On a cold December night, as the temperature dove near 20 degrees Fahrenheit (minus 7 degrees Celsius), I ventured into the observatory that Lowell built for himself in the small city of Flagstaff, Arizona. As a guest of the observatory, I got to look through the twenty-four-inch (sixty-one-centimeter) lens on the giant refractor telescope that the firm of Alvan Clark & Sons built for Lowell in 1896. Mars was in the heavens as the attendant swung the telescope about the rounded dome of the observatory. It was a couple of hours past sundown as I gazed through the fine instrument, trying to find the so-called canali Lowell had everybody excited about.
It was difficult to make out any canals. The planet’s craters earlier had been clear and sharp, but the canals looked iffy. Particularly when you knew that modern high-resolution mapping of the Martian surface by spacecraft showed no such features. Many felt the canals were an optical illusion, perhaps what one would see after staring through the telescope long enough and late enough. But the Panama and Suez Canals were built in the decades leading up to Lowell’s discoveries, and perhaps he felt that everyone must have been building canals.
Nevertheless, he and his assistants spent more than a decade mapping a system of hundreds of canals on the surface of Mars. His telescope was one of the finest made in its day, but had nowhere near the resolution that today’s telescopes offer. An infrared spectrogram of Mars taken at the Mount Wilson Observatory near Los Angeles in the 1960s revealed that the Red Planet, as Mars was called for its visible reddish hue, had extremely low atmospheric pressure. The pressure on Mars was about 4.5 millimeters of mercury, compared to 760 millimeters of mercury on Earth. At 4.5 millimeters of pressure, water acts like dry ice. At its melting point it changes directly from a solid to a gaseous state. It made Percival Lowell’s idea of a system of canals on Mars impossible. Water couldn’t flow on the surface of Mars.
Yet photographs of the surface of Mars, taken by the Mariner orbital mission as early as 1971–72, as well as photos taken by the Viking missions, show that the planet’s ancient surfaces are marked with branching networks of valleys that clearly resemble river-and streambeds on Earth. In 2008 the Phoenix landed successfully on the north pole of Mars and found pure water ice. Was Lowell at least partially correct?
The fourth planet from the sun is more like Earth than any other body in our solar system. The surface of Mars is more rugged, as it is older and less subject to repair. Mars has dry-ice fields, craters, volcanoes, floodplains, canyons, chasms, and tall mountains. Olympus Mons stands about 16 miles (25 kilometers) above the Martian surface and covers an area 374 miles (624 kilometers) in diameter, about the size of the state of Arizona. The Valles Marineris is over 1,850 miles (3,000 kilometers) long and covers about one-fifth of the circumference of the planet. The Grand Canyon on Earth is only about 500 miles (800 kilometers) long.
Mars has long attracted the attention of stargazers, since it is often considered the closest place we could run to if life grew inhospitable on Earth. It could also be a jumping-off station to the mineral-rich asteroids that orbit nearby. With its low gravity, Mars might prove to be a springboard to distant stars in our galaxy. Mars Odyssey, in orbit around Mars since 2001, used an infrared camera and a gamma ray spectrometer to map the content of the Martian surface, finding large regions near the poles where the soil had over 60 percent water ice by weight.
Scientists believe these watery observations are proof that Mars once had a warm, wet atmosphere that was suitable for life. Early Mars had a lot more CO2 in its atmosphere than it does today, and that produced a considerable greenhouse gas effect and a much milder climate. These conditions persisted on Mars about four billion years ago, close to the point where life evolved on Earth. Could life have evolved on Mars about the same time? Is life on other planets a possibility? With so many millions of stars and millions of planets around them, how could we be the only one?
A day on Mars is similar to one on Earth, being twenty-four hours and thirty-seven minutes long. Mars rotates on its axis and has four seasons, but since the Martian year is about 669 days, winter, spring, summer, and fall are about twice as long as those seasons on Earth. The present-day Martian environment would be a little rough for humans without a good space suit. Daytime temperatures on Mars can get up to 63 degrees Fahrenheit (17 degrees Celsius), but at night they dive down to minus 130 degrees Fahrenheit (minus 90 degrees Celsius). It would be an inhospitable place for a moonlit walk, despite the fact that Mars has two moons.
The question of whether there was ever life on Mars has been an ongoing puzzle for scientists. In 1976, the National Aeronautics and Space Administration (NASA) sent Viking 1 to the Chryse Plains on Mars with a few experiments NASA hoped would answer the life question. The Gas Exchange Experiment was set up to douse Martian soil with “chicken soup,” a nutrient-rich solution that, when added to the soil, might make something breathe. On July 20, Viking 1 set down and extended an arm out of the landing craft, scooped up some soil, and gave it some soup. And as soon as the soil tasted the concoction, there was a violent eruption of oxygen.
But other experiments didn’t yield similar results. Scientists speculated that the surface of Mars might be covered with “superoxides” formed by intense UV radiation that had bombarded the surface. These superoxides had reacted to the water in the soup and gave off oxygen. “It’s the same as when you pour hydrogen peroxide on a cut,” says Christopher McKay, a planetary scientist at NASA’s Ames Research Center. “It fizzles and eats up all the organics present.”
A more recent exploration by the Curiosity rover in 2013 analyzed a powdered sample of soil and found some promise. Only a half mile from the landing spot in the middle of the three-mile- (five-kilometer-) high Gale Crater, Curiosity sampled a rock that contained sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon—a sampling of the major ingredients of life on planet Earth.
In 2011 the Mars Reconnaissance Orbiter found seasonal streaks that formed and disappeared on a Martian slope and may have been the result of underground water ice that thawed and flowed in the Martian spring. Much of Mars’s water is held in permafrost soils or ice. Robert Zubrin, author (with Richard Wagner) of The Case for Mars: The Plan to Settle the Red Planet and Why We Must, says, “Current knowledge indicates that if Mars were smooth and all its ice and permafrost melted into liquid water, the entire planet would be covered with an ocean over 100 meters deep.”
Mars may once have had a warm and wet climate suitable for the origins of life. In their first billion years or so, both Mars and Earth had carbon dioxide atmospheres and were covered with water.
We know that life evolved on our planet, but did it evolve on Mars? Is life a million-to-one long shot that could hardly occur anywhere else, or is it a natural occurrence of certain environmental conditions? If we found living organisms or simple fossils on Mars, it might mean that the universe is full of life. And that would be big indeed. It could perhaps be the escape hatch for man.
The greatest hurdle to the continued exploration and space station development on Mars is, like many things, money. Where does one get enough? When John F. Kennedy launched the Apollo program, which sent men to the moon, the US and Russia were in the middle of the Cold War, and competition and national pride were behind the big push to the moon. But the Cold War days are gone, and nothing like that has arisen to move the Mars program forward. Some say we should wait for technology to advance, to reinvent itself, but Zubrin says time is a-wasting. He feels we can get to Mars with what we’ve got: technologies based on Saturn V rockets from the Apollo days with engines and boosters developed during the space shuttle era.
Mars is a bit out there. At its closest orbital position, it is around 38 million miles (56 million kilometers) distant. The best time to launch a trip from Earth to Mars would be when the planets are at their maximum distance. Over the long trip, eventually the two planets would come closer together, and the trip would then be made over the smallest distance.
Then there’s th
e problem of gas. Zubrin feels that it’s too difficult to go to Mars and return home with enough gas to make the round trip. One of his most daring proposals is that we get our fuel not from Earth but from Mars. He believes that we need only carbon and oxygen from Mars and a little bit of hydrogen (about 5 percent) that we could bring from Earth. Carbon dioxide could be pulled straight out of the Martian air, which is 95 percent CO2. Take a jar and fill it with activated carbon or other suitable material and set it out in the supercold Mars night. With a nighttime chill of minus 130 degrees Fahrenheit (minus 90 degrees Celsius), the material will soak up 20 percent of its weight in CO2. When the sun comes back up, the material will warm up and we will generate high-carbon gas.
The idea is to send the unmanned apparatus to Mars, let it process the fuel first, and then send the manned mission when the gas station is full and in place. The first missions might have enough gas to go both ways, but the extra weight would require additional thrust, and if we can make rocket fuel from Martian air, we’ll be way ahead of the game.
Once we got enough CO2, we could mix it with the hydrogen we brought from Earth and get methane and water from the combination. The water produced can be split into oxygen, which could be stored, and hydrogen, which could be recycled back into the methane-producing process. The equipment necessary for methane production would comprise three reactors, each three feet (one meter) long and five inches (twelve centimeters) in diameter.
Scientists think that the first missions could be dangerous, and Zubrin agrees but thinks that a small crew would still be best. It would include two mechanics—or flight engineers, if you will—a biologist, and a geologist, four people in all. That would provide two scientist/mechanic teams, one at the base camp and one out in the field. The geologist would explore the planet’s geological history while evaluating the planet’s fuel and geological resources. The biologist could address the question of life on Mars while evaluating the soil and the environment for their ability to support greenhouse agriculture.
We could make plastics out of hydrogen and CO2. Mars soil is full of clay, so we could make great ceramics for pottery, including pots, dishes, and cups, as well as bricks. One of the most accessible materials on Mars would be iron. It is this ore in the soil that gives Mars its reddish color. Carbon, manganese, phosphorus, and silicon are common and could be mixed with iron to make steel. Mars also has a lot of aluminum.
Silicon is plentiful, too. This could be used to make photovoltaic panels, which could generate power, though getting enough will be a problem in the early years. Though probably not a popular idea, Zubrin thinks it would be necessary to import a nuclear reactor from Earth to meet the energy demands of the base’s earlier years. Once the base is well established, solar, wind, or geothermal power could be added to the mix. But nuclear power would be necessary to get things going, unless one wants to eat up the fuel needed to get home.
Geothermal power would be an attractive source, and perhaps an alternative to a nuclear reactor. Geothermal power is the fourth-largest source of power on Earth, behind combustion, hydroelectric, and nuclear. The idea is to utilize the heat of the inner planet to boil liquids and to use the steam produced to run a generator. If explorers found a geothermal heat source near underground water, that would be an inviting location for a Martian base.
Mars has other precious materials, including deuterium, the heavy isotope of hydrogen, a key element of nuclear power. There is about five times as much deuterium on Mars as there is on Earth, and a kilo of deuterium is worth about $10,000.
But perhaps the biggest attraction to building a station is the possibility of interplanetary trade. Mars is close to the main asteroid belt that circles the sun between Mars and Jupiter. Asteroids contain large amounts of high-grade metal ore, making them attractive for commerce. An average asteroid about one kilometer in diameter could hold about 200 million metric tons (10 percent larger than a US ton) of iron, 30 million metric tons of nickel, 1.5 million metric tons of cobalt, and 7,500 metric tons of platinum, worth about $150 billion for the platinum alone.
A Mars station could be a staging ground for travel to other places in the solar system and beyond. Under Zubrin’s plan, the modules that house the Earth-to-Mars portion of the trip could be repurposed as the first houses of a new Martian settlement. Bricks fashioned from the finely ground, claylike dust that covers the surface of the planet could be used for additional support. These modules could be used to construct Roman-style vaults or large atriums.
Houses would have to be built underground. The Martian inhabitants would need at least 8 feet (2.5 meters) of dirt on top of their houses to properly pressurize them and to protect their inhabitants from the wide swings in temperature. Large plastic inflatable structures could be used as temporary housing while underground structures and aboveground greenhouses are being built for eventual crop growth.
Mars’s atmosphere is sufficiently dense to protect its initial builders and farmers from solar flares, and there are other beneficial qualities as well. Martian sunlight, though less than that on Earth, is enough for photosynthesis. Add some CO2 to your greenhouse and that could make up for the diminished sunlight. Martian soil is richer than that on Earth. It may need extra nitrogen, but that can be synthesized as it is here. Raising cattle, sheep, and goats would be inefficient, since it would take five times as much grain to feed the cattle as it takes to feed humans directly, so Mars astronauts might have to forgo steak in the early years.
The first Martian task would be to find water. Evidence from past missions says it’s there. For manned missions, it might work to bring some more of the hydrogen (H) component from Earth to make H2O, but once the building phase ensues and the Mars population begins to grow, water would have to take precedence. A geothermal source with water would be great. Let’s just hope it’s not too close to the poles. Observations by the Mars Reconnaissance Orbiter in 2009 reported pure water ice in relatively new craters located between 43 and 56 degrees north latitude, and that is an area of relatively temperate Martian climate.
Though the sum total of Zubrin’s suggestions may sound daunting, the technological hurdles we’ve surmounted in just the last century make anything seem possible. There is an adventuresome spirit in man that could make it happen. Think of Captain Robert Scott and his expedition to the South Pole. Hopefully a trip to Mars might have a happier ending.
As we look to the future, Mars might also be a good place to understand our past and perhaps even the riddle of first life. Two-thirds of the surface of Mars is 3.8 billion years or older. And Mars is a lot less volcanic than Earth. Since it is small, less than twice the size of our moon, the Red Planet cooled more quickly than Earth and developed a thick, immovable crust. The surface of Earth is constantly renewed as the continental plates collide, sink, and are rebuilt, a product of plate tectonics. Earth’s fossil record has yet to cough up the earliest steps that led to life, the appearance of cells, photosynthesis, and DNA. The hope is that Mars, whose crust has remained stagnant for aeons—leaving any fossils far more intact—might be a better place to understand the formation of life than here on Earth.
The draw here is that MIT and Harvard researchers think it’s possible that all life on Earth is descended from microorganisms on Mars that were carried aboard meteorites that traveled to Earth. The climates on Mars and Earth were once much more similar, so life that was viable on one planet might also survive on the other. Also, an estimated one billion tons of rock have traveled from Mars to Earth, blasted loose by asteroid impacts and then hurled through interplanetary space before striking Earth’s surface. And microbes have demonstrated an ability to survive the initial shock of such an impact, as well as the fortitude to journey through space and arrive on another planet.
So what about current life on Mars? Though things look a little rough on the Martian surface, could life exist underneath? Scientists have been looking at the deep and dismal corners of our planet to find out just how tough an environment li
fe can withstand. I interviewed Bob Wharton, who passed away in 2012: he was a rugged researcher who studied karate under Chuck Norris and discovered life in Antarctica at the bottom of frozen lakes. At Lake Hoare in Taylor Valley, about eight hundred miles from the South Pole, his crew spent a half day melting a hole in the twenty-foot-thick crust of ice before climbing in and descending to the lake bottom. What they found were bizarre microbial mats—tissuey structures that are pigmented green, red, and purple to catch the limited light. “It’s a fairly advanced form of life,” said Wharton. “You’ve got a cell wall, and you’ve got DNA inside the cell to pass on information to its offspring. It’s not elephants, but it’s a big step in the evolution of biology.”
Despite a mean temperature of minus 28 degrees Fahrenheit (minus 33 degrees Celsius) above the ice, underneath everything’s toasty and above freezing. The ice provides what scientists call “thermal buffering.” Wharton also looked for life on the 14,179-foot (4,322-meter) volcanic summit of Mount Shasta in the state of California. He sampled microorganisms there in acid hot springs. “The water would have burnt holes in my clothes,” said Wharton, “but microorganisms were thriving.” Could life survive in similar environments on Mars?
The Next Species: The Future of Evolution in the Aftermath of Man Page 23
