by Michio Kaku
Then, there are the micrometeors, which can tear the outer hull of a spacecraft. Close examination of the space shuttle reveals the impact of numerous micrometeorites on its tiled surface. The force of a micrometeor the size of a postage stamp traveling at forty thousand miles per hour would be enough to rip a hole in the rocket and cause rapid depressurization. It may be wise to separate space modules into different chambers, so that a punctured section can be rapidly sealed off from the others.
Psychological difficulties will present a different kind of obstacle. Being locked up in a tiny, cramped capsule with a small group of people for an extended period of time will be challenging. Even with a battery of psychological tests, we cannot definitively predict how—or whether—people will cooperate. Ultimately, your life may depend on someone who gets on your nerves.
GOING TO MARS
After months of intense speculation, in 2017 NASA and Boeing finally revealed the details of the plan to reach Mars. Bill Gerstenmaier, of NASA’s Human Exploration and Operations Directorate, revealed a surprisingly ambitious timetable for the steps necessary to send our astronauts to the Red Planet.
First, after years of testing, the SLS/Orion rocket will be launched in 2019. It will be fully automatic, carrying no astronauts, but will orbit the moon. Four years later, after a fifty-year gap, astronauts will finally return to the moon. The mission will last three weeks, but it will just orbit around the moon, not land on the lunar surface. This is mainly to test the reliability of the SLS/Orion system rather than to explore the moon.
But there is an unexpected twist to NASA’s new plan that surprised many analysts. The SLS/Orion system is actually a warm-up act. It will serve as the main link by which astronauts will leave the Earth and reach outer space, but an entirely new set of rockets will take us to Mars.
First, NASA envisions building the Deep Space Gateway, which resembles the International Space Station, except it is smaller and orbits the moon, not the Earth. Astronauts will live on the Deep Space Gateway, which will act as a refueling and resupply station for missions to Mars and the asteroids. It will be the basis for a permanent human presence in space. Construction of this lunar space station will begin in 2023 and it will be operational by 2026. Four SLS missions will be required to build it.
But the main act is the actual rocket that will send astronauts to Mars. It is an entirely new system, called the Deep Space Transport, which will be constructed mainly in outer space. In 2029, the Deep Space Transport will have its first major test, circling around the moon for three hundred to four hundred days. This will provide valuable information about long-term missions in space. Finally, after rigorous testing, the Deep Space Transport will send our astronauts to orbit Mars by 2033.
NASA’s program has been praised by many experts because it is methodical, with a step-by-step plan to build an elaborate infrastructure on the moon.
However, NASA’s plan stands in sharp contrast to Musk’s vision. NASA’s plan is carefully fleshed out and involves the creation of a permanent infrastructure in lunar orbit, but it is slow, perhaps taking a decade longer than Musk’s plan. SpaceX bypasses the lunar space station entirely and blasts directly to Mars, perhaps as early as 2022. One drawback, however, of Musk’s plan is that the Dragon space capsule is considerably smaller than the Deep Space Transport. Time will tell which approach or combination of approaches is better.
FIRST TRIP TO MARS
Because more details are being revealed concerning the first Mars mission, it is now possible to speculate on the steps necessary to reach the Red Planet. Let us trace how NASA’s plan may unfold over the next few decades.
The first people on the historic mission to Mars are probably alive today, perhaps learning about astronomy in high school. They will be among the hundreds of people who are expected to volunteer for the first mission to another planet. After rigorous training, perhaps four candidates will be carefully chosen for their skills and experience, probably including a seasoned pilot, an engineer, a scientist, and a doctor.
NASA’s Deep Space Gateway will orbit the moon and serve as a fuel and supply station for missions to Mars and beyond. Credit 2
Sometime around 2033, after a series of anxious interviews with the press, they will finally climb aboard the Orion space capsule. Although the Orion has 50 percent more room than the original Apollo capsule, things will still be cramped inside, but it doesn’t matter, since the trip to the moon will last only three days. When the spaceship finally blasts off, they will feel vibrations from the intense burning of rocket fuel from the SLS booster rocket. The entire trip so far looks and feels very similar to the original Apollo mission.
But here, the similarity ends. From this point, NASA envisions a radical departure from the past. As they enter lunar orbit, the astronauts will see the Deep Space Gateway, the world’s first space station orbiting the moon. The astronauts will dock with the Gateway and rest a bit.
They will then transfer to the Deep Space Transport, which looks like no other spacecraft in history. The spaceship and crew’s quarters resemble a long pencil, with an eraser at one end (which contains the capsule in which the astronauts will live and work). Along the pencil, there are series of gigantic arrays of unusually long, narrow solar panels, so, from a distance, the rocket begins to resemble a sailboat. While the Orion capsule weighs about twenty-five tons, the Transport weighs forty-one.
The Deep Space Transport will be their home for the next two years. This capsule is much bigger than the Orion and will give astronauts enough room to stretch a bit. This is important, since they have to exercise daily to prevent muscle and bone loss, which could cripple them when they reach Mars.
Once on board the Deep Space Transport, they will turn on the rocket’s engines. But instead of being jolted by a powerful thrust and watching gigantic flames shoot from the back of the rocket, the ion engines will accelerate smoothly, gradually building up speed. Staring outside their windows, the astronauts will only see the gentle luminous glow of hot ions being steadily emitted from the ship’s engines.
The Deep Space Transport uses a new type of propulsion system to send astronauts through space, called solar electric propulsion. The huge solar panels capture sunlight and convert it to electricity. This is used to strip away the electrons from a gas (like xenon), creating ions. An electric field then shoots these charged ions out one end of the engine, creating thrust. Unlike chemical engines, which can only fire for a few minutes, ion engines can slowly accelerate for months or even years.
Then begins the long, boring trip to Mars itself, which will take about nine months. The main problem facing the astronauts is boredom, so they will have to constantly exercise, play games to keep alert, do calculations, talk to their loved ones, surf the web, etc. Other than routine course corrections, there is not much else to do during the actual voyage. Occasionally, however, they might be required to do some spacewalks in order to make minor repairs or replace worn parts. As the journey progresses, however, the time it takes to send radio messages to Earth gradually increases, eventually reaching about twenty-four minutes. This may prove a bit frustrating for the astronauts, who are used to instantaneous communication.
As they gaze out their windows, they will gradually see the Red Planet come into focus, looming in front of them. Activity aboard the spaceship will rapidly quicken as the astronauts begin to make preparations. At this point, they will fire their rockets to slow their spacecraft down so they can gently enter into orbit around Mars.
From space, they will see an entirely different panorama than seen on the Earth. Instead of blue oceans, green tree-covered mountains, and the lights of cities, they will see a barren, desolate landscape, full of red deserts, majestic mountains, gigantic canyons that are much larger than the ones on Earth, and huge dust storms, some of which can engulf the entire planet.
Once in orbit, they will enter the Mars capsule and separate from the main spacecraft, which will continue to orbit the planet. As thei
r capsule enters into the Martian atmosphere, the temperature will rise dramatically, but the heat shield will absorb the intense heat generated by air friction. Eventually, the heat shield will be ejected, and the capsule will then fire its retrorockets and slowly descend onto the surface of Mars.
Once they exit the capsule and walk on the surface of Mars, they will be pioneers opening up a new chapter in the history of the human race, taking a historic step toward realizing the goal of making humanity a multiplanet species.
They will spend several months on the Red Planet before the Earth is in the right alignment for the return trip. This will give them time to scout the terrain, do experiments, such as looking for traces of water and microbial life, and set up solar panels for power. One possible objective might be to drill for ice in the permafrost, since underground ice may one day become a vital source of drinking water, as well as oxygen for breathing and hydrogen for fuel.
After their mission is complete, they will go back into their space capsule and then blast off. (Because of Mars’s weak gravity, the capsule requires much less fuel than it would to leave the Earth.) They will dock with the main ship in orbit, and then the astronauts will prepare for the nine-month journey back to the Earth.
Upon their return, they will splash down somewhere in the ocean. Once back on terra firma, they will be celebrated as heroes who took the first step toward establishing a new branch of humanity.
As you can see, we will face many challenges on the road to the Red Planet. But with the public’s enthusiasm, and with the commitment of NASA and the private sector, it is likely that we will achieve a manned mission to Mars in the next decade or two. This will open up the next challenge: to transform Mars into a new home.
I think that when humans get around to exploring and building cities and towns on Mars, it will be viewed as one of the great times of humanity, a time when people set foot on another world and had the freedom to make their own world.
—ROBERT ZUBRIN
5 MARS: THE GARDEN PLANET
In the 2015 movie The Martian, the astronaut played by Matt Damon faces the ultimate challenge: to survive alone on a frozen, desolate, airless planet. Accidentally left behind by his fellow crewmates, he has only enough supplies to last a few days. He must summon all his courage and know-how to last until a rescue mission can reach him.
The movie was realistic enough to give the public a taste of the difficulties Martian colonists would encounter. For one, there are the fierce dust storms, which engulf the planet with a fine red dust that resembles talcum powder and almost tipped over the spacecraft in the movie. The atmosphere is almost entirely made of carbon dioxide, and the atmospheric pressure is only 1 percent that of the Earth, so an astronaut would suffocate within a few minutes if exposed to the thin Martian air, and his blood would begin to boil. To produce enough oxygen to breathe, Matt Damon has to create a chemical reaction in his pressurized space station.
And since he is rapidly running out of food, he has to grow his own plants in an artificial garden. To fertilize the crops, he has to use his own waste.
Bit by bit, the astronaut in The Martian takes the excruciating steps necessary to create an ecosystem on Mars that is capable of sustaining him. The movie helped to capture the imagination of a new generation. But the fascination with Mars actually has a long and interesting history that stretches back to the nineteenth century.
In 1877, Italian astronomer Giovanni Schiaparelli noticed strange linear markings on Mars that seemed to be formed by natural processes. He called the markings “canali,” or channels. However, when the Italian was translated into English, the i was dropped and the term became “canals,” which has an entirely different meaning: they are artificial, not natural. A simple mistranslation gave way to an avalanche of speculation and fantasy, sparking the “man from Mars” myth. The wealthy, eccentric astronomer Percival Lowell began to theorize that Mars was a dying planet and that the Martians had dug the canals in a desperate attempt to transport water from the polar ice caps to irrigate their scorched fields. Lowell would dedicate his life to proving his conjecture, using his considerable private fortune to build a state-of-the-art observatory in Flagstaff in the Arizona desert. (He never did prove the existence of these canals, and years later, space probes would show that the canals were an optical illusion. But the Lowell Observatory scored successes in other areas, contributing to the discovery of Pluto and providing the first indication that the universe was expanding.)
In 1897 H. G. Wells wrote The War of the Worlds. The Martians in the novel plan to annihilate humanity and “terraform” the Earth so that its climate becomes like that of Mars. The book gave rise to a new literary genre—you could call it the “Mars attacks” genre—and the idle, esoteric discussions of professional astronomers suddenly became a matter of survival for the human race.
On the day before Halloween in 1938, Orson Welles took excerpts from the novel to create a series of short, dramatic, realistic radio broadcasts. The program was presented as if the Earth was actually being invaded by hostile Martians. Some people began to panic, hearing updates on the invasion—how the armed forces had been overwhelmed by death rays, and how the Martians were converging on New York City in giant tripods. Rumors from terrified listeners spread rapidly across the country. In the aftermath of this chaos, the major media vowed never again to broadcast a hoax as if it were real. This ban continues today.
Many people were caught up in Martian hysteria. The young Carl Sagan was enthralled by novels about Mars, such as the John Carter of Mars series. In 1912, Edgar Rice Burroughs, famous for his Tarzan novels, dabbled in science fiction by writing about an American soldier during the Civil War who is transported to Mars. Burroughs speculated that John Carter would become a superman because of the low gravity on Mars relative to Earth. He would be able to jump incredible distances and outfight the alien Tharks to save the beautiful Dejah Thoris. Cultural historians believe that this explanation for the superpowers of John Carter formed the basis of the Superman story. The 1938 issue of Action Comics in which Superman first appears attributes his superpowers to the weak gravity of the Earth compared to his native Krypton.
LIVING ON MARS
Taking up residence on Mars may sound romantic in science fiction, but the realities are quite daunting. One strategy for prospering on the planet is to take advantage of what is available, such as ice. Since Mars is frozen solid, all you would have to do is dig a few feet until you hit the permafrost. Then you could excavate the ice, melt it, and purify it for drinking water, or extract oxygen for breathing and hydrogen for heating and rocket fuel. For protection against radiation and dust storms, colonists might have to dig into the rock to build an underground shelter. (Because the atmosphere of Mars is so thin and its magnetic field is so weak, radiation from space is not absorbed or deflected as it is on Earth, so this is a real problem.) Or it could be advantageous to set up the first Martian base in a gigantic lava tube near a volcano, as we discussed doing on the moon. Given the prevalence of volcanoes on Mars, it is likely such tubes would be plentiful.
A day on Mars is roughly the same duration as a day on Earth. The tilt of Mars with respect to the sun is also the same as Earth’s. But settlers would have to get used to the gravity on Mars, which is only 40 percent of the gravity on Earth, and, as on the moon, they would have to exercise vigorously to avoid muscle and bone loss. They would also need to contend with the brutally cold weather and would be in a constant struggle to avoid freezing to death. The temperature on Mars rarely exceeds the freezing point of water, and after the sun goes down, it can plunge to as low as -127 degrees Celsius or -197 degrees Fahrenheit, so any power failure or blackout could prove life threatening.
Even if we can send the first manned mission to Mars by 2030, because of these obstacles it may take until 2050 or beyond to compile sufficient equipment and supplies to create a permanent outpost on the planet.
MARTIAN SPORTS
Because of the vital
importance of exercise to prevent muscle deterioration, astronauts on Mars will necessarily have to engage in vigorous sports, where they will find, much to their delight, that they have superhuman abilities.
But this also means that sports arenas would have to be completely redesigned. Because the gravity on Mars is a little bit more than one-third the gravity on Earth, a person can in principle jump three times higher on Mars. A person would also be able to throw a ball three times farther on Mars, so basketball courts, baseball diamonds, and football fields would have to be enlarged.
Furthermore, the atmospheric pressure on Mars is about 1 percent that of Earth, meaning that the aerodynamics of baseballs and footballs are drastically modified. The main complication is the precise control of the ball. On Earth, athletes are paid millions of dollars because of their uncanny ability to control the motion of a ball, which takes years of practice. This skill has to do with their ability to manipulate the ball’s spin.
When a ball moves through the air, it creates turbulence in its wake, small eddy currents that cause the ball to swerve slightly and slow down. (For a baseball, these eddy currents are created by the stitching on the ball, which determines its spin. On a golf ball, it is caused by the dimples on its surface. For soccer balls, it is due to the juncture between the plates on its surface.)
Football players throw the ball so that it spirals rapidly in the air. Spinning reduces the eddy currents on the ball’s surface, so it can more accurately slice through the air and travel much farther without tumbling. Also, because it is spinning rapidly, it is like a small gyroscope and hence points steadily in one direction, which keeps the football moving in the correct path and makes it easier to catch.
Using the physics of airflow, it is also possible to show that many of the myths concerning throwing a baseball are true. For generations, baseball pitchers have claimed that they can throw knuckleballs and curveballs, which allows them to control the ball’s trajectory, seemingly in violation of common sense.