressly forbid private ownership, there is no legal consensus on this. As such, as lunar prospecting and mining become more of a possibility, a legal framework will have to be worked out that ensures everything is on the up and up.
Though it might be a long way off, it is not unreasonable to think that someday, we could be mining the Moon. And with its rich supplies of metals (which includes REMs) becoming part of our economy, we could be looking at a future characterized by post-scarcity!
Over the course of the past few decades, our ongoing exploration the Solar System has revealed some surprising discoveries. For example, while we have yet to find life beyond our planet, we have discovered that the elements necessary for life (i.e organic molecules, volatile elements, and water) are a lot more plentiful than previously thought. In the 1960’s, it was theorized that water ice could exist on the Moon; and by the next decade, sample return missions and probes were confirming this.
Since that time, a great deal more water has been discovered, which has led to a debate within the scientific community as to where it all came from. Was it the result of in-situ production, or was it delivered to the surface by water-bearing comets, asteroids and meteorites? According to a recent study produced by a team of scientists from the UK, US and France, the majority of the Moon’s water appears to have come from meteorites that delivered water to Earth and the Moon billions of years ago.
For the sake of their study, which appeared recently in Nature Communications, the international research team examined the samples of lunar rock and soil that were returned by the Apollo missions. When these samples were originally examined upon their return to Earth, it was assumed that the trace of amounts of water they contained were the result of contamination from Earth’s atmosphere since the containers in which the Moon rocks were brought home weren’t airtight. The Moon, it was widely believed, was bone dry.
However, that which was discovered on the surface paled in comparison the water that was discovered beneath it. Evidence of water in the interior was first revealed by the ISRO’s Chandrayaan-1 lunar orbiter – which carried the NASA’s Moon Mineralogy Mapper (M3) and delivered it to the surface. Analysis of this and other data has showed that water in the Moon’s interior is up to a million times more abundant than what’s on the surface.
The presence of so much water beneath the surface has begged the question, where did it all come from? Whereas water that exists on the Moon’s surface in lunar regolith appears to be the result of interaction with solar wind, this cannot account for the abundant sources deep underground. A previous study suggested that it came from Earth, as the leading theory for the Moon’s formation is that a large Mars-sized body impacted our nascent planet about 4.5 billion years ago, and the resulting debris formed the Moon. The similarity between water isotopes on both bodies seems to support that theory.
However, according to Dr. David A. Kring, a member of the research team that was led by Jessica Barnes from Open University, this explanation can only account for about a quarter of the water inside the moon. This, apparently, is due to the fact that most of the water would not have survived the processes involved in the formation of the Moon, and keep the same ratio of hydrogen isotopes.
Instead, Kring and his colleagues examined the possibility that water-bearing meteorites delivered water to both (hence the similar isotopes) after the Moon had formed. As Dr. Kring told Universe Today via email:
“The current study utilized analyses of lunar samples that had been collected by the Apollo astronauts, because those samples provide the best measure of the water inside the Moon. We compared those analyses with analyses of meteoritic samples from asteroids and spacecraft analyses of comets.”
By comparing the ratios of hydrogen to deuterium (aka. “heavy hydrogen”) from the Apollo samples and known comets, they determined that a combination of primitive meteorites (carbonaceous chondrite-type) were responsible for the majority of water to be found in the Moon’s interior today. In addition, they concluded that these types of comets played an important role when it comes to the origins of water in the inner Solar System.
For some time, scientists have argued that the abundance of water on Earth may be due in part to impacts from comets, trans-Neptunian objects or water-rich meteoroids. Here too, this was based on the fact that the ratio of the hydrogen isotopes (deuterium and protium) in asteroids like 67P/Churyumov-Gerasimenko revealed a similar percentage of impurities to carbon-rich chondrites that were found in the Earth’s coeans.
But how much of Earth’s water was delivered, how much was produced indigenously, and whether or not the Moon was formed with its water already there, have remained the subject of much scholarly debate. Thank to this latest study, we may now have a better idea of how and when meteorites delivered water to both bodies, thus giving us a better understanding of the origins of water in the inner Solar System.
“Some meteoritic samples of asteroids contain up to 20% water,” said Kring. “That reservoir of material – that is asteroids – are closer to the Earth-Moon system and, logically, have always been a good candidate source for the water in the Earth-Moon system. The current study shows that to be true. That water was apparently delivered 4.5 to 4.3 billion years ago.“
The existence of water on the Moon has always been a source of excitement, particularly to those who hope to see a lunar base established there someday. By knowing the source of that water, we can also come to know more about the history of the Solar System and how it came to be. It will also come in handy when it comes time to search for other sources of water, which will always be a factor when trying to establishing outposts and even colonies throughout the Solar System.
Returning to the Moon has been the fevered dream of many scientists and astronauts. Ever since the Apollo Program culminated with the first astronauts setting foot on the Moon on July 20th, 1969, we have been looking for ways to go back to the Moon… and to stay there. In that time, multiple proposals have been drafted and considered. But in every case, these plans failed, despite the brave words and bold pledges made.
However, in a workshop that took place in August of 2014, representatives from NASA met with Harvard geneticist George Church, Peter Diamandis from the X Prize Foundation and other parties invested in space exploration to discuss low-cost options for returning to the Moon. The papers, which were recently made available in a special issue of New Space, describe how a settlement could be built on the Moon by 2022, and for the comparatively low cost of $10 billion.
On July 14th, 2015, the New Horizons space probe made history when it became the first spacecraft to conduct a flyby of the dwarf planet of Pluto. Since that time, it has been making its way through the Kuiper Belt, on its way to joining Voyager 1 and 2 in interstellar space. With this milestone reached, many are wondering where we should send our spacecraft next.
Naturally, there are those who recommend we set our sights on our nearest star – particularly proponents of interstellar travel and exoplanet hunters. In addition to being Earth’s immediate neighbor, there is the possibility of one or more exoplanets in this system. Confirming the existence of exoplanets would be one of the main reasons to go. But more than that, it would be a major accomplishment!