Soon Horowitz’s new experiment was selected as one of four instruments to fly on the Viking mission—alongside a modified version of Gulliver, the Wolf Trap, and a final instrument nicknamed the “chicken soup,” run by Vance Oyama. This last one was based on the idea that the more food the Martian microbes got, the more respiration there would be to measure. Oyama’s instrument added lots of water and a wide variety of nutrients—the chicken soup—and then watched for changes in the composition of gases in the chamber as a result of metabolic activity. But by the time the instrument selections were made, the Dry Valleys results had convinced Horowitz that the chance of life on Mars was negligible—so low, in fact, that he even argued that it was pointless to sterilize the spacecraft. His instrument and the other three were exceedingly likely to fail.
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INCREASINGLY, THE ACADEMIC community was looking askance at the entire effort. EASTEX and WESTEX had drawn a number of scientific heavyweights, but they were mostly scientists who were far along in their careers, already decorated with awards and endowed chairs. Exobiology was a safe side game for Nobel Prize winners. But it was risky as hell to stake one’s career on it—something Sagan and Vishniac found out the hard way.
After landing an assistant professor position at Harvard in the early 1960s, Sagan had little reason to doubt his tenure prospects, even though the bar was high. He’d conducted peer-reviewed research for years, and not just in exobiology. His pioneering work on the makeup of the Venusian atmosphere—and the idea that its incredibly hot temperatures were due to the greenhouse effect—had been proved largely correct by the data returned from the Mariner 2 mission to Venus in 1962. He’d written scores of scientific articles and had received NASA funding for his work. But in his fifth year, just as Viking was beginning to be planned, he was told point-blank that tenure would not be forthcoming. Little more was communicated.
Frantic, he approached crosstown-rival MIT about the possibilities there, but after an initial warm response from the geology and geophysics department, their interest suddenly and inexplicably cooled. Sagan knew exobiology was precarious. Vishniac’s father-in-law was on the faculty at Harvard, and many of Sagan’s fellow astronomers shared the elder scientist’s skeptical views. As they collected their coffee and paced the hallways, they quipped that exobiology’s “speculations cannot be confirmed with observations or experiments and so it is not a science; it has no data. It only sounds like a science.” But Sagan had his supporters; his résumé was sterling and his funding secure, so what was happening?
Unbeknownst to Sagan, his star had dimmed because he had been abandoned by one of his oldest, most trusted mentors. His undergraduate thesis advisor from the University of Chicago, Harold Urey, had written a tenure letter to Harvard, and a similar one to MIT, denigrating Sagan’s work. He described “the sort of activity that Carl Sagan has been engaged in for years” as “very long, wordy, voluminous papers that have comparatively little value…many, many words, oftentimes quite useless.” He characterized Sagan as a kind of planetary dilettante who had “dashed all over the field of the planets—life, origin of life, atmospheres, all sorts of things.” Hearkening back to his experience as Sagan’s mentor at University of Chicago, he twisted the knife: “Personally I mistrust[ed] his work from the beginning. He is a smart fellow and he is interesting to talk to. Perhaps he will be a valuable professor at your institution. But for years I have been disturbed by this sort of thing…”
Sagan had no idea Urey considered him a dilettante, and he wouldn’t find out for years—not until long after he finally secured a post at Cornell. The news would come out of the blue in the form of an apology that arrived in the post. “I have been completely wrong,” Urey wrote on September 17, 1973, as he asked for Sagan’s forgiveness and friendship. “I admire the things you do and the vigor with which you attack them.” Sagan responded magnanimously, but what cold comfort it must have given Sagan to know that his trusted mentor regretted having secretly undermined his career.
With the benefit of hindsight, it seems that Urey was cruelly slow to see the value of Sagan’s scientific work. Even if some of his papers meandered, Sagan was a tireless worker whose research made important contributions. Urey should have been the first, not the last, to realize this: After all, when Sagan received Urey’s biting criticisms of his undergraduate draft thesis, he carefully redid the entire thing. As a PhD student, years before Mariner 9, Sagan had bravely taken on his own PhD advisor about the wave of darkening, not by discounting data but by embracing it: He argued correctly that the known evidence better supported a lifting and settling of dust. And Sagan’s PhD advisor was no ordinary scientist but Gerard Kuiper, who at the time was the most prominent planetary scientist in the world. That Urey would not have understood the depth of his commitment to science, or his talent, must have been crushing to Sagan, even all those years later. Such were the perils of championing a new scientific discipline and of doing it so publicly.
A bright spot was that Sagan’s position at Cornell placed him not far from Vishniac, who was at the University of Rochester. They would see each other often, not only in New York State but also, as meetings took them to the far corners of the world, in places like Tokyo, Barcelona, Leningrad, and Konstanz. It was a friendship between kindred spirits. And then of course there was the excitement of Viking’s life detection efforts. Although they recognized the scientific value of a negative result—and appreciated that it would place at humanity’s disposal a planetary surface that hadn’t been “turned topsy-turvy” by living organisms, a kind of control group—they both dearly hoped that Viking would be successful, that life would at least be hinted at if not definitively discovered.
The mission’s engineering task, however, was enormous. By the early 1970s, Viking was millions of dollars over budget, with time running out. The biology package, which had been billed as the “greatest experiment in the history of science,” was the most behind. The automation was extremely challenging: There were forty thousand parts, half of them transistors that had to be assembled, plus tiny ovens, nutrient-containing ampules that had to be broken on command, bottled radioactive gases, Geiger counters, and a xenon lamp to mimic the light of the sun. The instruments and the receiving end of a sample delivery system had to be shoehorned into a sixteen-kilogram box, measuring about the size of a milk crate. Somewhere had to fit reservoirs for helium, krypton, and carbon dioxide, fifteen meters of stainless-steel tubing, heaters, coolers, test cells, dump cells, a thermostat, and a carousel.
Bad news came quickly for Vishniac. He had originally been appointed to lead the biology team, but unable to keep up with the draconian deadlines—Vishniac tended to “let everyone have his say”—he was replaced by someone with a considerably more authoritative air. Then, with little warning, Viking dropped the Wolf Trap altogether. The original estimated cost of $13.7 million for building the life detection experiments package had ballooned to more than $59 million. It became clear that the biology payload would have to be simplified and that at least one instrument had to be cut. The one the team chose was the light-scattering experiment, Vishniac’s brainchild. Cloudiness might result from the dispersion of fine soil particles, not just microbial proliferation, and whereas all of the other instruments could detect resting metabolisms, the Wolf Trap required conditions of growth. It was too complicated and already running behind schedule. In the background was Horowitz—persuasively arguing that the Wolf Trap, like the chicken soup, would probably drown any Martian life.
When he found out the news, Vishniac was devastated. For more than a decade, his scientific career had been focused on life detection on Mars and the Viking mission, on what many of his peers considered a boondoggle. And now he would not have the chance to prove his critics wrong. He remained on the Viking team, but he no longer received NASA money to support his research, and he struggled to secure any funds from the National Institutes of Health and the Na
tional Science Foundation. “The consequences of my change in status in the Viking team have been far-reaching, as you know, not to say disastrous,” he told the mission’s project scientist. “It is essential that I recapture some sort of standing in the academic world.”
With time on his hands in 1972, and then again in 1973, Vishniac decided to venture down to Antarctica himself. He was nothing if not determined. He had a weak arm from a birth injury, with limited mobility, but nevertheless he’d taken up winter sports as a teenager. He had a stutter, but he’d become a public lecturer and professor. He’d even failed the glucose tolerance test as part of a Navy physical to travel to Antarctica, but “knowing something about the chemistry of the test,” he’d devised a way to pass it on his second try. He was intent on showing that Horowitz was wrong, that life could exist in extremely arid conditions, and that the Viking mission wasn’t, in fact, completely hopeless.
At the beginning of his expedition in 1973, Vishniac gingerly tucked glass slides coated with nutrients into folds of soil high in the Asgard Range, named, appropriately enough, after the homeland of the Viking gods. The experiment was like Sagan’s Mars jars, but it was conducted in nature, in one of the most Mars-like places on Earth.
A month later, two weeks before Christmas, Vishniac began collecting his slides. It was nearing midnight as he made the rounds, although the sun never sets in Antarctica in December. His colleague Zeddie Bowen had stayed at their camp to await a supply plane. The men often ventured out alone: “Always in good weather and with an expected route and timetable. The route was not dangerous.” But twelve hours later, when Vishniac hadn’t returned, Bowen went looking for him. At worst, he envisioned a broken ankle. “What I really expected was to find him distracted by some fascinating new discovery or observation.” Instead, he found Vishniac’s lifeless body at the base of a cliff, beneath a hundred-and-fifty-meter ice slope. He’d taken a different route, “following his curiosity,” then a wrong step. His body was recovered by the crew of a Navy helicopter, then transferred home to Rochester. Vishniac left behind his wife, Helen, their two teenage boys, and a devastated Viking biology team, who respected Vishniac deeply, even though they’d been forced to jettison his instrument. They gathered at the funeral, held in the cold New York winter.
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WITH COST OVERRUNS and engineering challenges, and the terrible tragedy of Vishniac’s death, it was a near miracle that the Viking biology package was delivered in time for launch. The absence of the Wolf Trap was ever so palpable, and the anguished team struggled to complete their work. The time pressures on Viking were such that, had the Wolf Trap remained part of the mission, Vishniac probably wouldn’t have been in Antarctica; he would have been there with them, finishing the project.
But finally, two biology payloads, one for each lander, were complete. On March 7, 1975, NASA’s Langley Research Center wrote to the Viking project office and contractors announcing that the streamlined Viking biology suite was at long last in its shipping box, ready for delivery.
By the time the instruments arrived in Florida, there were nearly daily thunderstorms at the cape, and time was running out. Even though Horowitz had argued that fears about terrestrial microorganisms multiplying and contaminating the planet were silly, the landers were nevertheless sealed beneath their ablation shields and inched like giant mushrooms into a 112-degree-Celsius oven to be sterilized. There they steeped beneath searing clouds of nitrogen gas for forty hours. Assembly and testing continued, right up until August 20, 1975, when Viking 1, the first of the identical spacecraft, soared into space on a Titan IIIE rocket. Viking 2 followed just three weeks later.
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WITH GREAT FANFARE, the first lander was scheduled to touch down on the surface of Mars on America’s bicentennial. The nominal landing site was near a deep and wide swath of terrain at the mouth of Valles Marineris, a floodplain where water was thought to have flowed out of the giant canyon. There in Chryse Planitia, the “plains of gold,” was the confluence of several ancient river channels. The site was also far below the mean surface of the planet, hinting at the possibility that snow, ice, and perhaps even traces of transient liquid water—less likely to evaporate under the greater atmospheric pressure—might be present.
On the other side of the planet was the nominal location for the landing site of Viking 2. Cydonia, right at the lower edge of the north polar hood, was near the ice. As a result, the atmospheric humidity was anticipated to be high, and it was hypothesized that microbes might even drink water from passing clouds.
Both sites had been chosen for their smoothness in the Mariner 9 pictures, with landing zones carefully fitted between craters and canyons, but as the first orbital color images began trickling back from Mars in June of 1976, the terrain was nothing like the team expected. The orbiters had been designed to photograph the planet to help assess the landing sites before the landers detached, but rocky knobs, steep slopes, and hidden small craters suddenly spattered into focus. The team realized that even after the giant dust storm of 1971 had subsided, a haze must have persisted in the air, filtering the Mariner 9 images, dampening the contrast, making the terrain appear softer and more muted than it really was.
“It may be that we don’t understand Mars at all,” wrote the mission’s project manager, sending jitters throughout JPL. “But we shall find a place to land, I think…” It was generally agreed that crashing into Mars on the bicentennial would be a bad idea, so the July 4 date was scrubbed, and the team began scrambling to find an alternative. Again, time was short. The landings had been scheduled more or less on top of each other, and the communications network would soon become strained.
So for the next two weeks, the orbiter went tacking across the surface, searching for safe ground. The landing site had to be a low-lying area so that the lander’s huge parachute—sixteen meters wide, as large as the team could make it—would be able to catch enough atmosphere to slow down the speeding capsule. The site couldn’t be out of communication range of the orbiters or too cold for the instruments to operate, which eliminated large swaths of the high latitudes. It had to be fairly flat, or else the lander might land at an angle, leaving the mechanical arms “waving helplessly” above the surface. But hard lava had to be avoided too, as there would be no soil for the arm to collect and analyze.
Finally, a site was chosen for the first lander. It was also in Chryse, though not near the confluence of the ancient river channels. On July 20, Viking 1 split in two. Like an artillery shell, the descent capsule barreled toward the surface of Mars on a ballistic trajectory, while the orbiter continued to circle. At nine hundred kilometers an hour, about six kilometers above the surface, the parachute deployed. A kilometer and a half above the surface, after the aeroshell had been jettisoned and the legs had begun to unfold, the parachute was cut and the retrorockets were activated. Within seconds, the beetle-shaped lander came to rest softly on the surface. Cheers erupted throughout JPL. The sheer fact that a spacecraft could land on another planet was itself extraordinary, considering it had largely been accomplished with just vellum and notepads.
The images of the landing site from the Viking orbiter were a vast improvement over the Mariner 9 images, which from fifteen hundred kilometers up hadn’t been able to spot anything smaller than the Rose Bowl. Even the Viking orbiters, with their better coverage, could only resolve features bigger than about a hundred meters across. Because no one knew what the surface of Mars would actually be like, the first image was of the lander’s foot, simply to make sure the surface was solid.
The next image was of rocky terrain beneath a bright blue sky. Upon seeing it, one scientist began wandering down the halls of JPL, cheerily singing, “Blue skies, do dah dah dah…” Many on the team, Sagan included, had predicted the sky would be black overhead because of the very thin atmosphere, then a lighter blue-black near the horizon, where
there was more atmosphere to look through. Strange that the sky was so bright.
The image-processing laboratory, which corrected for things like the sun angle, uneven shading, and curvature distortions, slowly began to realize that the first image had registered the appearance of the atmosphere incorrectly. The color on the lander’s facsimile cameras had to be calibrated, numerically re-creating the hues because the color diodes were also sensitive to infrared light. The engineers soon discovered that the sky on Mars wasn’t a luminous bright blue, but, weirdly, it wasn’t a dark blue-black either. It was full of light and orange, the color of butterscotch—light reflecting off billions of tiny dust particles in the air.
The image was quickly corrected, and as additional images came down, Sagan eagerly studied them, buoyed by optimism, acutely aware that the cameras were the only instruments, in principle, that could prove the existence of life on Mars in a single observation. He had lamented that the search for landing sites would plop the Viking probes down on the most boring parts on Mars: “We knew we had chosen dull places. But we could hope.” In the end, the most interesting feature to photograph was “Big Joe,” a boulder a few meters out of reach. In a press conference on the mission’s eleventh day, Sagan joked with the gathered reporters that no rocks had gotten up and moved away, at least not yet.
Despite the stillness of the terrain, the biology experiments suggested that something very exciting was happening in Chryse Planitia. Initial samples had been scooped up with a telescoping arm from a bare patch of soil in front of a rock named “Shadow.” After being delivered to little buckets “like hoppers on an electric train,” they slowly rode inside the lander to be analyzed by the three life detection instruments as well as two others assessing the sample’s chemistry and mineralogy. The team was prepared to wait days or weeks for the incubations to yield results. Yet, miraculously, Oyama’s chicken soup experiment kicked up gases in just a couple of hours, potentially indicating a type of wildly fast metabolism. A spew of radioactively labeled carbon dioxide also was detected, by the modified Gulliver. The team was ecstatic. “We were so excited, we sent out and got champagne, cigars,” the instrument’s lead recalled. Then he and his associates solemnly sat down to sign and certify the data printouts, aware of the magnitude of what of they were doing. In his mind, the instruments had satisfied the mission requirements for the detection of life.
The Sirens of Mars Page 8