The Sirens of Mars

by Sarah Stewart Johnson

  After leaving El Capitan, the rover had stopped at a sinuous crack named Anatolia, then a small impact crater named Fram. The terrain had become sandier on the route to Endurance. Each day the engineers had to make hazard maps for the rover, and the rover could only go that far.

  On Sol 94, a scientist named Tim Parker called out from the far side of the room, “First Navcam frame is down….Anybody want a look?” We gathered around his computer, and as he opened the file, there was a collective audible gasp. The rover had climbed out of its landing crater many sols ago, traversed farther across Mars than any vehicle before it, and was now lurching over the chasm of Endurance. Its two front wheels were beyond the lip of the crater, which had been three meters closer than the engineers realized. Opportunity had just driven and driven until a hazard warning kicked off the power.

  He threw the image up on the huge screen in the front of the room, and we slowly fell back into our chairs. Ours were the first human eyes to peer into that mysterious abyss, and it was one of the most breathtaking things I’d ever seen. As I stared into the center of the crater, I felt like Alice in Wonderland falling through a rabbit hole. “What is this world?” I thought, there on the verge of Endurance, my eyes wide. “What is this piercingly wild place?” The giant cavity was laced with hummocks of sand. The most ethereal gossamer dunes filled the void at its center, unlike any dunes I’d ever seen. They looked like egg whites whipped into soft pinnacles. And enveloping the edges, there was undulating outcrop, cut with gorgeous striations, deeper than I was tall. I was supposed to fly back to Boston in a couple of days, but this I couldn’t leave.

  I decided then and there that I’d do whatever it took to convince the team to let me stay. I had never wanted anything so badly. I lingered at JPL that night, even after the sol completed, trying to figure out how to make it happen. I could take incompletes in my classes, I realized; I could sleep on my friend’s couch, on the floor if I had to. I could help manage the flash data storage, completing the daily checks. I could train as a PUL, a Payload Uplink Lead, uplinking code to the microscopic imager. I implored my mentors, and when they agreed to take the request to Steve to consider, I nearly leapt from my chair.

  At the time, I wasn’t sure if Steve, as the leader of the entire mission, even knew my name, and I had no idea how he would respond. But as it turned out, Steve’s own path into planetary science had been rather serendipitous too. It started with a high school friend falling from a pair of ice axes. Steve was a teenager learning to ice-climb, trying to shore up his mountaineering skills to be admitted to the Juneau Icefield Research Program, a summer program funded by the National Science Foundation. He’d accompanied his friend out to western Massachusetts, and when his friend’s wrist cracked apart, Steve had to splint it and carry him to safety. His friend’s mom wrote him a recommendation for the program, which clinched his admission.

  So Steve spent the summer of 1974 skiing, a pair of red gaiters flashing across the ice. It was there that he fell in love with vast and distant places. He initially thought he might go into marine geology and spend his life at sea. Perhaps he could map the bottom of the ocean, a colossal frontier that had never been surveyed. Then one afternoon as an undergraduate, he saw a new map posted in the geology department. It showed mid-ocean ridges zippering across the globe, all in intricate detail. “Well, crap,” Steve thought, “the ocean’s been done.” The next semester, on a lark, he signed up for a graduate course on the Viking mission results. The final assignment was to analyze the original surface images. He swung by the “Mars Room” late one afternoon, expecting to pick a topic in fifteen to twenty minutes. Four hours later, he emerged knowing what he wanted to do for the rest of his life.

  There weren’t many places in the United States to get a PhD in planetary science, to study geology but not as it occurred on Earth. Cornell, where he was already an undergraduate, was one. He applied “for completeness,” expecting to make his way to a new university, with no inkling that he’d spend most of his life in Ithaca. A few weeks later, he received a note from Carl Sagan, who’d seen his application, suggesting the possibility of working with him on the Voyager mission. Sagan was a Cornell professor, but he spent most of his time in California. They hadn’t ever met, but what could be more exciting than the “Grand Tour,” two tiny probes that would travel for the first time to all the planets of the outer solar system? Steve accepted Cornell’s admission offer. Even though Sagan barely set foot in Ithaca while Steve was in graduate school, they would see each other at JPL often. At the time, Steve had no idea how much planning went into space missions—the engineering, the rocketry, all the preparations, all the cost. He was a student, and when he showed up and was provided with the data on a platter, he didn’t have to ask those kinds of questions. He felt like he’d been given the keys to the universe.

  And that’s how I felt when Grotz told me I could stay, when Ray offered to arrange for a badge, when Maria assured me she would clear any bureaucratic hurdles with my graduate program. “This is how it begins,” I thought, “with a bit of luck!” I didn’t appreciate it at the time, but Steve had spent years learning every circuit on the rovers, every pyro, every destination of every bit of wire. He’d met every engineer and considered every failure path. I’d done nothing to help get those rovers to Mars, but because of his hard work, I’d been given the chance to zoom to the very epicenter of modern planetary science, where everything was shot through with light. Instead of packing for my flight home, I called the airline. I couldn’t stop smiling when the woman on the phone confirmed, “Return indefinite.”

  * * *

  —

  THERE WAS NO shortage of fascinating work. As we inched below the western ridge of Endurance Crater, we realized the rocks were stippled with blueberries all the way down. And as we looked at orbital images, it seemed that the same geologic formation probably extended tens if not hundreds of meters down and kilometers across. Not a little water but a lot of water would have been required to make them.

  On the opposite side of the planet, Spirit was heading for the Columbia Hills, which rose like islands above a sea of incessant basalt. We reasoned there might be sedimentary rocks there, once deposited in water—rocks that hadn’t been buried by lava. The rover made great time, covering real distance. There had never been a mission like it, and every day there was a new vista. When Spirit reached the base of the West Spur of Husband Hill, over three kilometers away from its landing site, it uncovered traces of hematite, along with chemical enrichments from flowing water. And high above, tens of meters up the hill, there were even signs of layering.

  I worked mainly on helping to document the physical and chemical changes that had occurred as the playa lakes receded, as sediment had turned to rock, tracking things like the size and distribution of the blueberries. A couple of months after I arrived, at the beginning of the summer, Grotz returned to his fieldwork in Namibia. At that point, I joined one of his graduate students in the cavernous house he’d been staying in as a Caltech visiting professor. I had never lived in such a large, bare space. It felt like the house had been occupied, then emptied, just like the tabular crystal molds in the rocks I’d begun studying. They were called “vugs.” The tiny cavities—another diagenetic feature—were once filled with minerals like gypsum, which later dissolved away, leaving an angular, empty sliver behind. We knew that Meridiani was once wet, but those tiny vugs and blueberries were crucial for understanding the sequence and timing of water saturation; they were how we would understand if the waters had receded and returned and how long the wet conditions may have lasted.

  We began to find little clues, like a hematite blueberry forming in the cavity of a vug, which suggested that the rock in front of us, all those billions of years ago, had already been marked by a tiny absence—that the blueberries must have formed after both the creation and dissolution of the crystals. Soon there was enough evidence to conclude that th
e blueberries were one of the last features to form and that they’d formed under distinct environmental conditions. The story was coming together: Meridiani was a place where the water table had risen repeatedly in the ancient past, where waters had drenched the surface again and again.

  I’d brought next to nothing with me to California, and I’d acquired next to nothing since my arrival except for a badge and security token, a couple of books I’d found at a used-book store, and a rental car I would drive out onto the expressway to get to JPL. I’d exit and follow Oak Grove Drive as it curled north into the arroyo. Sometimes in the early-morning light, the roads felt desolate. There were no joggers running at the Rose Bowl, no students mingling on the balconies of La Cañada High School, no equestrians jumping at the Flintridge Riding Club. Even though the mission had shifted over to a modified version of Mars time, condensing the planning cycle in order to block out the hours in the middle of the night, it still felt as if the outside world had vanished. As I entered the gates of JPL, I felt like Nikos Kazantzakis, the giant of Greek literature, arriving at the wild and holy monasteries of Mount Athos. I walked beneath the olive and oak trees, then into the dark and hallowed halls. I took my place among my colleagues, at a computer with a terminal window open. Each screen filled with lines of code—commands that would beam from the mission team all the way to Mars, commands that would rebuild data files and assemble images faster than any human mind and, in so doing, illuminate the truths of a distant desert world. The scripts seemed incandescent, rasters of white letters and numbers gleaming from the black background. All the zeros were hemisected, like lines of gilded text. It felt holy to be in those rooms, committed more fully to the mission than I’d ever been committed to anything. Time had been obliterated. What remained was only the larger thing, in prismatic focus.

  * * *

  —

  IT CAUGHT ME off guard one day to be invited to see the Dodgers play. Steve was opening a game, and my name, along with a couple of others, had been pulled from a hat to join him. As I walked into the stadium, I was given a blue sticker in the shape of a baseball, with big letters spelling out the words “pregame guest.” I affixed mine to my jacket and followed Steve to the field. We’d brought along a handheld model of the rover, and I showed it to some of the players as the stadium seats began to fill.

  Just before the national anthem, one of the officials gestured that it was time for us to make our way to the pitcher’s mound. The grass was short and green and seemed to spring beneath my feet. My head arced slowly as I paced across the field, trying to take it all in. There were flags flying and, in the distance, palm trees. I tripped ever so slightly where the grass ended and the dirt began, then righted myself next to the pitcher’s mound, smack in the center of the enormous stadium.

  As I stood there, the announcer described the mission over the loudspeaker, booming stats about its success. An artist’s animation of the rover landing played across the JumboTron, just above an ad for the restaurant chain Carl’s Jr. As the stadium began to roar with applause, everything seemed to slow down. I felt the heat of the brown dust I’d kicked over my sandal, its warm grit gently falling between my toes. I realized I was supposed to be waving, but I was standing there motionless, unable to take my eyes off the teeming crowd. Here we were, a species. Thousands of human lives, thousands of tiny bodies in rows up to the sky.

  I drove to JPL later that night, swiped my badge in the turnstile, and roamed the campus until I found myself in Building 264, sitting alone in one of the high-back blue chairs. My mind kept wandering to the little tribe of scientists on the mound, standing there in the sunny stadium but mentally still far, far away. I realized that as I had become more and more absorbed in the mission, the fabric of connection that comprised my life in Boston had started to fade away. I no longer did ordinary things, like going to the bank or shopping for socks. I talked to my friends and family less and less. Staring up at those fans, though, I was suddenly, jarringly back in the middle of the world I had left behind, a human world. I wondered if Lowell had felt the same way, stepping away from his telescope, returning from the thirsty Arizona desert to Sevenels. Or Dollfus, thudding down from the sky into a cow pasture.

  In the grandest sense, we’d made it to Mars. If space were a giant sea, we’d found the next atoll. We’d fluttered out into a darkness of scattered islands, and we’d made landfall. We were now exploring like a restless finch, hopping among the rocks.

  We could even see our tracks from orbit—ever so faintly. They’d been pressed into the frigid soils, right up to the edge and down the side of Endurance. I thought about Ernest Shackleton’s ship, for which the crater had been named. It had been caught in the ice, crushed in the cold. As I looked around at the room, I saw the signs detailing prevention strategies for ANTICIPATIVE FATIGUE. Eat smaller meals. Drink lots of water. Try to exercise but never before bed. I saw the empty chairs, the motionless piles of papers.

  There was something I’d put on a shelf in my mind since the early days of the mission. It had all been so exhilarating at first—for years, NASA’s Mars strategy had been “follow the water,” and we’d found it, thousands of swimming pools’ worth of water. Water that had inundated the surface, water that had collected in playa lakes, reflecting the sky.

  But I couldn’t stop thinking about the jarosite that Opportunity had found in El Capitan. All the jarosite we knew of, in all the amber-yellow cracks and crevices where it was found on our planet, was formed in acidic water. And not just acidic water but highly acidic water. The U.S. Postal Service refuses to let scientists ship samples of it through the mail—it’s that corrosive.

  In places likes the ephemeral playa lakes of the Yilgarn Craton in western Australia, microbes can survive in pHs less than 2, right alongside jarosite. But it’s unlikely that life on Earth sprang from waters this acidic. Tiny organisms, even eukaryotes, can now tolerate the conditions, but they’ve adapted to do so, utilizing a sophisticated evolutionary machinery. Minerals like jarosite essentially form in sulfuric acid. Could we really expect life to form in these conditions?

  The team had also been doing work on salinity at Meridiani, and I knew a paper was under way for Science, one that concluded that salt levels may also have been much too high for even the hardiest microbes. It was the same reason the soy sauce in the JPL cafeteria never spoiled. Soy sauce contains lots of water, yet not enough unbound water for microbes to grow.

  How quickly chemistry could change things. We’d found water on Mars—the primary goal of the mission—and in the collective excitement, I was slow to realize that not all water gives life. The water on Mars might have been deadly.

  * * *

  —

  NEWS OF WORLD events had mostly come and gone during those secluded months at JPL. I was aware of happenings outside the mission—the CIA admitting there were no weapons of mass destruction in Iraq, the ongoing saga at Abu Ghraib—but if anything, these events just made Mars feel like a place where thoughts stayed safely within the realm of geologic time.

  Then one evening at mission control, I heard some of the team members talking about the Olympics. Ten thousand athletes were gathering in Athens for the 2004 games, back in the country where it had all begun. As a kind of commemoration, one of the team members suggested that we use Spirit’s Rock Abrasion Tool to carve the Olympics symbol into Martian rock. We’d already been using it to etch out patterns, incising five-centimeter circles into the Martian rock to peer beneath the dust and rock rind, often in clusters to accommodate the large field of view of some of the instruments. We’d left them strewn about the surface. We called the clusters “daisies,” as they looked like flowers: one central circle, flanked by a circle of circles.

  Sometimes the daisies were dark against the bright dust. Other times they were lighter than the rock. They were instrumental, of course, necessary to enable our measurements. But they were also reminiscent, however
inadvertently, of the impossibly fecund world the rovers had left behind. So one day in August, we decided to pause our normal brushing protocol at five circles on a rock named Clovis, three in a row, then two below, each interlaced. The rover’s camera captured an image of the rings, the first human symbol drawn onto the face of another planet.

  It reminded me of something I’d read about an Austrian astronomer proposing in the early 1800s that giant trenches be dug in the sands of the Sahara. They were to be in the shape of mathematical symbols, filled with kerosene and set alight in the desert’s darkness with the hope that the blaze might be visible from Mars. And of the German, not long before, who reportedly suggested sowing wheat into a giant right triangle in the Siberian tundra, bordered on each side by a square of pine forest, thereby invoking the Pythagorean theorem from space, which, of course, “any fool would understand.” And the Frenchman, not long after, and his network of seven mirrors that, if arranged properly across Europe, might beam up the shape of the Big Dipper.

  How tender it would have been: fires in the night, a field of pine, a glint of light. How tender and how futile. And now we too had been part of this, except it was Mars we marked, inscribing our ephemerality into terra firma, into one of the driest, oldest rocks onto which anything had ever been inscribed.

  In a way, the rings were a beautiful gesture. They felt as spare and evocative as the petroglyphs in Damaraland, pressed into the ochre walls of Twyfelfontein: an antelope on the plains, a shot bow. And in the Libyan Desert, the Cave of Swimmers in Gilf Kebir: bodies arced and gliding through an ancient lake, now vanished and buried beneath the sands of the Sahara.

  At the same time, what if it was pointless—the daisies, the rings, the fact that athletes in Athens were flinging sticks, running fast, and diving into the cool water that surrounds our planet? Would any of it matter against the backdrop of an empty cosmos?