The Sirens of Mars

by Sarah Stewart Johnson

  The Soviets had been trying to reach Mars for five years. In space exploration as in all things, they were a formidable adversary. In 1960, their first pair of missions had coincided with Premier Nikita Khrushchev’s visit to the United Nations General Assembly in New York. He’d commissioned models of the Mars probes and brought them along to show the world. Less than two months earlier, his lead rocket engineer had launched into space the first sentient beings that returned safely to Earth: two dogs, a gray rabbit, forty mice, two rats, and several flies.

  But the Soviets were not so lucky this time. As the delegates assembled in New York, the first rocket to Mars failed, climbing just 120 kilometers before falling back to Earth and crashing in eastern Siberia. Then the second rocket failed: A cryogenic leak had frozen the kerosene fuel in the engine inlet. Khrushchev had been relying on another splendid performance from his ambitious young space program and was furious as he paced the halls of the U.N. Before the plenary meeting came to a close, he supposedly went so far as to pull off his shoe, enraged, and brandish it angrily at another country’s delegate.

  The Soviets tried again with a trio of missions in 1962. The first ruptured in orbit, fanning out debris that was detected by a U.S. radar installation in Alaska. It was nine days into the Cuban Missile Crisis, and the wreckage was momentarily feared by Air Defense Command to be the start of a Soviet nuclear attack. The third also exploded, the main hull of the booster reentering the atmosphere on Christmas Day, followed a month later by the payload. The second, however, traveled 100 million kilometers away from Earth and went on to make the first flyby of Mars—though it was a mute witness to the event, as its transmitter failed, the same thing that happened two years later.

  The Soviets kept their defeats to themselves and trumpeted their successes—which were numerous enough to show that they had a decided lead over the Americans. They had reached practically every milestone in the Space Race: the first artificial satellite, the first animal in space, the first man, the first woman. They’d intentionally crashed a spacecraft into the moon and taken the first pictures of its far side, and they were now poised to claim the first spacewalk.

  The United States, by contrast, had successfully completed only one planetary mission, Mariner 2 to Venus. Worse, the Venus mission, the “Mission of Seven Miracles,” had barely worked. It was a wonder that it had managed to collect any data at all, flying by the seat of its pants, “limping on one solar panel and heated to within an inch of its life.”

  And getting to Venus was easier than getting to Mars. To reach the Red Planet, the spacecraft’s systems had to stay alive for an extra hundred days, and the data had to be transmitted twice as far. Transistors were new and bulky, and the microchip had just been invented. The computing power of the whole spacecraft was no better than that of a pocket calculator, yet the spacecraft had to rely on a never-before-tested star tracker to point the way. For the first time in history, a NASA probe was drifting into the darkness, traveling away from everything bright in the night—the Earth, the moon, the sun. Just like Coleridge’s ancient mariner, it was poised to be “the first that ever burst/Into that silent sea.”

  Originally, there were to be two Mariner missions to Mars: identical-twin spacecraft, nicknamed the “flying windmills.” Mariners 3 and 4 were supposed to zoom by the planet just weeks apart. But the plan went awry when Mariner 3 was lost within minutes of launch. The rocket, an Atlas-Agena, had performed beautifully, but it soon became apparent that something was amiss. The data coming back from Johannesburg indicated that the spacecraft wasn’t on the expected trajectory. The nose fairing, which was designed to protect Mariner 3 from the crushing force of the launch, hadn’t properly detached from the probe. For nine hours, the operations team fought desperately to find some way to rip it off. They tried everything, including firing the spacecraft’s motor, but the batteries finally gave way, and Mariner 3 drifted into a derelict orbit around the sun.

  Mars and Earth align on the same side of the sun only once every twenty-six months, so the team had just a few weeks to engineer a solution before Mars moved out of range. The material for the nose fairing had been fabricated and tested under the dense atmospheric pressure of Earth, and they realized that its honeycombed fiberglass skin had started to pop like popcorn in the vacuum of space, expanding enough to wedge the nose fairing tight. The engineers worked around the clock, eventually recognizing that the honeycombed design could be salvaged by poking tiny holes in each cell to equalize the pressure. Just twenty-three days after Mariner 3 had failed, Mariner 4 was, improbably enough, ready to launch. It sat on Pad 37 the night before takeoff, shining under the brilliant spotlights. When morning came, it roared forth, lifting off Cape Kennedy on the wings of an Atlas booster. When the rocket released the spacecraft, the nose shield popped right off, just as it was designed to do.

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  AS MARINER 4 left Earth’s shadow, it began to roll through space. Its first task was to locate distant Canopus, the reference star its onboard sensor would use for navigation. The onboard sensor locked on to Alpha Cephei, far to the north, then moved southward to Regulus, then Zeta Puppis, then an unnamed cluster of three stars. It finally found Canopus, but soon it locked on to a stray light pattern. Then Regulus again. The sensor lost its way no less than forty times throughout its long cruise, as small dust particles and flecks of paint, shining fiercely in the sunlight, kept getting dislodged and falling into the sensor’s field of view. The spacecraft stumbled the entire way to Mars, but it survived the 523-million-kilometer journey, circling halfway around the sun. NASA was only seven years old, and this quarter ton of technology was already being heralded as America’s greatest achievement in space.

  Inside the JPL Space Flight Operations Facility, among the dark-slacked, short-sleeved men with narrow dark ties clipped to the fronts of their shirts, was Bob Leighton, the head of the Mariner 4 imaging team. That there was an imaging team at all was itself an unlikely development. The prevailing attitude at the time was that photographs were trivial. “Pictures, that’s not science. That’s just public information,” recalled a project manager for NASA’s unmanned Ranger missions to the moon.

  But Leighton had a deep passion for photography. He knew how to render an image, how to bear witness to a pattern of light. He knew what it meant to really see something. He’d grown up poor in California—raised by a single mother, who’d made her living as a maid in a Los Angeles hotel. Not long after Leighton graduated, a high school photography teacher found him a job at a photography lab for a Hollywood advertising firm. He could very well have ended up a professional photographer, had his penchant for neatness and efficiency not gotten the best of him. In 1939, he threw out what he thought was a stack of scrap paper, only to discover that it was a client’s underexposed blue-light negatives of an elegant steamship sailing under the Golden Gate Bridge. He got his walking papers and returned to L.A. City College. He transferred into the physics department at Caltech his junior year, then never left, joining the faculty in 1949.

  Leighton had spent the decade before Mariner 4 working at the Mount Wilson Observatory. On just a shoestring budget, he’d built an image-stabilization device, a “guider,” and taken photos of the planets. He was supposed to be observing stars and galaxies, charting redshifts, making fundamental discoveries about astrophysics—not watching the planets, which were considered too small, cold, and close to reveal much of anything about the nature of the universe. But he couldn’t resist catching glimpses now and again. When no one else was around, mostly on holidays like Thanksgiving and Christmas Eve, he’d sneak peeks through the 1.5-meter telescope.

  One of Leighton’s students had recently been hired by JPL. He told his colleagues about how his former mentor had been able to remove some of the atmospheric turbulence and make movies up at Mount Wilson, beautiful movies, for the first time in color, of a rotating Mars. When an amateurish TV exp
eriment was finally suggested for the mission, the student pleaded with his old professor: “Bob, as a duty to our community, you’ve got to make a proposal on the TV experiment to Mars. This other one is terrible.”

  Leighton acquiesced, and within a matter of months, he designed a gizmo with a slow-scan television camera capable of taking twenty-one photographs of Mars over the course of twenty-five minutes. The hope was to collect images of Elysium, then Trivium Charontis, then sweep across Zephyria and into Mare Cimmerium, catching a glimpse of the desert Electis before petering out to the south of Aonius Sinus. For each image, the camera’s shutter would click open for a fifth of a second. The pictures would be recorded on a ribbon of magnetic tape, then radioed back to Earth via Mariner 4’s high-gain antenna. In a sense, it would be the world’s first digital camera.

  For decades, the best telescopic observations, on the best of days, had only brought Mars a few times closer than the moon appears to the naked eye. The pictures from Leighton’s system on Mariner 4 would be incalculably better, resolving features as small as 3.2 kilometers across. They would give the world a firsthand view of Mars. Like Martin Luther insisting on a direct relationship with God, the imaging eliminated the need for an interpreter—or “scientific priest,” in the words of the youngest member of Leighton’s team. The pictures could be spread all over the world for everyone to see, in a language everyone could understand.

  But Leighton knew that photographing Mars was more than just an opportunity to share the mission’s findings directly with the public. It would be the culmination of a long quest to see an entity we’d never encountered, an entity that had puzzled us for centuries. What was Mars exactly?

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  AS INCONCEIVABLE AS it sounds, Mars wasn’t always understood to be a place. To be sure, the ancients knew there was something intriguing about Mars. The Mesopotamians noticed that it followed a strange loop in the night sky, drifting separately from the “fixed” stars. Everything in the immense night moved together, everything except five little wanderers. Of those, only one appeared as a blazing red lamp. It wasn’t only the planet’s distinctive color that made it perplexing but also its motion. Mars drifted eastward, night after night, in relation to the other stars, but for about ten weeks every couple of years, it suddenly turned and backpedaled against the zodiac, wandering west for sixty to eighty days before resuming its normal course. In effect, it traced out an elongated loop. Sometimes the size of the loop was smaller, sometimes larger. From this, Plato concluded that the planets had souls, for what could these retrograde acts be, he reasoned, if not expressions of free will?

  It wasn’t until Galileo looked through a spyglass from a columned terrace in Padua that Mars began its transformation from a glint of light into a world. Within a short stretch of weeks, it became clear to him not only where Mars was in relation to other celestial objects but also what it was. Galileo constructed his perspicillum, or telescope, with his own hands. He mounted it on a stand, and because of its tiny field of view, he had to be utterly still, barely breathing, hoping the falling evening temperatures wouldn’t cause the glass to mist over. But through its tiny aperture, he determined Mars to be a spherical body illuminated by the sun.

  As to whether this body was like the Earth, Galileo was not sure. He hedged in a letter he sent in 1612: “If we could believe with any probability that there were living beings and vegetables on the moon or any planet, different not only from terrestrial ones but remote from our wildest imaginings, I should for my part neither affirm it nor deny it, but should leave the decision to wiser men than I.”

  The quest to determine the nature of Mars by seeing it better would continue for centuries. When Galileo first looked through his rudimentary telescope, Mars appeared only the size of a poppy seed. But soon concave lenses gave way to convex ones, inverting the image—a minor inconvenience for a much larger field of view. Focal lengths began to grow, and new lenses reduced the optical distortions that Galileo had tried to mitigate with a cardboard washer. In 1659, the Dutch astronomer Christiaan Huygens stuck a telescope out the attic window of his father’s large house in The Hague and sketched the first map of Mars. Within a circle, he drew a v-shaped scribble of ink to denote a dark splotch on the planet’s surface. In the nights to come, he watched the shadowy blob disappear and reappear. It looked vaguely like an hourglass. It would later be called the Hourglass Sea, the first known surface feature on the planet. After mounting a tiny measuring device to the eyepiece of his rig, he estimated rather accurately that Mars was about 60 percent the size of Earth.

  Much to Huygens’s surprise, his observations also revealed that the length of the Martian day was roughly twenty-four hours, practically the same as Earth’s. These and other similarities between the two planets fueled speculation about Mars’s inhabitants. Huygens assumed the presence of intelligent beings, arguing that the planets could not be viewed as “nothing but vast Deserts, lifeless and inanimate Stocks and Stones,” for doing so would “sink [the planets] below the Earth in Beauty and Dignity—a thing that no reason will permit.” He went so far as to speculate about extraplanetary mathematics, envisioning tables of sines and logarithms, since “there’s no reason but the old one, of our being better than all the World, to hinder them from being as happy in their Discoveries, and as ingenious in their Inventions as we ourselves are.”

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  MEANWHILE, AT CAMBRIDGE University, Isaac Newton was developing the basic optics of a new telescope: the reflector. Lenses at the time could not bring red and blue light to the same focus, resulting in a haze of color surrounding bright objects. So instead of a lens, he designed a prototype that collected light by way of a curved metal mirror: six parts copper, two parts tin. It was a tiny instrument, sixteen centimeters long, yielding a magnification of only thirty-five times. Within a century, however, Newton’s design would have sweeping implications, enabling unprecedented enlargements of celestial objects. In 1773, William Herschel, a German-born musician living in Bath, England, began experimenting with the construction of mirrors in his spare time. In collaboration with his brilliant younger sister, Caroline, who went on to discover scores of comets and nebulae, he ended up building dozens of reflecting telescopes. From his south-facing garden, he was the first to detect the faint light of Uranus. He also trained his beautifully handcrafted instruments on Mars, revealing that the planet had white polar caps, “clouds and vapors floating in the atmosphere,” and seasonal cycles similar to those of the Earth. In 1784, he gave an address to the Royal Society that cast Mars as a kind of copy of the Earth, noting that its inhabitants “probably enjoy a situation in many respects similar to our own.” As the observations about the planet continued to roll in, they all fit with the idea of Mars as another Earth, a planet with its own oceans to sail and lands to walk, a place we could recognize, relate to, and imagine.

  The idea that Mars was like our planet only drove the quest to see it better. Newton’s reflector telescope was soon surpassed, as the speculum metal used for mirrors in large reflecting telescopes was quick to tarnish, and the polishing process often distorted the curve of the mirror. Instead, refracting telescopes, like Huygens’s, using two lenses instead of two mirrors, came back into vogue in the nineteenth century. These gradually grew and grew, with lenses so large that gravity began to cause the glass to collapse in on itself. Important discoveries were made, seasonal changes were tracked, moons were discovered. Telescopes, these magical instruments, transported us and let us see what we had never seen before. For hundreds of years, they were our only way to understand Mars.

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  NOT LONG AFTER I graduated from college, I convinced my father to come with me on a trip into thin desert air. He got on an airplane with me, something he’d only done a few times in his life, and we flew from Kentucky to Atlanta and then on to Tucson. We rented a car and drove deep
into Arizona’s Old West country, to a hill over a kilometer above the San Pedro River Valley. There was a little hotel, which closed several years ago, at the Vega-Bray Observatory.

  We checked in, then went to examine the telescopes. There was a forty-six-centimeter reflector beneath a roll-off roof, a couple of thirty-centimeter Meades, and a half-meter Maksutov-Cassegrain. We zeroed in on a twenty-centimeter Newtonian scope optimized for planetary viewing, which we moved to the observing deck just after dark. There was no tracking system or computer on it, just a sighting mechanism, which was all we needed. My father knew everything about the night sky.

  He had spent a good deal of my childhood in the backyard with sky maps from Astronomy magazine tucked beneath his elbow. As much as my father would have loved training for a career in geology or astronomy, he’d needed a job to make ends meet, and he’d found one working with the state health department, just like my grandfather had. I’d seen the night sky many times through his oversized binoculars, which invariably wobbled in my hands, even though he always tried to hold them steady for me.

  By this point in my life, I’d been to places like Lick Observatory and Mount Wilson Observatory. I’d spent my summers interning at NASA, and I’d visited the giant domes. I’d seen the data that state-of-the-art telescopes could collect flickering on computer screens. But there was something different about seeing the sky through a medium-range telescope at Vega-Bray.

  That night in the desert, I sensed for the first time what Galileo and other early astronomers must have felt, something that’s been lost in the age of computers. Planetary science used to be an amateur enterprise. Before the dawn of the Space Age, every single practitioner had a direct relationship with the night sky. They were awake when others slept, alone with their science and their thoughts, enveloped by the vast physical world. To point the barrel of a telescope at a tiny dot in the sky and then see it as a world, that dot, that very one right there! Of all the thousand pinpricks of lights, that one is different. That one’s threaded by rings. That one has tiny moons, suspended like marbles. That little alabaster hat is a polar cap. That one is a world.