by Michio Kaku
Bezos is producing yet another rocket that will send people into Earth orbit. It is the New Glenn rocket, named after astronaut John Glenn, the first American to orbit the Earth. The rocket will have up to three stages, stand 313 feet tall, and generate 3.8 million pounds of thrust. Although the New Glenn rocket is still being designed, Bezos has dropped hints that he is planning an even more advanced rocket, to be called the New Armstrong, which may go beyond Earth orbit and all the way to the moon.
When he was a child, Bezos dreamed of going into outer space, mainly with the crew of the Enterprise on Star Trek. He would participate in plays based on the TV series, taking on the roles of Spock, Captain Kirk, and even the computer. Upon his high school graduation, a time when most teenagers might fantasize about their first car or the senior prom, he laid out a visionary plan for the next century. He said he wanted to “build space hotels, amusement parks, yachts and colonies for two or three million people orbiting around the earth.”
“The whole idea is to preserve the Earth…The goal [is] to be able to evacuate humans. The planet would become a park,” he wrote. As Bezos saw it, the polluting industrial output of the planet could eventually be moved into space.
To put his money where his mouth is, as an adult, he founded the company Blue Origin to build the rockets of the future. The name of his rocket company refers to the planet Earth, which can be seen as a blue sphere from outer space. The aim is “to open up space travel to paying customers. The vision for Blue is pretty simple,” he says. “We want to see millions of people living and working in space. That’s going to take a long time but I think it’s a worthwhile goal.”
In 2017, he announced a short-term plan for Blue Origin to set up a delivery system for the moon. He envisions a vast operation that, just as Amazon rapidly ships out a variety of products at the click of a button, could deliver machinery, building supplies, and goods and services to the moon. Once considered a lonely outpost in space, the moon would become a bustling industrial and commercial hub, with permanent manned bases and manufacturing.
This loose talk about cities on the moon might normally be dismissed as the ravings of an eccentric. But when it comes from one of the richest people on Earth, who has the ear of the president, Congress, and the editors of the Washington Post, one takes it all quite seriously.
PERMANENT MOON BASE
To help pay for these ambitious projects, astronomers have looked into the physics and economics of mining the moon and noted at least three potential resources worth exploiting.
In the 1990s, an unexpected discovery caught scientists by surprise: the presence of large quantities of ice in the southern hemisphere of the moon. There, in the shadows of large mountain ranges and craters, is a perpetual darkness that is below freezing. The origin of this ice is probably cometary impacts in the early history of the solar system. Comets are mainly made of ice, dust, and rock, so any comet that strikes the moon in one of these shadows might leave a deposit of water and ice. The water, in turn, can be turned into oxygen and hydrogen (which happen to be the principal components of rocket fuel). This could turn the moon into a cosmic gas station. The water could also be purified for drinking purposes or used to create small-scale agricultural farms.
In fact, another group of Silicon Valley entrepreneurs has created a company called Moon Express to begin the process of mining ice from the moon. It is the first company ever to get permission from the government to begin this commercial enterprise. The preliminary target for Moon Express is, however, more modest. The company will begin by putting a lunar rover on the moon that will systematically search for the presence of ice deposits. The company has already raised enough money through private funding to proceed with this mission. With the financing in place, all systems are go.
Scientists have analyzed the moon rocks brought back by the Apollo astronauts and believe there may be other economically significant elements on the moon. Rare earth elements are crucial for the electronics industry but are mostly found in China. (Rare earths are located everywhere in small quantities, but the Chinese rare earth industry makes up 97 percent of the world trade. China has roughly 30 percent of the world’s reserves.) A few years ago, an international trade war almost erupted when Chinese suppliers abruptly raised prices on these key elements, and the world suddenly realized that China had a near monopoly. It is estimated that the supply will begin to be depleted in the coming decades, making it urgent to find alternate sources. Rare earths have been found in moon rocks, so one day it may be cost-effective to extract them from the moon. Platinum is another important element for the electronics industry, and the presence of platinum-like minerals, perhaps left over from ancient asteroid impacts, has also been detected on the moon.
Finally, there is the possibility of finding helium-3, which is useful in fusion reactions. When hydrogen atoms are combined at the extremely high temperatures found in these reactions, the hydrogen nuclei fuse, creating helium, plus large amounts of energy and heat. This excess energy is useful to power machines. However, this process also produces copious quantities of neutrons, which are dangerous. The advantage of the fusion process involving helium-3 is that it instead releases an excess proton, which can be handled more easily and deflected by electromagnetic fields. Fusion reactors are still highly experimental, and so far, none exist on Earth. But if they are successfully developed, helium-3 could be mined from the moon to supply fuel for the fusion reactors of the future.
But this also raises a tricky point: Is it legal to mine the moon? Or to stake a claim there?
In 1967, the United States, Soviet Union, and many other nations signed the Outer Space Treaty, which banned nations from claiming ownership of celestial bodies like the moon. It banned nuclear weapons from Earth orbit and from being placed on the moon or elsewhere in space. The testing of these weapons was also prohibited. The Outer Space Treaty, the first and only one of its kind, holds to this day.
However, the treaty said nothing about private ownership of land or the use of the moon for commercial activities, probably because those who drafted it didn’t believe private individuals would ever be able to reach the moon. But these matters must be addressed soon, especially now that the price of space travel is dropping and billionaires want to commercialize outer space.
The Chinese have announced that they will put their astronauts on the moon by 2025. If they plant their flag, it will largely be symbolic. But what happens if some private developer stakes a claim to the moon after arriving on his or her private spaceship?
Once these technical and political issues are settled, the next question is, What will it be like to actually live on the moon?
LIVING ON THE MOON
Our original astronauts only spent brief periods of time on the moon, usually a few days. To create the first manned outposts, future astronauts would have to spend extended time there. They would need to adjust to lunar conditions, which, as you can imagine, are quite different from the Earth’s.
One factor that limits how long our astronauts can stay on the moon is the availability of food, water, and air, since they would exhaust the supplies that they carry with them within a matter of weeks. In the beginning, everything would have to be shipped from the Earth. Unmanned lunar probes would have to be sent every few weeks to resupply the station. These shipments would become a lifeline for the astronauts, so any accident involving them could present an emergency. Once a moon base is constructed, even a temporary one, one of the first endeavors for the astronauts might be to create oxygen for breathing and for growing their own food. There are a number of chemical reactions that can produce oxygen, and the presence of water creates a ready supply. And this water could also be used in hydroponic gardens to grow crops.
Fortunately, communication with the Earth would not pose much of a problem, since it only takes a little more than a second for a radio signal to reach the Earth from the moon. Apart from a slight delay, astronauts would be able to use their cell phones and the
internet like they do on Earth, so they could be in constant contact with their loved ones and receive the latest news.
Initially, our astronauts would have to live inside the space capsule. When they venture out, the first order of business would be to unfurl large solar panels to harvest energy. Since one lunar day corresponds to one Earth month, any site on the moon has two weeks of daylight followed by two weeks of darkness. So they would need large banks of batteries to store the electrical energy harvested during the two-week “day” for use during the long “night” that follows.
Once on the moon, the astronauts might want to travel to the poles for several reasons. There are peaks in the polar regions where the sun never sets, so a solar farm with thousands of solar panels could create a steady supply of energy without interruption. The astronauts might also take advantage of the deposits of ice in the shadows of large mountain ranges and craters at the poles. It is estimated that six hundred million metric tons of ice may be found in the northern polar region, in a layer that is several yards thick. Once mining operations begin, much of this ice could be harvested and purified for drinking purposes, as well as for oxygen. It is also possible to mine the soil of the moon, which contains a surprising amount of oxygen. In fact, there are about one hundred pounds of oxygen for every one thousand pounds of lunar soil.
The astronauts would have to adjust to the lower gravity on the moon. According to Newton’s theory of gravity, the amount of gravity on any planet is related to its mass. The moon’s gravity is one-sixth that of Earth’s.
This means that moving heavy machinery would be much easier on the moon. And the escape velocity is much lower, so rockets could both land and take off from the moon rather easily. In the future, a busy spaceport on the moon is a distinct possibility.
But our astronauts would have to relearn simple movements, such as walking. Apollo astronauts realized that walking on the moon was quite awkward. They found that the fastest way to maneuver was to hop. Because of the moon’s lower gravity, you can hop much farther than taking a step, and it’s easier to control your motion.
Another issue to contend with is radiation. For missions lasting a few days, it does not pose a major problem. But if the astronauts spend months on the moon, they could accumulate enough exposure to seriously increase their risk of getting cancer. (Simple medical problems could easily escalate into life-threatening situations on the moon. All of the astronauts would have to have first aid training, and a few of them would probably be medical doctors. If, for example, an astronaut has a heart attack or appendicitis on the moon, most likely the doctor would set up a teleconferencing session with specialists on Earth, who would perhaps perform surgery by remote control. Robots could be brought in to do various forms of microsurgery, guided by skillful hands back on Earth.) The astronauts would need daily “weather reports” from astronomers monitoring solar activity. Instead of indicating upcoming thunderstorms, these weather reports would give warning of huge solar flares that send hot plumes of radiation into space. If there is a giant eruption on the sun, the astronauts could be signaled to seek cover. Once the warning is given, astronauts would have several hours before a deadly rain of charged subatomic particles hits the base.
One way to create shelter from radiation might be to dig an underground base within a lava tube on the moon. These tubes, remnants of ancient volcanoes, can be huge, up to a thousand feet across, and would provide adequate protection from radiation from the sun and outer space.
Once the astronauts have erected the temporary shelter, large shipments of machinery and supplies would have to be sent from the Earth to begin construction of the permanent moon base. Shipping prefabricated materials and inflatable items could speed up this process. (In the movie 2001, astronauts live in huge, modern underground lunar bases, which contain landing platforms for rockets and serve as headquarters to coordinate lunar mining operations. Our first lunar headquarters may not be as comprehensive, but the vision presented in the movie may be realized before too long.)
In building these underground bases, inevitably you will want the ability to manufacture and repair machine parts. Although large equipment such as bulldozers and cranes would have to be sent from the Earth, 3-D printers could fabricate small plastic machine parts on-site.
Ideally, factories would be established to forge metal. But building a blast furnace is impossible, since there is no air to feed the furnace. However, experiments have shown that lunar soil, when heated by microwaves, can be melted and fused to make rock-hard ceramic bricks, which could be the basic building blocks for the entire moon base. In principle, all of the infrastructure could be made of this material, which can be harvested directly from the soil.
LUNAR RECREATION/ENTERTAINMENT
Lastly, there has to be a source of entertainment for the astronauts, a way to blow off steam and relax. When Apollo 14 landed on the moon in 1971, NASA officials did not know that commander Alan Shepard had secretly smuggled a six-iron golf club into the space capsule. They were surprised when he proceeded to take out the club and hit a golf ball two hundred yards on the lunar surface. This was the first and only time someone engaged in a sports activity on another celestial body. (A replica of the golf club is now in the Smithsonian National Air and Space Museum in Washington, D.C.) Lunar sports would pose a particular challenge due to the lack of air and low gravity. But they will also give rise to some remarkable feats.
On Apollo 15, 16, and 17, our astronauts rode the Lunar Roving Vehicles over the dusty surface, each traveling between seventeen and twenty-two miles. Not only was this a valuable scientific mission, it was also a thrilling expedition as they looked out at majestic craters and mountain ranges, knowing that they were the first people ever to see these stunning sights. In the future, riding dune buggies will not only accelerate the survey of the lunar surface, the installation of solar panels, and the construction of the first lunar station, it will serve as a type of recreation. It may perhaps even make possible the first races on the moon.
Lunar tourism and exploration could become popular recreational activities as people discover the wonders of an alien landscape. Given the low gravity, hikers would be able to trek over long distances without tiring. Mountain climbers would be able to rappel down steep mountainsides with little effort. And from the top of craters and mountain ranges, they would have an unprecedented panorama of the lunar landscape, literally untouched for billions of years. Spelunkers who love to explore caves will be excited to investigate the network of gigantic lava tubes crisscrossing the moon. On the Earth, caves were carved out by underground rivers and contain evidence of ancient water flows in the form of stalactites and stalagmites. But on the moon, there are no appreciable deposits of liquid water. The moon’s caves were instead carved out of the rock by molten lava flows. They would look completely different from the caverns we see on Earth.
WHERE DID THE MOON COME FROM?
Once mining operations successfully exploit the resources found on the surface of the moon, we will inevitably turn our eye to the riches that may lie deep within it. Uncovering them would change the economic landscape, as the accidental and unexpected discovery of oil on Earth did. But what is the interior of the moon like? To answer this, we have to consider the question, Where did the moon come from?
The origin of the moon has fascinated humanity for millennia. Because the moon rules the night, it has often been associated with darkness or madness. The word lunatic comes from luna, the Latin word for moon.
Ancient mariners were fascinated by the connection between the moon, the tides, and the sun, and correctly ascertained that there is a close correlation between all three.
The ancients noticed another curious fact: you only see one side of the moon. Think of all the times you’ve looked at the moon, and you realize you’re always seeing the same face.
It was Isaac Newton who finally put all the puzzle pieces together. He calculated that the tides are caused by the gravitational pull of the m
oon and the sun on the Earth’s oceans. His theory indicated that the Earth creates tidal effects on the moon as well. Since the moon is made of rock and has no oceans, it is actually being squeezed by the Earth, and this force causes it to bulge slightly. At one time, it tumbled in its orbit around the Earth. Eventually, this tumbling slowed down, until the spinning of the moon was locked to the Earth, so that one side of it always faced us. This is called tidal locking, and it happens throughout the solar system, including for moons of Jupiter and Saturn.
Using Newton’s laws, you can also determine that tidal forces are causing the moon to slowly spiral away from the Earth. Its orbital radius increases by about 1.6 inches per year. This small effect can be measured by shooting laser beams to the moon—our astronauts left a mirror behind to help with this experiment—and then calculating the time it takes for the beams to bounce back to Earth. The round trip takes only about two seconds, but this number is gradually increasing. If the moon is spiraling away, then, by running the videotape backward, we can estimate its past orbit.
A quick calculation shows that the moon separated from the Earth billions of years ago. And modern evidence indicates that 4.5 billion years ago, not long after the Earth was formed, there was a cosmic impact between the Earth and a large asteroid of some sort. This asteroid, which we call Theia, was about the size of Mars. Computer simulations have given us dramatic insight into this explosion, which gouged out a huge chunk of the Earth and propelled it into space. But because the impact was more of a glancing blow than a direct strike, it didn’t take much of the interior iron core of the Earth. As a result, the moon, while it does contain some iron, has no significant magnetic field because it lacks a molten iron core.