LOUISE PROCKTER FINISHED THE EMAIL AND SENT IT. Just like that. One sentence and a CV attachment, and it was out there now, three branches down the tree of life that sustained the American space program: Drafts to Outbox to Sent Items. She opened her planner to December 21, 2006, pressed pen to page (blue ink for Europa’s turbulent ocean, currents coursing fathoms below), and crossed it from her list of things to do that day. Volunteer for new Europa mission study. Done. From her little office at the Applied Physics Laboratory of Johns Hopkins University in Maryland, Louise worked full-time on the MESSENGER mission to Mercury, part of the spacecraft’s camera team. Her role on the project kept page after page and line after line full in her color-coded Levenger planner (Mercury in red for its intense heat), but she would fill the margins with blue ink, if necessary. I mean, this was Europa. She belonged on that study.
And why not? She’d paid her dues on the late JIMO’s science definition team, where she co-led the geology and geochemistry group. She’d planned observation orbits of the spacecraft Galileo around Jupiter before that. (Poor radiation-poisoned Galileo, asleep at last.) She’d published a steady stream of papers on icy moons, and Europa in particular. She knew more about dark terrain on Ganymede than probably anyone else in the world and had written the dark terrain section for Fran Bagenal’s book on Jupiter. The last twelve months alone, working on MESSENGER—a tortured but accurate acronym for the Mercury Surface, Space Environment, Geochemistry, and Ranging mission—had proved among the most exhilarating of Louise’s life—and that spacecraft had another four years to go before entering orbit around the planet nearest to the sun.
Space exploration was not for the impatient. It took years to get a mission approved by NASA, years further to get it built and off the ground, and except for Mars (with its favorable celestial alignments with Earth), still more years yet for it to reach its destination. In the case of MESSENGER, rather than flying directly to Mercury, which would have been faster but bananas in its fuel requirements, like most spacecraft in NASA’s fleet, it would instead pinball around the solar system using slingshot maneuvers called “gravity assists,” swinging by this planet or that and leveraging the encountered planet’s massive well of gravity and atmospheric friction to speed up, slow down, or make major trajectory changes. This allowed the vessel to carry less fuel at launch, which in turn meant NASA could use a smaller rocket to launch it from Earth, saving tens of millions of dollars.
MESSENGER’s mission plan called for the spacecraft to lift off and oval the sun until it again met Earth for a course correction that would kick it inward to Venus and again around the sun for another, more harrowing Venusian encounter (a terrifyingly low two hundred ten miles above its surface), really reducing the vehicle’s velocity now and angling it inward toward Mercury, circling the sun another dozen times, thrice buzzing the tiniest inner planet, easing, easing, easing ever so slightly into formation with Mercury, until finally, finally, finally the spacecraft might slide gingerly into the tiny planet’s ethereal orbit. The distance from Earth to Mercury at their closest was about fifty million miles. The distance MESSENGER would travel ultimately from launch to arrival: nearly five billion miles.47
So far, the vehicle had had its gravity assists from Earth and Venus. For much of the duration of these “cruise phase” operations, MESSENGER’s science payload remained active, each instrument team working full-time, including Louise and the rest of the camera crew. During the Earth encounter, the spacecraft captured two of the most stunning shots of our azure orb that she had ever seen. There it was: South America, with Africa wrapped along the lower crest of Earth like some great giant’s gentle hand holding up the world for inspection.48 And while flying away, a parting image of the Galápagos Islands gilded with a glint of sunlight.
None of this just happened, of course: the images of Earth, the orbital adjustments, the golden glint of sun. (Well, that one just happened.) It had to be planned, all of it, and rigidly, every image, every video, every second of every sequence, taken by a spacecraft speeding six and a half miles for each of those seconds, the laws of physics alone keeping the spacecraft in precisely the right place at precisely the right time. The whole point of the exercise (beyond bagging opportunistic new photos of our home planet) was to work out the wrinkles before you got to Mercury: team dynamics, mechanical calibrations, image sequence plans, camera control software development. All of it was critical to ensuring that the prime mission at Mercury moved from day one as if on rails. The work did not stop during the years-long cruise phase, and it could be spellbinding, tedious, challenging, or all three of those at once, but even with its decadal timescales, there was an urgency inherent to space exploration that energized everyone, and especially Louise, who simply could not believe that this was her life, but who never stopped to think too hard about it because there was so much work yet to be done. Earth, Venus, Venus, Mercury, Mercury, Mercury, orbital insertion—you never punched out early. And the excitement of it all, you internalized it. It became you. And eight weeks after the first flyby of Venus, one year after seeing the sun-kissed Galápagos Islands,49 you’re writing a one-sentence email to Curt Niebur at NASA headquarters, CV attached, and you’re telling the guy trying to get a Europa mission going, Hi, Curt, I would like to submit my application for membership of the SDT for the new Europa flagship study, and you add in parentheses—because, let’s face it, who in the community wouldn’t want to be on the study, and you are one hell of a Europa scientist but nothing is ever a sure thing—or the Ganymede study—I believe I could also make a useful contribution to that study, which you could, and, you add, again, because, look, you really are one of the best qualified Europa scholars out there, but I think I could make a greater contribution to the Europa study.50
And just like that, you send it and see how far you can ride this thing: in ten years, Louise had gone from undergrad to section supervisor of the Planetary Exploration Group at the Applied Physics Laboratory. So why not send that email? I mean, we were talking about Europa here. If there was a chance—any at all—of going back, she had to be part of it.
BEFORE SHE FLEW spacecraft for a living, Louise Prockter sold newspaper advertisements. To her parents’ shock and horror, she announced at seventeen that she was absolutely not going to university, and that was that—settled, over—and she found a job at a local paper in London, where she addressed envelopes and made tea for her bosses. It was 1982. The move to sales was a big promotion. They placed her in charge of the paper’s sits vac, or situations vacant—want ads for companies hiring—and she was good at her job and she had an active social life and she was well on her way, sits vac by day and antics by night and aspirin by morning. She wasn’t, she recognized at the time, a particularly good person, but rather, just a person, a Londoner, and she ran with a certain crowd, and she was muddling through, making her way. It was life.
Not long after Louise entered her twenties, a competing paper hired her to run its sits vac, and she felt good about the work she was doing because sits vac in general charged double the price of regular ads, and this was her second go at it, and to have that kind of responsibility was like a stamp of approval from the Powers That Be that she was highly competent with a sharp eye for detail, no college needed.
All good things, though, and after a couple of years, she grew restless and wanted something more out of life and she found a job selling typewriters. Olympia-Werke, out of Germany, had London locations, and where better to work in those days than the office supply industry? But Louise realized quickly that she hated calling potential clients to sell them on typewriters, and she eventually came to hate when clients called her as well and solved that problem by not answering any ringing phones in reach. She had a company car, though, and worked alone, so she spent her days driving endlessly around southeast England (that part was a pleasure), and yet few Mastertype 120i typewriters deployed to British businesses and schools can thank Louise Prockter for their presence (though they were quite nice, she had to admit, with cathode-ray-tube screens and everything). She quit after a year, but wasn’t quite finished with the office supply industry and found a job at a small manufacturer that made PVC ring binders. The job still entailed sales, though she was given charge of the company’s marketing as well, and made pretty good money. Businesses needed binders, and she had them, and if she didn’t have them, she worked at a binder factory, and so she could sufficiently solve any supply shortcoming. At twenty-four, she felt things were looking up after the typewriter debacle.
Then Prockter and her boyfriend split up after four years of dating. The two shared all the same friends, and he got them in the split, so she was not only single now, but single without any friends, and thus without her previously active social life of antics and aspirin. By day she sold ring binders, which was exciting, and by night she was bored out of her mind, which was not. Louise searched for something to distract and fill the hours (you couldn’t really work nights, even in the dog-eat-dog world of binder sales), and courses at Open University, England’s highly regarded correspondence school, struck her as the most productive option available. On her application, she checked the box marked General Science. It was—well, when she was a kid, her family wasn’t well-to-do, and London was expensive, but the museums were free. You could spend the day walking around galleries and exhibits, and nobody cared whether you had money or not. The Prockters spent a lot of time at the Natural History Museum. There was this giant skeleton of a brontosaurus on the other side of the museum entrance and a life-sized model of a blue whale alongside it for scale. (The brontosaurus-to-whale scale was roughly 1:1, excluding neck and legs.) But her scientific curiosity went beyond that. No question: whales were great, dinosaurs were great—giant lizards from millions of years ago, Fred Flintstone used one as a crane and, after work, a slide—but deeper within the museum was a geology area, and in her young mind, some part of the physical universe suddenly clarified. Rocks, realized Louise, had context. They belonged in certain places, and could only belong there, and told stories about the world they left behind. Less clear was the museum entrance itself. Louise, attired in her school uniform (black blazer, school badge on the pocket, white shirt, red tie), just couldn’t wrap her brain around it. The facility had been built in one of those gorgeous Victorian-era buildings that somehow survived World War II, and its entrance had been renovated to accommodate the public.
The doors at the museum opened on their own. You’d walk up to one, and it would slide open. Nobody controlled it. Each time Louise’s family arrived at the museum, she would try to outsmart the door. She’d walk slowly when nobody was around, creeping up to it as though she were trying to snatch a squirrel from a park bench, and it would figure out what was going on and open. She would edge along the wall so as to avoid stepping on a suspicious plastic mat in front of the door (was it pressure sensitive?), and the door would somehow figure out that there was this little girl trying to get in, and it would open helpfully. The whole thing baffled her. It wasn’t magic. It couldn’t be. It had to be science. But how? Her father was a respected engineer with a zeal for astronomy and geology (on his office wall hung a map of Earth’s tectonic plates—the large slabs of planet that slid along the molten upper mantle and compressed into mountains and subducted below for recycling—that were responsible for continental drift). He had earned a correspondence degree from the Open University, too, and throughout her childhood, Louise watched him toil on whatever assignment came in the mail, piles of papers, textbooks. She recalled her father once carving up a sheep’s brain on the kitchen table—could still smell it, in fact. Her mother was a biology teacher, and their freezer was ever in possession of one bovine organ or another, eyeballs for the next day’s class. So Louise’s decision to enroll in the Open University made sense, and checking the General Science box, doubly so.
She had to take the usual classes—physics and chemistry and biology—but one of them, earth science, was new to her. What did it even mean? For the next year, the school mailed her modules that she completed at home; little kits with, for example, mineral samples for a geology unit—her first formal study of the subject—and she would spend evenings identifying olivine and feldspar and such. To learn Newton’s laws of motion, Louise had to rig a pendulum on the doorframes and bookshelves of the new apartment she had leased using the pretty good money she was still making at the PVC binder factory. After completing each module, she would return the homework to the school for a teacher to mark, and the next assignment, toted by mail carrier, would follow. Active evenings of experimentation bled into bleary-eyed weekends, when she would wake at ungodly predawn hours to watch televised lessons broadcast by the university.
That summer, she attended a residency on the Open University campus, where she met fellow students and spent time in an actual laboratory. She loved it, the whole experience, scholarship, having friends again. She also loved her good company car and her new apartment-slash-laboratory that her pretty good PVC binder factory salary afforded. But . . . So to everyone’s shock and horror, she quit her job at age twenty-seven and enrolled full-time at Lancaster University as a “mature” student.
Little latitude was allowed in the courses chosen, or when one took them. University educations paid for by the state permitted no playing around with electives in fifteenth-century Russian folk stories, or whatever. Louise chose to study geophysics, and the modules handed down from above reflected that. Now you are taking an earth sciences module, and here are the classes you will have. Now you are taking mathematics. Now physics. The courses came at a relentless pace, with final exams given at the end of the three-year program. To Louise’s surprise, she did very well.
During her final year, she was given her first real choice, course-wise. The two available electives were cosmology and something called planetary science, the latter taught by a professor who happened to be passing through, and, for whatever reason, that was the one she chose from the catalog. From the very first class, she didn’t know-know, but she just knew—knew that this was what she wanted to do for the rest of her life. The students looked at images of planets—not even wild stuff, really, things she’d seen on TV and in magazines, but the teacher asked Louise to look closely, to ask questions about what she was seeing, and to hunt down some answers. One day he handed out a paper and assigned them to read it.51 It had been published in the Journal of Geophysical Research and was titled “Atmospheric Effects on Ejecta Emplacement and Crater Formation on Venus from Magellan.” This, he said, is everything a paper should be. It is one of the most astounding papers that—you, you should read it! This is how a paper should be written. This is great science!52
The paper looked at the morphology—the shape and the texture and topography—of impact craters on Venus, and how the planet’s atmosphere and gravity affected the meteor collisions that created them. The images it included had been produced from radar data taken by an orbiter called Magellan—those being the only type of data available for the Venusian surface—and they astonished in ways the customary images of Venus (i.e., fuzzy cloud tops as seen from space) could not. You didn’t need a doctorate to tell that the craters were weird, but also, to Louise, beautiful. They looked living, somehow. Organic. Animate. The photographs might just as easily have been found in a medical textbook.
Across sixty-six pages of small print, complete with tables, graphs, and diagrams, the author concluded that the atmosphere of Venus shields the planet from small objects from space and preserves the effects and processes of impacts that might be lost on other heavenly bodies. What a result! her professor declared. What a paper! The research that went into it! He really could not get enough of it. Much of the science was beyond Louise, but what she grasped, she grasped tightly and held close to her heart.
That paper, written by Peter H. Schultz of Brown University, changed her life. She now knew for certain what she wanted to do, what good, bare-fisted science looked like. It wasn’t some grand theory of everything, some Eureka! that solved the great mystery of the universe. It was something far more profound in implication: meticulous work conducted over a number of years to solve a small oddity on another world. How does gravity and atmosphere affect the formation of impact craters on the planet Venus? Now we knew, or, at least, had a plausible framework for understanding. The paper’s references section listed eighty-one other papers written by scores of scholars over forty years. There was at work here a Confucian interaction of generations, nationalities, and specialties of knowledge, with everyone before, and surely everyone after, driven by his or her own simple need to know the world as it is. And now Louise Prockter knew, too.
She graduated in 1994 and formally stated her intention to study planetary science. A faculty advisor suggested she apply to graduate schools in the United States, and Louise thought that was just a terrible idea. She was suspicious of the currency and leery of the American sense of humor or lack thereof. Her advisor, unsympathetic, gave her a list of names of planetary scientists in the United States and suggested she write them letters. She did, and some actually responded, including a man named Jim Head at Brown University, a graybeard and force among the chosen few in the field, and who had also once been part of the most arresting and audacious achievement of the twentieth century, if not all of human history.
It happened twenty-six years earlier, when James W. Head was himself a newly minted Ph.D. in geology and in need of a job. While flipping through a job placement book produced by Brown, he came upon a full-page advertisement that read, OUR JOB IS TO THINK OUR WAY TO THE MOON AND BACK.53 Well, who would say no to a problem like that? The page listed a DC telephone number, and he dialed, reaching a company called Bellcomm, a subsidiary of Bell Laboratories. It had been established in 1962 at the request of NASA to handle systems analysis for the agency’s program called Apollo. Bellcomm hired Head straightaway and installed him at NASA headquarters, where he was effectively an agency employee. His job: to help them think their way to the moon and back. Putting a man on the moon was going to happen, the NASA people said, but they were stuck on the “and back” part. Their immediate problem involved figuring out where an astronaut could safely land on the lunar surface, the integrity of its uppermost layer questionable. Was it snow-like or as solid as steel? This was a serious problem. All they knew for sure was that the moon was a giant rock and they needed a rock expert. That was but one problem, however. Once the Eagle landed (gently but firmly), and the astronauts saluted a flag and telephoned the president, there were still two hours and twenty-nine minutes to kill on the shortest visit. On days-long expeditions, you’d need a good deal more for these guys to do, and if you’re going to travel that far to visit a giant rock, the only science it made sense to do was geology. And so, once the lunar rigidity was worked out (provisional determination: the moon is solid), Dr. Head was told to teach aspiring Apollo astronauts geology. To his surprise, they proved the most enthusiastic student body imaginable. Give type-A personalities a job to do—tell them that only they can do it—and watch them hit the books and take up tiny rock hammers and study stones and emplace seismometers and practice pickax employment in austere alabaster environs . . . if the moon program lasted long enough, these guys would probably find dinosaur bones up there.
But it didn’t and they didn’t, and in 1994, when Louise Prockter wrote Jim Head, he was back at Brown and long entrenched there as a distinguished professor of geological sciences. He invited her to visit. She arrived that July, on what was (coincidentally) the twenty-fifth anniversary of the Apollo 11 moon landing. This seemed ancient to Louise, the Apollo program belonging somehow to the same age that produced the Wright Flyer or Amelia Earhart, but it was brought back to life for the occasion, on television and in the papers, and especially in the Lincoln Field Building at Brown, where walked the man who helped choose lunar landing spots, a literal rock star who once ran an astronaut academy. Compounding coincidence: The same week that Louise arrived, a comet called Shoemaker-Levy 9, which had been swinging around the solar system for more than four billion years, suddenly shattered into smaller pieces. A salvo of cometary fragments the size of football fields and shopping malls careened into Jupiter. It was the first time in history that anyone could directly witness the collision of two celestial objects.
The buildings of Brown University blend by design into Providence proper—little labyrinths of metal fences, manicured lawns, courtyards, and redbrick buildings—and in front of Lincoln Field the week of Louise Prockter’s arrival, scientists set up rows of telescopes so that anyone walking by could stop and see the once-in-an-eon event: the pitiless bombardment of planet Jupiter. There were folding tables lined with pizza boxes and punch cups, and music—a carnival-like atmosphere and days of celebrations for Apollo and Jupiter. For an aspiring planetary scientist, Louise had to admit, it was as though the universe and the university had conspired to make clear to her that she needed to settle in. She was home now. Providence indeed.
In 1996 she completed her master’s at Brown (thesis: “Axial Volcanic Ridge Architecture: Classification and Interpretation of Volcanic and Tectonic Features from High Resolution Sonar Images of the Mid-Atlantic Ridge [24˚N–30˚N]”). It wasn’t so much a goal as a milestone; at Brown, you enrolled directly in the Ph.D. program and earned an M.S. along the way. At the time, the NASA spacecraft Galileo—newly established in orbit around Jupiter—was gearing up for its first encounter with a Galilean moon. Brown hired a researcher named Robert Pappalardo to help Jim Head and Geoff Collins, another doctoral student, plan the imaging campaign. Up until then, Louise had focused her studies almost entirely on the volcanoes of Venus and the ocean floor of Earth. Her specialty was surface geomorphology, which meant that she looked at images from planetary bodies and studied the textures of their facades. She did a lot of mapping, and her job was to tease from them a surface’s history. She had an eye for structural geology as well, understanding surface tectonics, the fractures and faults. It was a skill that could be applied to any planetary body: Venus or Earth or Mercury or an asteroid or the moon, but once those first Galilean images arrived from five hundred million miles, the Jovian system had her henceforth.
But those images almost never happened. The spacecraft Galileo had launched from Cape Canaveral seven years earlier, and during its first eighteen months in flight, it talked to Earth using a tiny, low-gain antenna—perfect for transmitting telemetry tidbits and confirming course corrections, but not much more. It was a temporary thing, and once the spacecraft was sufficiently far from the sun and free from the attendant risk of thermal damage, engineers ordered it to open its massive, mighty main antenna dish, which worked and looked like a giant umbrella.
The robot responded that it could not.54
This alarmed engineers. This high-gain antenna was the only way the spacecraft could send data to Earth from Jupiter. It could still collect the science, but without a way of returning its findings, Galileo would be like a library that fills itself with books, locks the door, and self-incinerates.
Clues culled from spacecraft telemetry—a surge in a motor’s current here, a slight wobble there, a slowdown in spin rate—revealed that three antenna “umbrella” ribs were jammed. The reason, soon determined: dry lubricant, which got that way while Galileo sat for years in a warehouse waiting to launch. (The spacecraft, which could have launched on any big rocket, had been tied politically to the space shuttle, which needed very important missions to justify its existence. When the shuttle Challenger blew up, those very important missions were forbidden from launching while NASA conducted a years-long investigation.)
The first idea from engineers was to do what you do when any umbrella doesn’t open: close it and push it open again. The antenna actuator was not wired for closure capability, though, only opening. (On Earth, before liftoff, humans had to fold it into its stowaway position.) The next thought: spin the spacecraft sunward a few times and let the hot-cold cycle walk the ribs open. This “thermal expansion” technique was tried without success. The next notion: swing the low-gain antenna around a bit—really work it and shake up the spacecraft—and maybe motion might make the umbrella open. Six times they did this, and six times it failed. To jar the ribs loose, they then tried just jackhammering the thing open: sending spikes of electricity to its actuators. But even after thirteen thousand hammer strikes, the recalcitrant radio wave dish would not budge.55
But—and this is why mere salutatorians don’t bother applying to Jet Propulsion Laboratory!—the engineers, their pencils now nubs, their blackboards white, found a way forward, and slapped a So Crazy It Might Work on the project manager’s desk. The Galileo mission, they said, winding up for a pitch, had two major elements: 1. the spacecraft proper and 2. an attached atmospheric probe that would, on arrival at Jupiter, be launched like a torpedo into the gas giant. The probe’s job was to study Jove’s mysterious makeup and interior physics; it would live for less than an hour before being vaporized by the pressure of Jupiter’s atmosphere. Meanwhile, the observing Galileo would receive and record the frantic and increasingly desperate reports from the probe, and later, leisurely transmit that recording back to Earth using the high-gain antenna. The spacecraft’s digital recorder was an old reel-to-reel job like you might see in a police procedural. Mechanically, it worked like this: Rewind the tape. Record the data from the doomed probe. Rewind the tape and play back the data for scientists to study.
The engineers pointed out that everything on a spacecraft has a second vocation, and the tape recorder was no different. The high-gain antenna—it would never open, was vestigial now, as useful as a human appendix—was designed to deliver data to Earth at one hundred thirty-four kilobits per second—fast for 1986, when originally slated for launch, but not always fast enough.56 On occasion, the spacecraft might be commanded to collect more data during an encounter than could be transmitted straightaway—like, say, from a high-resolution image. Likewise, when the spacecraft was on the far side of Jupiter and thus unable to see the Earth, it would not be able to return any data at all. To act as a buffer during bottlenecks and blockages, the spacecraft would fire up ye olde reel-to-reel and make temporary recordings to get the antenna over the hump. It was useful, a nice-to-have.
The project manager, of course, knew all of this.
Then the pitch: Rather than use the recorder as an occasional and brief buffering mechanism, said the engineers, why not use it to record everything, continuously? The tape had just enough length to store the totality of data collected during major encounters with Jupiter’s moons (more or less). You could record an orbit, play it back to Earth, erase it, and repeat for each encounter. Rather than act as an intermediary, the tape deck could serve as a hard drive: the spinning heart of the spacecraft Galileo. As for the antenna, being limited to low gain was certainly a problem. Its present bandwidth—about one-ten-thousandth of what the high-gain could do—obviously wouldn’t work;57 it would take years for the data recorded during a single moon flyby to get back home, and the spacecraft had at least ten flybys planned in its first two years alone. The math didn’t work. But computer scientists had devised a new storage methodology and compression algorithm, and could program them into Galileo from millions of miles away, just rebuild its brain completely, one zero and one one at a time, the way you might upgrade a home computer operating system. And by cranking up the sensitivity of the Deep Space Network, the global array of giant spacecraft antennae that listened to Galileo from Earth, engineers could get Galileo above the one-kilobit mark. Its new, improvised transmission speed would thus be one-one-hundredth of what was originally planned.58 It wasn’t pretty, and thirty percent of the planned science would be lost, but it was orders of magnitude better than would be achieved otherwise. It would work. The mission could be saved by the tape recorder.
NASA gave engineers the go-ahead. Crisis averted. Fives highed. Paychecks earned. Congressional inquiries and rolling heads forestalled.
Four and a half years later, on October 11, 1995—fifty-eight days before Galileo would arrive at last at Jupiter—a computer in the Space Flight Operations Facility at the Jet Propulsion Laboratory (mission control for robotic spacecraft) said something was amiss. The spacecraft had announced an anomaly.59 A big one. A terrible one.60 Twenty-two million miles out from Jupiter, the spacecraft had taken a family portrait of the planet and its major moons and, as instructed, rewound the recorder reels to playback and return the images to Earth. This should have taken twenty-six seconds. Fifteen hours later, according to the telemetry, it was still rewinding.
This was not a very good day at mission control.
The Galileo recorder was long obsolete—had been before launch, reel-to-reel practically papyrus by then—but engineers searched high and low and found a laboratory spare that had been built for the Magellan mission to Venus. They spooled up a fresh tape, fed it the same conditions as Galileo at Jupiter, and pressed Play . . . and the tape ripped right from the reel, slap-slap-slap-slap-slap—61
It couldn’t end like this—it just couldn’t—so they continued studying the problem, piecing together trajectory clues from Galileo and comparing them with the spare on Earth. Nine days later, having disassembled and inspected every recorder component and crevice, they had a suspicion and a plan of action. Perhaps the tape wasn’t torn. The spools, it seemed, were perhaps stuck, snagged on debris from the natural wear of a new recorder never broken in, never meant for dedicated operation. If the reel wasn’t severed, and if the recorder, in fact, still worked, they could theoretically just gun it over the hill to clear the debris.
They tried it.
It worked.
Afterward, the project declared the compromised stretch of tape off-limits, which meant that much less storage and that much less science, but rolling heads and congressional hearings had been avoided yet again.62 And though crippled, the recorder was able to do its job, the data collected vastly exceeding expectations.
Some of Galileo’s most earth-shattering results came from perhaps the least obtrusive of the scientific instruments in its payload: the magnetometer, proposed by Margaret Kivelson of UCLA to study how the Jovian magnetosphere (i.e., the region of space dominated by the planet’s magnetic field) affected its moons. Magnetometers were generally afterthoughts on spacecraft—something you added because they didn’t take up much space or power—and rarely returned results relevant to anyone outside of a small community of theoretical physicists. It was a “no-surprises” scientific tool, and yet when the magnetometer returned data on Europa, it found a startling surprise indeed: an intrinsic magnetic field, which should have been impossible. Europa was far too small to generate such a field, and, weirder yet, the ice moon’s field was pointed the wrong way relative to Jupiter. The whole thing just didn’t make sense, no matter how many blackboards physicists filled, but the data weren’t lying. There it was, a magnetic field emanating from the Europan interior.
Krishan Khurana, a research geophysicist at UCLA, published a paper positing a reason: that the mysterious magnetic field flowing from Europa’s insides might be induced by that of Jupiter, suggesting a subsurface conductor of some sort.63 It was the same way an airport metal detector worked.64 Despite the name, a metal detector doesn’t detect metal. Instead, it produces high-frequency magnetic waves that pass through, say, the car key in a traveler’s pocket, inducing a little magnetic field of its own. That induced signal is what metal detectors detect. In Europa’s case, either its interior was made of copper (it wasn’t), or there was an extant saltwater ocean down there—as had long been thought but was impossible to prove. But a quirk of Jupiter’s physics presented an opportunity: the massive planet’s magnetic field was tilted by ten degrees. If Galileo took measurements of Europa when the icy moon was on the other side of Jupiter’s field, and Europa’s field flipped, you had evidence of induction and, consequently, of an ocean. Kivelson, as instrument principal investigator, made the case to the Galileo project management for further measurements, and it was a hard one, because the spacecraft was by then limping along and radiation poisoned, flying on borrowed time. We waste this observation, and we lose a textbook of information. But she was insistent, the way only a genius seventy-one-year-old space physics pioneer could be, and she prevailed.
It was worth it. Until Galileo, though physics certainly suggested an ocean inside of Europa, it might well have frozen solid hundreds of millions of years earlier. In 2000, doubts were dispelled when Kivelson published a paper presenting the first direct evidence of Europa’s subsurface ocean.65 The magnetic field flipped, as hypothesized, which meant the ocean was extant, liquid.
And where there was water, there was life.
Six years after Kivelson’s paper made manifest the need to explore Europa in earnest, Dr. Louise Prockter’s outbox still hummed in her office at the Applied Physics Laboratory.
The next day, she received her reply from NASA headquarters.
From: |
Niebur, Curt |
Sent: |
Friday, December 22, 2006 3:31 PM |
To: |
Prockter, Louise M. |
Subject: |
Re: SDT membership application |
Importance: |
High |
Louise,
Are you interested in a joint appointment as a member of the Europa SDT and cochair of the Ganymede SDT? Dave Senske of JPL will chair with you.
Thanks,
Curt66
Replied Louise: “Yes please!”67 And now it was her job to get NASA back to Jupiter.