“We already have, or at least understand, the technology needed for a moon base,” says Lewis Dartnell, an astrobiologist from the University of Westminster in London. “The time frame could be in a matter of years,” he adds, “if money were no object and nations around the world were to decide that they needed to build a lunar base together.”
Prof. Dartnell is not alone in his optimism. Many scientists, space engineers and industrialists believe that humanity is on the brink of a breakthrough in settlement. Recent developments could advance the realization of this vision.
For example, a report published last month stated that the radar used by the Chinese spacecraft that was the first to reach the far side of the moon is particularly useful for locating subterranean ice layers. One day, that ice may make it possible for people to remain on the moon for lengthy periods.
In another case, reported earlier this month, astronauts on the international space station succeeded in growing nutritive lettuce. It’s no simple matter to grow plants in a gravity-free environment. When the plants are irrigated, the water does not trickle down; the drops hang in the air and attach themselves to the leaves instead of the roots. The lettuce grown in space did not have a soil base, but sprouted in porous ceramic clay that traps air and water around the roots.
Prior to that, last summer, 50 years after the first moon landing, NASA announced the establishment of the Artemis program, which European, Canadian and Japanese space agencies have since joined. Its plans include setting up a permanent base on the moon by 2028. And this month, the U.S. administration stated that the budget of NASA would be increased by 12 percent next year and that billions would be earmarked for moon landings and settlement projects.
But the moon is not the only target intended for colonization. Technology entrepreneur Elon Musk maintains that a human city can be established on Mars by 2050. At the same time, Blue Origin, a company owned by Amazon CEO Jeff Bezos, is trying to develop huge spaceships that would serve as ecosystems, floating close to Earth, which would become colonies for trillions of people.
Of course, it’s not as simple as that: There are many obstacles to overcome.
“All the things we take for granted on Earth, like fresh air to breathe and water to drink, food to eat – these are things you have to do for yourself artificially while living beyond Earth and on the moon,” Dartnell notes. “We’d also have to become space farmers, growing food on the moon, because it will be way too expensive to keep launching it from Earth, which we currently do with the international space station.”
As to the feasibility of this, he points out that scientists have for a long time been “working on systems that generate breathable oxygen or recycle water, and we’re already doing this sort of thing on the international space station.”
But Dartnell admits there are other difficulties with lunar habitation as well.
“We’re protected from cosmic radiation on Earth, because we have a big magnetic field around our planet and a thick atmosphere above our heads, which absorbs all this radiation, these energetic particles from outer space. But that is not the case on the moon,” he explains.
“If you’re walking around the surface of the moon in a space suit, your body is being hit by these fast-moving radiation particles. So, if you’re living there long-term, for months or years at a time, you’d want to protect your body from this radiation, which can give you cancer and other problems later in life.”
Radiation is “probably the worst” hazard facing mankind on the moon, but far from the only one, says Prof. Jay Melosh, a geophysicist from Purdue University in Indiana.
“There are also huge temperature fluctuations – going from minus-170 Celsius (at night) to plus-100 Celsius over the course of a lunar day; meteorite impacts and so on. The lunar surface is also a terrible place for moving parts. Lunar dust is absolutely awful, it gets into and coats everything, sticking to it,” Melosh says.
“What limited the excursions of Apollo 17 [which included three days on the moon] was not time, but the dust, which caused their suits to leak like crazy, so they didn’t have enough oxygen. The dust is a real problem that isn’t discussed as much as it should be.”
Given the array of dangers, he notes, “the pictures you see of habitats on the moon and Mars with lovely little domes, lots of windows and stuff like that – those are all science fiction and they would not be habitable, because they don’t screen radiation. So those pictures they show would be death traps.”
The challenges of lunar habitation actually begin at the construction stage. To begin with, it will be very problematic to send heavy construction equipment to the moon. Second, as Haym Benaroya, a professor of mechanical and aerospace engineering at Rutgers University in New Jersey explains, on Earth such equipment harnesses the force of gravity to work for it, but “that won’t happen on the moon, with its much lower gravity. Things [i.e., earthmovers, cranes, etc.] will push themselves up, instead of digging.”
Furthermore, as Melosh points out, “On Earth, the basic problem engineers face is how to hold up the weight of a building, which is why we use supporting arches, for example, which transfer the weight to columns that in turn transfer it to the ground. However, on the moon or Mars, the problem is the opposite. You’re dealing with pressurized structures, and instead of worrying about them falling down, you need to prevent them from exploding.
“On the one hand, you have the pressure of the atmosphere we’ll have to artificially generate, and on the other side, you have a vacuum. It’s like having a tornado going over your house: The low pressure in the middle of it basically sucks the roof up into the vacuum of the tornado. On the moon, it’s even lower pressure than the strongest tornado possible, so we’ll need to find other solutions. Structures like those on Earth won’t survive in lunar conditions.”
'We already have, or at least understand, the technology needed for a moon base. The time frame could be in a matter of years.'
Although tests are being conducted of alternative construction materials, composed of such things as bacteria and mushrooms, Melosh and Benaroya are not convinced that these are practical options. Last January, scientists from India’s Space Research Organization announced that they had created “space bricks” from lunar soil.
“Creating bricks is one approach, but there are various others,” Benaroya says. “The most advanced concept today, I think, is to build in layers, with robots working the lunar surface and 3D printers using the material to print structures layer upon layer, like adding sheets of paper one on top of another.”
Melosh remains skeptical: “The materials used in 3D printing are very weak in tension and would not be suitable for the conditions on the moon. So that solution cannot stand on its own.”
As to how long it will be before any of this happens, Benaroya sums up: “If we’re talking about people going there temporarily, just a few months at a time, then I’d probably say something between 10-20 years. But if we want people there permanently, living their whole lives there, then something like 30-40 years could be realistic.”
Melosh, too, doubts that Elon Musk, or anyone else, will be colonizing Mars by 2050. Still, he believes that, with the investment of the necessary resources, “it might be only a few decades before we have a permanent outpost” on the moon.
In 2015, the European Space Agency presented to the world its plan for the “multi-partner moon project,” aka, the Moon Village. The initiative is part of a plan by ESA director general Jan Woerner “to go forward to the moon” within five years: specifically, to aim for some form of scientific reconnaissance vessel to land there by then. To that end, in 2018 the agency hired the international architectural firm Skidmore, Owings & Merrill, which designed the world’s tallest tower, the Burj Khalifa, in Dubai.
The plan is to locate the village on the rim of Shackleton Crater, near the south pole of the moon. It would thus have a view to Earth on the horizon, and its residents would enjoy the sunlight that is present in that region for almost the whole lunar year. Those conditions would also enable the large-scale production of solar energy. Additionally, it would be possible to make use of the deposits of ancient ice that lie deep within the crater, which could be used to produce two invaluable resources: water and – from that – oxygen.
Moon Village is envisioned as consisting of cylindrical habitation modules. Part of each module inflates, the other part has a rigid framework. A module consists of four stories, each possessing spaces that fill different functions.
The ground floor is devoted to command and control, means of connection to other modules and essential equipment for external activity. The second floor has workstations, laboratories, a medical room and a kitchen. The third floor is earmarked for the crew’s living quarters, and the top level would house a hydroponic farm and labs for growing food by alternative means.
The role of the first module that lands on the moon is to provide for all the needs of the four crew members for up to 500 days. Its four stories will have a total living space of 390 cubic meters. Connecting modules introduced as part of Moon Village will offer increasingly large spaces. In contrast to other models, this concept, known as One Moon, is only in the planning stage, and no usable prototype is envisaged at this time.
NASA’s Artemis program foresees a moon landing by 2024 and by 2028 the construction there of a functioning colony, which would become a transit station for launchings into deep space, notably Mars. The proposed landing site for the permanent base would be created at the moon’s south pole, where there is ice from which water can be produced, and the light and temperature conditions are better than those in the northern lunar regions.
To realize this goal, NASA is working on the Lunar Gateway, a smaller version of the international space station, which, in the first stage in the project, would orbit the moon and serve as a transit station en route to it. The next phase would be to land on the lunar surface, in 2024, in advance of constructing a permanent base there in 2028. This year, NASA is supposed to choose from among five models for lunar habitation that were submitted.
One possibility is using a group of interconnected, pressurized capsules similar to the one used as part of the international space station. These capsules would be brought to the moon and be buried three meters under its surface, which would enable them to offer protection against radiation, micro-meteorites and the vacuum effect. Another proposal under consideration is to launch folding structures that would be inflated to a volume of hundreds of cubic meters and thus be suitable for habitation.
One of the expandable, subterranean modules that NASA is examining is the B330 of Bigelow Aerospace, which contains two toilets, a shower, a bedroom with sleeping bags attached to the walls and areas for cooking, growing plants and for 3D printing. A small model was attached to the international space station in 2016 for experimental purposes. Bigelow says that if the space agency orders their product, they will be able to manufacture it within 42 days. The main problem is that these models are capable of supplying a habitable environment for only a small number of people and for a relatively limited time.
In light of the dangers lurking for us on the moon, it’s very possible that human life on Earth’s satellite will take place mainly underground. One possibility is a habitat established in lava tubes – vast tunnels below the lunar surface.
“These tubes were formed billions of years ago, when geological activity was still occurring on the moon,” Prof. Dartnell says. “The regolith – the ground on the moon itself – would absorb the radiation, so we’ll remain protected. You can still go onto the surface in a space suit, to walk around or to do your job.”
Similar underground caverns, naturally formed due to volcanic activity, exist on Earth, too, in Hawaii, New Mexico, California and Japan – but “there’s nothing close to the size we found on the moon,” Jay Melosh notes.
'The pictures you see of habitats on the moon and Mars with lovely little domes, lots of windows and stuff like that – those are all science fiction and they would not be habitable, because they don’t screen radiation.'
About six years ago, Melosh was part of the scientific team in a NASA mission in which a pair of satellites were launched into orbit around the moon and carried out measurements in search of “deficits of gravity,” which attest to the hollow cavernous spaces below the surface.
“We’re trying to find lava tubes on the moon whose roofs have not collapsed and which are strong enough to support human habitats,” he explains. “We were able to detect some tubes that were surprisingly big, kilometers in diameter – the longest one is 80 kilometers long and three or four kilometers high. We could provide a safe habitat for millions of people in the lunar lava tubes. In fact, we could fit the city of Los Angeles into that big one, with room to spare.”
According to this plan, access to the underground human cities would be via elevators with air locks on both sides. The elevators would primarily be used for transporting workers who are coming and going from their subterranean jobs.
These workers, Dartnell says, would be needed for quarrying resources such as titanium, metals from the platinum group and the helium-3 isotope, which is rare on Earth but plentiful on the moon. Fuel produced from the helium-3 would drive not only the engines of the spaceships but also the nuclear reactors that would supply energy to the underground communities.
Mining of the ice reserves would provide water. Afterward, by means of electrolysis, the water would be broken down into its two basic elements – hydrogen and oxygen – which would be released into the underground areas. Artificial light would also be conveyed via pipes, in different types and strengths to correspond with the 24-hour day on Earth, and in a way that would even mimic sunrise and sunset.
Because most of the light will be conveyed to the central part of the tube, the planners will need to ensure that the tall buildings are situated along the edges of the city to avoid blocking the light. Without soil for growing crops, and given the fact that sending animals to the moon is not currently on the agenda, the lunar denizens will probably have to rely primarily on hydroponic crops and meat alternatives created in labs or insects.
“The cities that will be built won’t be circular, like a city on Earth would be, but much longer, spreading down [and along the length of] the tunnel,” Dartnell observes.
Life in these subterranean reaches won’t be easy, Benaroya says. “Both the nuclear reactors that provide us with power and the landing sites of the spacecrafts will have to be far away from any settlement we’ll build, so a whole secondary infrastructure will also be necessary for them. I think more missions are required in order to gather data to help us decide where to locate our structures.”
Musk’s Mars dream
Elon Musk’s company SpaceX aspires to establishment of a permanent settlement on Mars by 2050. Its spacecraft, called Starships, each of which will accommodate 100 people, are planned to serve as temporary bases until the first cities are constructed.
In 2022, SpaceX plans to launch a pair of unmanned spacecraft to Mars, carrying supplies and technology to search for water sources and to establish initial infrastructure. In 2024, according to Musk’s ambitious plans (which will, like others described here, probably change due to the coronavirus epidemic), when Earth and Mars will be close again, four more spacecraft will be launched, this time carrying people as well as supplies. The six vessels will serve as initial residences for the space pioneers and the 600 tons of supplies they’ll need to mine ice, from which engine fuel will be produced, and to build residential structures, laboratories and greenhouses.
“Mars, because it’s a bigger planet and has more on its surface, will offer certain opportunities that wouldn’t be as easily available on the moon,” Dartnell notes. “For example, we think that in the northern hemisphere of Mars there is quite a lot of ice just underground, so you could effectively mine the ice and then melt it and purify it for drinking water, and you could split the water by using electricity, which will give you oxygen to breathe. You can take the air on Mars, which is pretty much pure carbon dioxide, and chemically convert it into rocket fuel, to power your spaceships.”
Still, he warns, “because Mars is farther away, it will be harder and more expensive to operate there. In addition, the moon orbits Earth, whereas both Mars and Earth orbit the sun. So, you can launch a rocket from the Earth to the moon whenever you’d like, and it would get there in two or three days.
“If you have some kind of an emergency on your lunar base, you can launch a rescue mission or return to Earth whenever you like. But with Mars, you have to wait for it to line up with Earth’s orbit. You have a specific window of time in which you can get from one to the other, about once every two years. So, if you have an emergency or a disaster on your Mars base, it’s very hard to come back quickly to Earth or launch a rescue mission.”
Because of the vast distance, Dartnell continues, the greatest problem in settling Mars may be the effects of a prolonged voyage in space on the human body: “When you’re in microgravity and you’re flinging around in free-fall, which looks like a lot of fun – and I’m sure it is – your body changes, because it’s not exposed to the pull of gravity. The skeleton and the muscles become weaker, even your heart grows weaker.
“When astronauts come back from the space station, they literally have to be helped out of their seat; they can’t walk for a couple of weeks, until their bodies re-adapt to our gravity. So, if it takes you six-seven months to get to Mars, you might not even be able to stand up once you get there, under Martian gravity. We need to solve this problem somehow, whether through pharmaceutical solutions or by creating artificial gravity.”
Bezos’ floating cities
In 2016, Jeff Bezos’ company, Blue Origin, first began working on Blue Moon, a robotic lander that is due to be used by NASA’s astronauts in their expected 2024 lunar landing. He announced his project to the public in 2017 and in May of last year unveiled a mock-up version of the lander. His vision for the future of human settlement in space features huge, artificial ecological systems in the form of vast spaceships that would orbit Earth.
His remarks recalled an occasion almost half a century earlier, when the American physicist Gerald O’Neill presented to Congress the Stanford torus: a model for human habitation in space that had been conceived for NASA by scientists at Stanford University. O’Neill maintained that it was unreasonable to envision humanity’s future on planets or other astronomical bodies, because they don’t have gravity like that on Earth, are small and too distant, and there is no way to support real-time communication between them and Earth.
The torus (the word refers to a rotating donut-like object), which could hold 10,000 to 140,000 people, was planned to turn on its axis once a minute in order to create artificial gravity through centrifugal force.
Given the host of dangers humanity faces on planets and the like, it may indeed be preferable to try to settle in space itself. In his presentation, Bezos referred explicitly to O’Neill’s concept and argued that although it may not happen in our lifetime, the young people among us may see the establishment of such colonies.
Bezos envisions his future ship as being able to accommodate a million people, making the international space station look like a pinprick by comparison. These immense colonies would be intended to house a trillion human beings who will float in space at a distance of a short, easy trip from Earth. Of course, besides artificial gravity, the ships would have to supply all their occupants’ needs, from air to breathe and water to drink, to a temperature fit for living. According to Bezos, the weather in them will be like “Maui on its best day, all year long.”
But despite the advantages in the establishment of human colonies that would float in space near Earth, we are closer, technologically speaking, to establishing structures on various astronomical bodies than to building vast spaceships capable of sustaining life on that scale.