The Mission

by David W. Brown

  Nothing for NASA was ever free . . . except for gravity assists. Ordinarily, the agency could compensate for the meager speeds of heavy spacecraft by taking indirect flight paths and using planets encountered along the way to yank and shove the robotic pilgrim outward, inward, or onward.225 The laws of physics being immutable, and the salient numbers known, NASA’s orbital dynamicists could do this all day, running the numbers to sling spacecraft precisely, one planet to the next: free propulsion from Isaac Newton.226 It was incomparably the best bargain in space exploration.

  But then television tabloid journalism got involved, and everything became complicated.

  In 1997, while waiting at Cape Canaveral for liftoff, the Cassini mission was beset suddenly by political protest. Cassini carried three radioisotope thermoelectric generators, which were powered by the decay of plutonium 238. The plutonium wasn’t of the Back to the Future variety—a disquieting drop of Scary Substance Indeed into a homemade flux capacitor—but rather was stored in a ceramic form, wrapped in iridium, and caked in graphite. It could not corrode, or be obliterated by heat, or vaporize, or disintegrate as an aerosol, or dissolve in water. It was made to withstand not only the explosion of the rocket carrying it, but even a catastrophic reentry into Earth’s atmosphere. Because it couldn’t vaporize, in a disaster situation, no one would inadvertently breathe it in and develop superpowers or extra appendages. In fact, it was designed so that you could even eat the stuff.227 The human body could not absorb it.

  But ten days before three and a half million pounds of rocket thrust put inches between Cassini and Earth, a much smaller number—sixty, as in 60 Minutes—nearly nailed NASA to the ground. The CBS TV newsmagazine aired a feature on the soon-set-for-Saturn spacecraft, Steve Kroft starring in the segment. The correspondent’s opening line: “On October thirteenth, a Titan IV rocket is scheduled to lift off from Cape Canaveral carrying seventy-two pounds of deadly plutonium; enough plutonium, in theory anyway, to administer a fatal dose to every man, woman and child on the face of the Earth several times over.”228

  And it got only worse from there. Cassini was an afterthought in the story, and interviews from experts were interspersed with comments from . . . nonexperts, to be kind, but very well-spoken nonexperts, whose contributions—the generous ones!—included lines such as: “What gives anybody, including the federal government, the right to risk the population’s death or—or injury just for space exploration?”

  The segment featured a plutonium expert from the Department of Energy stating flatly that even if the rocket, spacecraft, and graphite-sealed, iridium-wrapped, ceramic plutonium blew up on the launch pad, it was literally impossible for the debris to do what protesters said it would. But just to be balanced, Kroft’s menagerie of doomsayers described in lurid detail what plutonium—not in the form used by NASA, which you could safely sprinkle on your breakfast cereal, because, again, you could eat it—could do to the human body. Among the highlights: “it can produce pulmonary cancer” and “you could have numbers like one hundred thousand or more people who develop lung cancer” and “if there is such an explosion, you can kiss Florida good-bye.”

  Kroft even found a former NASA employee (“He’s neither a scientist nor an engineer,” admitted Kroft, “but . . .”) to lament publicly his role in endangering lives for such frivolities as space exploration. “I feel guilty, quite frankly,” bewailed the penitent insider.

  To seal the deal, Kroft intercut the story with snippets of an interview with Wes Huntress, head of NASA’s planetary program, who had presided over the successful landing of Mars Pathfinder only months earlier.

  “This is from your own environmental impact statement,” said Kroft to Huntress—the tone of the host solid but affable, his countenance hard but eyes somehow benevolent. “I want to read you a couple of things from it.”

  Huntress was a pioneer in the study of interstellar clouds and one of the world’s foremost experts in planetary exploration, but he was not exactly tabloid-TV material, and after the cavalcade of activists arguing compellingly and without interruption, he seemed less than confident in his responses.

  Quoted Kroft: “If there’s an accident it talks about, quote, ‘removing and disposing of all vegetation in contaminated areas, demolishing some or all structures and relocating the affected population permanently.’”

  “If there should be any such accident,” said Huntress, accurately but unhelpfully.

  Replied Kroft, “I mean, that sounds fairly drastic . . .” and Kroft waited patiently for Huntress, in possession of rope necessary to hang himself, to fill the silence, which 60 Minutes interview subjects always did, and he did, and did.

  “Well, the—what they’re probably talking about mostly is—is the damage on site, near the—near—near the launch pad because there’s clearly, when one of these things goes, a lot of damage near the launch pad.”

  And after Huntress tap-danced and staggered—this guy didn’t even know what his own official Armageddon report said!—and at last swung gracefully from the gallows, well-honed doomsayers followed up, explaining precisely how Life as We Know It was drawing to a close, and kiss your babies tonight because our foolhardy quest to conquer the cosmos—Saturn! This pointless mission to a gas giant, whatever that meant—will leave mutated survivors fighting for the last canned goods on ransacked store shelves.

  Worse yet, Cassini would take a second swing at the peaceful people of planet Earth! If it didn’t blow up on launch, it was set to follow a VVEJGA trajectory to boost its way toward Saturn: that is, two swings by Venus (V, V), and then it would play chicken with the Earth, and if something went wrong . . . (but if all went well, from Earth [E] to Jupiter [J] for a gravity assist [GA]).

  The Clinton administration really did not have time for this but dutifully absorbed the panicked letters and optics of protesters grasping concertina-topped chain-link fences on Cape Canaveral’s perimeter, while on the inside, police lined up in body armor and carrying riot shields stared silently, just waiting to—what? Open fire? Brandish batons?229

  Nevertheless, NASA went forward with its reckless rocket launch likely to leave only cockroaches crawling the Earth (or whatever some future species would call this planet), and things were fine, as they had been for previous launches dozens of times over. But the message from headquarters to those filing future space missions: if you must launch radioactive material, do not plan trajectories taking the spacecraft back to Earth for a gravity assist. Nobody needs the headache.230

  Which meant, for Karla and company, years-long discussions on potential trade-offs for the Europa Orbiter mission, as it came to be called. They analyzed other trajectories, other launch vehicles—anything to get more mass for a suitable science return. What hardware do you make “rad-hard”—impervious to radiation (but expensive)—versus simply wrap in “dumb mass” (i.e., big blocks of cheap protective shielding)? What was the absolute smallest science payload possible? Ultimately, they found a relatively happy medium: a spacecraft that could launch direct and achieve the minimum science required to make a Europa expedition worthwhile, and NASA loved it, and then the cost doubled, and in 1999 Ed Weiler shot it dead. Just like that.

  WHEN PROJECT PROMETHEUS came along, Karla was already at work on a conventional Europa mission, building from the previous Europa Orbiter effort. She had, by now, more engineering experience on that moon than most, having led or been part of four separate studies. When she learned what the Prometheus people planned to propose for Europa, she saw problems. She told John Casani point-blank that his engineers were underestimating the amount of mass necessary to pull off this sort of mission. The shielding, the instrumentation: Europa wasn’t the place you parachuted into with only a bowie knife and moxie—you went there, you packed for war. She told him this again and again until finally he pulled her aside and said gently but firmly to quit complaining about it, and either come over and help him on JIMO or leave him alone.

  It was not a difficult choice. If ther
e was something to learn about doing big things in space, John Casani could teach you. What hadn’t he done? The first American spacecraft to land softly on the moon? The one that would figure out if the descending Eagle would actually land or just . . . keep landing? That was a John Casani probe. The Ranger missions to map the moon? Casani. The Mariners, Surveyors, Pioneers, Voyagers, and Vikings? Also Casani. Galileo and Cassini? Casani and his three fellow pillars of JPL had touched everything, had seen it all, success and failure. The chance to work with such an engineer and learn from him? Karla didn’t know if the project would last three months or fifteen years, but she agreed on the spot.

  And she was not disappointed. Watching John Casani work was a master class in teaming and project management. The way he built bridges between scientists and engineers. His interaction with aerospace contractors. To see how he managed the political part of Prometheus, unifying major NASA centers (erstwhile and elsewhere mortal combatants for slices of the agency’s pie). Integrating the U.S. Navy reactor cadre. The way he treated people as a team of interlocking professionals in service of the impossible, and how he forged bonds between them—Karla absorbed every lesson she could.

  What she learned remained relevant after the later deaths of Prometheus and JIMO. With the battlestar concept filed away indefinitely, and eight years now removed from the Great Gravity Assist Panic of 1997, NASA was willing again to stipulate on mass and radioactive power sources. This gave engineers a freer hand to incorporate heavy shielding, saving the mission millions otherwise spent hardening individual spacecraft electronics on a microscale, and they applied their new liberties to a small, internal study that resurrected the orbiter concept of old. Even as the engineering made headway, however, the Europa project was missing something other than NASA’s money—some spark, a wild card, a part that could make for an exponentially bigger sum.

  Enter Robert Pappalardo.

  It was a real coup in May 2006 when Gregg Vane, a manager in JPL’s Solar System Exploration Directorate, hired him. The lab needed a scientist to put Europa on a war footing, and Bob’s arrival was a sign from above that management meant for this mission to happen. It was better still that he and Karla hit it off from the start. The lab had made it clear that if a mission flew, Bob would be the project scientist. (They made no such promises to Karla, though she aspired to be the project manager by launch.) The two roles were complementary. The project scientist—always a scientist—oversaw all decisions affecting the project science. The project manager—usually an engineer—was in charge of delivering the spacecraft on time and on budget (“time” and “budget” both being defined by the Powers That Be). In Bob’s view, both were simultaneously in charge, by necessity—ensuring the scientific integrity of a science mission required coequal footing with the one delivering said spacecraft.231 In keeping with this logic, a compatible project manager and project scientist could achieve anything. If they hated each other, however . . .

  Bob worked in the science building and Karla worked nearby in Building 301, mission formulation. Her knowledge of How Things Work was as good as anyone’s at the lab, and she knew everything necessary to get the agency to bite on a mission concept. When it came to icy satellites, meanwhile, he had revised the story of the Europan ice shell, hypothesizing that it operated by way of solid-state convection: i.e., Europa’s ice shell is like a lava lamp, with relatively warm, slushy spots in the lower shell rising upward, and cold, hard regions at the top sinking lower. And while top-tier scientists could sometimes be abrasive, Bob didn’t talk down to anyone. The pairing was a sign from above that these endless explorations of Europa mission concepts were not exercises in wheel spinning. You didn’t entice someone like Bob Pappalardo away from the soft life of academic tenure if you didn’t plan to use him.

  Europa science when Bob met Karla was much improved from when Bob met Carl. What started as an image of a stunning, scratchy, blurred ball taken twenty-five years earlier by the camera of Voyager 2 was now a real world in space starting to make sense. There were maps now, and you could slap them on a desk, point with a flourish at features, plan your attack. What is this and why? There were hypotheses for Europa’s inscrutable lineaments—an appreciable achievement for a world that once made no sense at all, lacking anything comparable in the known universe. And things had names now! On Earth, Africa and Everest and Loch Ness and the Seine and the Amazon and Egypt and the Pacific—they just always were. But Europa was tabula rasa. So there was Cynthia Phillips, a second-year graduate student in the nineties at the University of Arizona—an affiliate member of the Galileo imaging team, lowest-ranking person in the room, and doer of grunt work—and there was no real role for her here at this stage in her career, and so she made one for herself, taking data beamed back to Earth from the spacecraft Galileo and uploading them to the file server for scientists nationally to begin to study, and while she was there, she pieced together the pictures, and she named things. Just like that! Craters, it was decided, would be named from Celtic mythology. That area is called Deirdre, said Cynthia.232 There is Maeve. That is Gráinne. Millennia from now, when wondered by all why we called this Europa mining town Maeveton—we call it that because Cynthia decided that that would be its name. She drew heavily on heroic women in particular. She pulled in data from the Voyager archives and pieced together the best map of Europa in existence and the baseline for the mission going forward.

  But a map of what, exactly? Europa’s giant slabs of ice were definitely pulling apart. You need never have audited a geology class to see where they separated, and that something rose from below to fill the resultant cracks. But here was a problem on Europa: while there were all sorts of places where the sheets were plainly pulling apart (called extension), there was no evidence of places where they pushed together (called contraction). The whole moon was made of these giant sheets—there were no blank spots on the map—so, by definition, they had to push together somewhere, but for twenty years, nobody could figure out where.

  Louise Prockter and Bob Pappalardo figured it out.

  That their breakthrough involved extension and contraction seemed appropriate given that their relationship oftentimes worked the same way. The Europa community was small, and the upper echelon of icy satellites scholars smaller still. You worked closely with each other, saw each other at conference after conference around the world. You saw colleagues more often than you did some family members, and sometimes more often even than family members with whom you lived. Clashes could be familial and thus titanic. Louise and Bob both wanted the best science possible, and when they disagreed, they disagreed. When Louise asked Bob to meet her at the 1999 American Geophysical Union conference in San Francisco about something she had discovered in the Galileo data, he was hesitant; they hadn’t really spoken in months.

  The conversation went something like this:

  —Bob, I think I found something.

  —Whatever.233

  But he agreed to meet with her. It was the cusp of Y2K, and maybe all the world’s computers would stop working and the apertures capping nuclear silos would open and end the dreams of our ancestors. Or maybe not—it was in the hands of COBOL developers now—and meanwhile, the annual geology conference went on as normal. (Geology played the long game, after all, would survive doomsday in any event.) At AGU, dozens of talks were given simultaneously in fifteen-minute bites, one after the other eight hours a day for a full week—thousands upon thousands of scientists revealing results to colleagues, with ancillary meetings held throughout for various concerned parties, and poster presentations were spread across one million square feet of the Moscone Center. It could be crowded.

  The two met at the top of a quiet, remote set of escalators, taking seats on an adjacent staircase. Louise pulled out her laptop and brought up an image of Europa’s surface. Right there, Bob: that’s a fold in Astypalaea Linea. (Latin for “line,” and referring to long line-like geology.) It’s compression. Louise was a geomorphologist: her job was to lo
ok at a surface and tease out its history. Bob, meanwhile, was of the Carl Sagan school of extraordinary claims requiring extraordinary evidence, but he saw it, too: there was something there.

  And together now, they pressed forward. You’ve seen something, but what does that mean? They wrote the paper quickly—collaborated brilliantly—understood each other and the implications of the work, this key part of the Europa story, and they found more evidence yet at Libya Linea. The paper was published in the journal Science, where neither of them had been published previously or so prestigiously, and suddenly they were doing interviews with beat journalists in the national press.234 It was Dr. Prockter’s first-authored-paper debut.

  Scores more would be written post-Galileo, as scientists squeezed the sum of Europan scholarship dry. Bob had published on solid-state convection in Europa’s ice shell, and he developed the science of Europa’s subsurface ocean. Geoff Collins, their former colleague at Brown, and by then an assistant professor of geology at Wheaton College in Massachusetts, was looking at chaos regions on Europa and how hydrothermal vents on Europa’s seafloor would and would not affect the ice shell above.235 Greg Hoppa, a principal system engineer at Raytheon and a former student of famed orbital dynamicist Richard Greenberg at the University of Arizona, was working out the origin of the moon’s cycloidal ridges—bizarre, connected scallops, like the open sea as depicted in a child’s drawing, hundreds of miles across—helping explain the way daily tidal stresses made tectonic features on Europa.236 Little by little. This explains that. That tells us this. How much heat does this motion create? How would that affect the ice shell?

  Meanwhile, back at the lab, Bob toiled tirelessly on the most ambitious activity of his life: he had decided to write the book on Europa. It began as a series of papers he drafted while standing up a Europa lab for JPL, summarizing where the planetary science community was in its thinking about the icy moon. Alan Stern’s 1997 textbook, titled Pluto and Charon: Ice Worlds on the Ragged Edge of the Solar System, which similarly assessed the state of thinking for those two worlds, had helped organize and galvanize scientists interested in the Plutonian system. Indeed, Stern’s book, as part of a wider push by guerrilla outer planets scientists parachuting into space conferences to explain their work and what more needed to be known, led ultimately to a decisive endorsement by the Decadal for a medium-sized mission there, which led to New Horizons. It was clear to Bob that Europa scholarship had reached a similar level of maturity, and he reached out to the University of Arizona Press, publishers of Stern’s book, pitching one similar but for Europa exclusively. The negotiations were quick (“You’ll write it for free.” / “OK.”), and Bob approached two coeditors: Bill McKinnon, a professor of earth and planetary sciences at Washington University at St. Louis (who also coedited Fran Bagenal’s Jupiter book), and Krishan Khurana, still of UCLA. Three weeks later, they had written a proposal and submitted it to the publisher. It was accepted shortly thereafter. At no other time in human history could these books—the Europa book, the Pluto-Charon book, the Jupiter book, and a growing library of others—have been written. It was only with the launch of spacecraft and space observatories that the knowledge within their pages was attainable.