When the first astronomers turned their eyes to the heavens tens of thousands of years ago, their view was unobscured by the glow of city lights. At night, a pristine black sheet stretched across an unreachable ceiling overhead. The centerpiece of this ancient nightscape was a flat gray disc that hung in the sky: the moon.

Robert Rodriguez

We used to worship the moon, tell each other stories to explain its mysteries. In Australia, the Indigenous Yolngu people named it "Ngalindi," believing a full moon represented an indolent, pot-bellied man with several wives. As the moon cycled through its phases, the Yolngu believed Ngalindi's wives had taken to his body with their axes, slicing pieces away, leaving only a crescent slither. Similar stories abound in Aztec culture and the myths of ancient Mesopotamia, East Asia, India and Greece.

But on July 20, 1969, we stepped onto a lunar sea and saw the moon's surface, up close, for the very first time. The ground was dead and cratered. Only dusty plains stretched out before us.

The moon was no longer a god to be worshiped. It was a destination. A place we could visit, an object we could touch.

Over the next three years, 12 humans walked on the surface of the moon, piloting rovers across Rima Hadley and Stone Mountain. They pilfered moon soil, studied rocks, visited impact craters and planted flags. On Dec. 14 1972, NASA astronauts in the Apollo 17 mission climbed back into their lunar spacecraft and departed the moon for Earth. It was the last time humans ever set foot on the moon.

But in 2019, the moon is being probed and explored once again. In January, China landed the first spacecraft on the far side of the moon. Israel's Beresheet lander became the first private spacecraft to reach the moon, crashing onto its surface in April. And NASA doubled down on efforts to put humans back on the moon before 2025 "by any means necessary." It's an ambitious goal, with the hope of establishing a permanent human presence on the moon and in lunar orbit at the end of the next decade.

The immediate future of the moon will see us build on those first steps taken in July 1969. We'll send more robotic landers and rovers to conduct experiments on our behalf. China already has another Chang'e mission planned for this year and India, too, will look to land on the surface before the end of the year. In our stead, the robots will search for water and explore the lunar highlands for the resources necessary to establish a more permanent presence.

Chang'e 4 made the first soft landing on the moon's far side in January 2019. China National Space Administration/Xinhua via Getty

Looking further ahead, we'll prepare to truly colonize the moon. We'll mine the sublunar layers and smelt its rock for metals and oxygen. We'll live at its poles, erecting inflatable shelters, communications centers and laboratories, and performing experiments not possible from the surface of the Earth. Eventually, we'll depart for further into the cosmos and find our way to Mars.

But it starts with the moon.

What follows is a decade-by-decade account of the future of our moon, featuring the thoughts and ideas of some of the world's leading scientists, astronomers, space archeologists, sci-fi authors and futurists. Predicting the future is nigh on impossible. Who would have thought in 1972 that we wouldn't return to the moon for at least 50 years? Certainly, we'll get it wrong. Already, there are doubts about NASA's coming moon missions, with delays and budgetary deficiencies stifling progress.

But advancing our exploration of the moon requires us to think beyond just returning. The prognosis for moon colonization may seem optimistic but it's grounded in reality: We have a direction, a schedule and the pioneering minds required to start our future on the moon. Importantly, we have a renewed will to go back.

Presented here is a grand view of the future, envisioning the moon as a scientific outpost, a deep space training facility, a tourist destination and, eventually, the first stop in humanity's ascent deeper into our solar system.

Our first mission is to go back.

After leaving the magnificent, desolate plains of the moon a half-century ago, NASA is gearing up to put humans back on the surface by 2024. That mission, known as Artemis 3, will mark a number of milestones in lunar exploration, including putting the first woman on the moon. Of the current crop of 12 female astronauts active with NASA, one will plant her boot in the lunar regolith during Artemis 3.

On Earth, the triumphant return will be watched live by more than 3 billion people on TV, across the web and on their phones. Unlike Apollo 11, broadcast to the world in grainy black-and-white, the new mission takes advantage of modern camera technology, giving viewers the most impressive look at the lunar surface yet.

"Next time we go to the moon will have full high-def, 3D images coming back, and we'll be able to receive those images with no problem at all," says Glen Nagle, outreach lead at the Canberra Deep Space Communication Complex.

It's not just humans returning to the moon, however, and NASA isn't the only space agency going there. China's Chang'e program has already been wildly successful and during the 2020s it continues to land multiple robots across the moon before extending the program to incorporate human lunar exploration. By the end of the decade, the first Chinese astronauts are preparing to make their way to the surface of the moon.

The Orion spacecraft is designed to carry humans into deep space. NASA

Getting to the moon is still an expensive and difficult process, but we've become a little better at it. The Lunar Orbital Platform-Gateway, an international space station in orbit around the moon, begins construction in 2022 and will be approaching completion by 2030. The eight-year project has its detractors, but with the backing of multiple space agencies, it aims to be a stepping stone for humans to escape low Earth orbit and get into space. It consists of a series of modules designed for habitation, experimentation and provides a "spaceport" of sorts, where spacecraft can be refueled and resupplied.

With the Gateway in orbit, our understanding of the moon and its resources dramatically increases as the surface and subsurface are surveyed, probed and analyzed. Returning humans to the moon is just the start of hundreds of scientific experiments focused on sustaining our presence there.

"I think we'll see the establishment of research capability. Initially, you'll see robotic missions, which will make initial measurements, do some science in new locations, [and] explore things like the ice that we know now is at the lunar poles," says James Carpenter from the European Space Agency's directorate of human and robotic exploration.

"And then over time, you'll see this building up research capability, essentially, with humans tending that research infrastructure, so you may visit something that looks a bit like Antarctica, with a sustained research capability at the lunar surface."

One of the most important short-term goals is improving our knowledge of the water ice located at the lunar poles. Direct evidence of this water ice was found within impact craters in 2018 and our initial intrepid steps on the moon will focus on how we can use this water, sustainably, to aid our exploration efforts. Carpenter explains there's a lot of work to do during this decade because we don't know a lot about the distribution or accessibility of the water, only that it will be a critical resource for extending our stay.

However, science isn't the only reason for heading to the moon.

"The moon is potentially quite an awesome tourist spot," says Andy Weir, author of sci-fi novel The Martian. Weir's second novel, Artemis, imagines a moon colony funded primarily by tourism, with citizens of Earth paying upward of $70,000 to visit the moon. "If there was a city on the moon, that's the only place you can go to look at Earth in its entirety, all at once," he says.

Private companies, like Virgin Galactic and Blue Origin, are likely to start shuttling the mega-rich into Earth orbit in the early 2020s. However, Sarah Pearce, deputy director of astronomy and space science at the Commonwealth Scientific and Industrial Research Organisation, suggests it might be a stretch to see moon tourism by the end of the decade.

"I absolutely think we will have space tourism well before that, but it will be suborbital," she explains, pointing to Virgin and Blue Origin as the drivers of this new way to holiday. However, it's Elon Musk's plans that could begin to turn the moon into an attractive -- albeit expensive -- option for lunar tourists over the next five years. Musk and SpaceX plan to ferry Japanese billionaire Yusaku Maezawa and a handful of artists to the moon in 2023, aboard the company's next-gen Starship rocket, for an undisclosed sum of money. Musk has even suggested Starship could get to the moon as early as 2021.

At the 60th anniversary of the Apollo 11 landing in 2029, private citizens will have visited the moon, but we will have only just scratched the surface of what humans can achieve there. Like the 50th anniversary celebrations in 2019, the Apollo 11 milestone will be celebrated by a handful of highly trained scientists and astronauts within a space station and by those making their way down to the lunar poles. As we launch into the next decade -- the 2030s -- our focus shifts to maintaining our presence on lunar soil by taking advantage of the moon's natural resources.

Lunar explorers -- both man and machine -- begin to utilize the moon's resources to maximum effect early in the decade. On the surface and in orbit, astronauts are now priming themselves for an onward journey deeper into the solar system and their first steps on another planet altogether.

"The moon is the proving ground. Mars is the horizon goal," said NASA administrator Jim Bridenstine in March 2019. However, to reach that goal, a number of key technological advances must occur. Chief among them is harnessing the natural resources present on the moon to reduce the costs of off-Earth exploration. This process is known as in situ resource utilization, or ISRU, and it's critical to expanding our capabilities on the moon. Scaling up ISRU will not only require a human touch, but development of artificial intelligence to autonomously work and mine lunar resources.

NASA's Resolve rover would "find, characterize and map ice and other substances in almost permanently shadowed areas." NASA

And the most obvious resource on the craggy face of the moon is the dust and rock that litters the lunar soil. The fine lunar dust can be particularly nasty for human lungs but it is rich in stuff we just can't find as easily on Earth. It's abundant in helium-3, a proposed clean energy source, and its rocks contain an important mineral known as anorthite. Composed of a handful of notable elements, anorthite could be used for life support systems and construction, forming the backbone of a strong lunar manufacturing industry. Most importantly, the rocks are just lying around everywhere.

"You don't need to mine, you don't need to dig tunnels, you don't need to do anything like that," explains Weir. "You just need to scoop them up off the ground."

Collecting and smelting anorthite gives us two key ingredients: oxygen and aluminum. Another abundant lunar mineral, ilmenite, could also be used to extract oxygen and would supply metals such as titanium and iron. Harnessing the power of the sun to power machinery and mining equipment will allow us to pull these valuable elements from the very ground we walk on with minimal disturbance to the natural environment.

Extracting oxygen on the moon is immensely helpful because humans will still need to breathe in 2040, but it also forms a valuable component of rocket fuel. Combining it with hydrogen extracted from water ice deposits found at the lunar poles provides us with propellant, which makes the moon a very attractive spot to stop over as we head deeper into space.

"When you are at the moon, you're most of the way to anywhere, energetically," says Carpenter, invoking a classic quote from science fiction author Robert Heinlein. "So if we have deposits of propellant on the moon, this can be very useful."

But there is a downside. As we begin to visit the moon more frequently, utilizing more and more resources, pressure will mount for greater oversight of human activities on the surface. As many new nations plant their flags in the soil for the first time, our currently optimistic view of a peaceful, prosperous moon devoid of nationalism is likely to be challenged.

The Outer Space Treaty, which governs activities in space, does not prevent exploitation of the moon's ample resources. Michelle Hanlon, a space lawyer, points out that some of the flimsy definitions within the treaty are open to interpretation, complicating how a state may (or may not) be able to claim ownership over areas of the moon. Furthermore, the Moon Treaty, designed to ensure activities on the moon and other celestial bodies conform to international law, is not currently ratified by any of the major spacefaring nations. Neither treaty provides protection for humanity's most important lunar archaeological locations: the six Apollo landing sites.

The site of humanity's first off-Earth exploration: Will we be able to preserve these sites on the moon? NASA

"The lunar landing sites are the ultimate heritage site," says Hanlon, who also founded For All Moonkind, a nonprofit that seeks to preserve space heritage sites. "No site on Earth is this pristine."

"As humans migrate into space and seek to harness its abundant resources, we need to figure out a way to respect the rights and freedoms of all space actors."

By 2040, international agreements will designate the myriad sites of the Apollo landings as "Solar System Heritage Sites" -- the first of their kind. Tranquility Base, the location of Armstrong and Aldrin's first steps, is regarded as a sacred location, protected as stoically as the Pyramids of Giza or the Great Wall of China are on Earth.

A more difficult proposition will be how to reconcile our science objectives with those tailored for exploration. If new sites on the moon, such as the lunar poles, do provide us with some startling evidence of other life in the solar system, we'll be required to rethink our strategies all over again.

While space agencies around the world will busy themselves with science and sustainability on the moon, Mars provides another challenge altogether. Elon Musk's SpaceX is aiming at 2022 for the company's first mission to the red planet, with human landing to occur in 2024. That seems an ambitious goal at present. For SpaceX it requires successful development of Starship and a number of yet-to-be-seen technological improvements that, for instance, provide a source of fuel on the surface of Mars.

It's reasonable to suspect we will have planted our feet on Mars as the decade comes to an end but we'll still be mastering deep space travel. The moon is the best place we have to learn. We'll have scooped up its rock, better understood lunar geology and history, utilized its vast polar caps to supply us with water and rocket fuel, and established a constantly crewed base of operations.

The face of the moon is changing.

As humans begin to truly colonize the surface, we're no longer visitors, but fully fledged residents. Entire stations designed to sustain our presence have sprung up, and international space agencies now have their own colonies: Russia's construction of a lunar base has been 15 years in the making, and China has assembled a village made up of "lunar palaces," rows of 1,600-square-foot, self-sustaining cabins that astronauts will live in year round.

Satellites, like SpaceX's recently launched Starlink, leave streaks across the sky, obscuring our view of the universe. Victoria Girgis/Lowell Observatory

The constant occupation of the moon has allowed scientists to study space in a way not possible on Earth. One of the moon's unheralded resources is a clear, silent sky, bereft of the chaotic noise of human communication. In 2019, Earth's orbit is already filling with satellites, debris and tiny, powerful cubesats constantly beaming data back at the planet. New satellite constellations have caused grief for astronomers on Earth, but lunar orbit is unlikely to experience the same level of congestion. That makes it a perfect spot from which to look out toward the universe.

"The far side of the moon has always been an interesting suggestion to do a very sensitive, low-frequency radio astronomy experiment," says Ilana Feain, a radio astronomer and commercialization specialist at CSIRO in Australia. In the 2040s, the first lunar astronomers have settled in at a radio telescope on the far side of the moon. A set of flat antennas lie across a large swath of the lunar surface, giving us a moon's-eye view of the cosmos for the first time.

"There's no ionosphere on the moon, so you don't have to worry about signals being blocked, and because you're not facing the Earth at any time, you also don't have to worry about all the nasty interference that comes from humanity."

Feain suggests that lunar radio astronomy may be able to unravel some of the great mysteries of the universe and potentially even search for the faint techno-signatures signifying the existence of intelligent life.

Another mystery, closer to home, is how lunar occupation affects the human body. We know long-term stays in space can alter a slew of normal biological processes affecting our bones, heart, brain and eyes.

"The space environment does not offer conditions for which humans were made," says Jennifer Ngo-Anh, team leader of ESA's science in space environments program.

Human bodies evolved to live under the constant force of 1g of gravity, but once we're off Earth, that force is drastically reduced. On the surface of the moon, it's only one-sixth as strong. Then there's the issue of cosmic radiation, which we are largely shielded from on Earth, constantly bombarding us in space -- and we're not sure how damaging it might be.

Part of the solution will be improving our space suits so they're more flexible and provide greater dexterity. With advances in AI and soft robotics, we'll see a proliferation of smartsuits, easily eclipsing the intelligence of modern-day cellphones. With augmented reality overlays built -in and self-healing skins, the suits will become human-shaped support habitats allowing for lengthy exploration on the lunar surface. But what of the layers of skin and bone inside the suit?

Certainly, one of our greatest challenges at the moon will be how we stay healthy.

The Kelly brothers were part of a year-long study to assess how spaceflight affects the human body. Remember: Mark Kelly has an excellent mustache. Scott Kelly does not. Note: This does not make Mark the evil twin. NASA/Robert Markowitz

In 2019, NASA's Twins Study observed how astronaut Scott Kelly's body changed in comparison to his earthbound twin Mark after 340 days in space. The research team showed that Scott's gene expression changed and his DNA was damaged during his stay in low Earth orbit, along with negative changes to his vision. It's hard to draw conclusions from the study group -- it only featured one subject -- but it's rather obvious we're not meant to be zipping around the Earth in giant tin cans.

And those tin cans can become quite lonely. Humans spending extended periods of time on the moon will be among the most isolated and confined in all of human history. Settling on the moon will provide a test-bed for the effects of that lonely existence, teaching us how significantly isolation affects the psyche in space. However, we've been researching those effects at one of Earth's most isolated locations: Antarctica.

"The French-Italian Concordia Station is one of only three research stations on the Antarctic continent that are permanently occupied throughout the entire year," Ngo-Anh says. "A stay on Concordia station resembles a lot the conditions that astronauts will have to face when they are on long-duration exploration missions."

More remote than the space station: Antarctica's Concordia station. ESA/IPEV/PNRA–A. Salam

With the closest neighbor to Concordia 600 kilometers (about 372 miles) to the north, the base is more isolated than the ISS, explains Ngo-Anh. Crews at the station experience four months of total darkness from May through August. In such extreme conditions, the body -- including the mind -- does its best to adapt, but researchers have seen confusion, irritability, depression, insomnia and even mild trance states exhibited by those staying at the station. One crew member told the BBC in 2012 that life changes from "being in technicolor to black and white."

Having spent two decades living on the moon by the end of the 2040s, we're painting a clearer picture of what it means to live in space. Our stations are fitted with centrifuges that allow scientists and astronauts to get their fix of artificial gravity each day and we've become better at dealing with isolation and confinement thanks to advances in communications and development of new augmented and virtual reality platforms. Sick of the dark, barren landscape on the moon? That's OK -- you can slip off to a sunny shoreline in Malta as soon as you strap on a headset.

The moon was new, barren, dark and cold less than 80 years ago. Now, as we hit 2050, it supports human beings all year round in the same way research stations in Antarctica do. Critically, the moon has become the highest-fidelity analogue to recreate deep space exploration missions. The knowledge we gain leading up to the 80th and 90th anniversaries of Apollo 11 gives us both the tools and skills we need to survive on a completely different planet: Mars.

Humanity's first steps on the moon reverberate across the solar system. Our one giant leap in 1969 has become one colossal jump by the time we celebrate the 100th anniversary of Apollo 11, with the lunar landing centennial party an interplanetary affair. Humans on the surface of the Earth, in orbit, on the moon and on the dusty, red plains of Mars toast to the first time humans ever stepped foot outside of planet Earth.

In this decade, travel between low Earth orbit and the Earth is as simple as booking a flight from New York to London -- and reusable rockets from companies like SpaceX and Blue Origin have dramatically reduced costs. However, it's still prohibitively expensive for most to ride a rocket to the moon. Like the Antarctic, the lunar surface remains a place that only a few thousand get to visit each year, and they're mostly scientists and researchers.

There's a grim certainty about living on the moon that we must now confront, however: We are also dying on the moon. Whether by error, malfunction or misunderstanding, and though every effort will be taken to prevent it, the lunar surface will likely become the first celestial body a human being dies on. Those who bravely tread on the moon, hundreds of thousands of miles from home, will come to rest there forever. That, too, will be a new challenge for humanity, which to date has never had to retrieve the bodies of astronauts from space or a distant body. Heads of state will no doubt prepare speeches for such a tragedy, like Richard Nixon did before Apollo 11.

Perhaps the most interesting predictions about the 2060s is how the inevitable technological advances will reshape our societies and cultures. The European Space Agency's James Carpenter explains the economic impact of space exploration is "very significant," noting that all of the money we spend on space also gets spent on Earth. Already, Earth-based industries are presenting exotic business cases for lunar industry based on tweaking their established protocols and practices. The tweaks could be as simple as providing communications to those on the moon or providing solutions to complex problems such as developing water-free ways to mine its subsurface or building intelligent machines that carry out tasks remotely and autonomously.

The social impact will extend even further as more and more humans have a chance to look back at the Earth as it hangs, partially lit, against the black curtain of space. Astronauts on the ISS and during the early exploration missions have reported a cognitive shift in awareness, known as the overview effect, which occurs when you finally view the Earth in relation to the rest of the universe. The reality sinks in: This fragile globe contains all human life that has ever existed. Will such a sight compel us to protect our home? Or make us more inclined to depart it?

Earthrise, taken during the first crewed voyage to the moon. Apollo 8. NASA/Bill Anders

And a bigger question lingers: What will we have to protect by 2069? The planet is in the midst of a climate crisis the likes of which we have never seen, in which rising temperatures threaten lives, rising sea levels threaten cities and rising levels of extinction threaten the biodiversity on Earth.

Click here for To the Moon, a CNET series examining our relationship with the moon from the first landing of Apollo 11 to future human settlement on its surface. Robert Rodriguez/CNET

Many of the scientists and researchers I spoke to were reluctant to make any sweeping predictions about humanity's future on the moon. "I really hope that we've got people back on the moon within a decade," Pearce says, pointing to NASA's Artemis missions and a growing international interest in returning to the moon.

It's difficult -- maybe even crazy -- to try to predict the future of the moon over the next 50 years, but there is one unassailable truth about the human experience: We have an insatiable hunger to know and an unquenchable desire to seek out the truth of our universe. Carl Sagan, one of the most respected astronomers of the 20th century, remarked at the beginning of his acclaimed documentary series Cosmos how the surface of Earth is merely the shore of a vast cosmic ocean. By landing on the moon, he said, humans had waded out, ankle-deep, and found the water inviting.

One hundred years later, we'll have learned to swim, treading further into the unknown and watching the waters of the cosmic ocean rise up to our waist.

It all starts with the moon.