The Mission

by David W. Brown

  Everyone from the radar team stand up . . .

  Now everyone from the camera team . . .

  . . . and so on, and at the end:

  Now everyone stand up. That is the last time we are going to introduce ourselves as a member of an instrument team. We are one team. We are the Europa science team.

  EUROPA NEVER STOPPED tempting. In 2014 Louise Prockter discovered plate tectonics on the icy moon. It was a spare-time thing. She just saw this section of its ice shell, and it made sense. She met up with a colleague, Simon Kattenhorn, at a conference. He had written the chapter in Bob’s book on the tectonics of Europa. She knew he had never worked so hard on anything in his life as he had on that chapter, and he was justifiably proud of it, and he was very emphatic in stating in the text—unambiguously, so there was no doubt on anyone’s part—“The upshot is that there is no indication of a terrestrial-like, global plate tectonic system on Europa.”536

  And here was Louise, holding these pictures.

  Look at these features, she told him, showing him an image taken years earlier by the spacecraft Galileo. They look like subduction zones on Earth.

  Simon’s initial reaction was that it was probably a complete coincidence. But then he really, really looked at it.

  I don’t know what’s going on there, he said, but it’s weird.

  They spent the next year corresponding, sending Photoshop-processed images around, trying to work out what was going on with the ice shell. He had a sabbatical coming up and joined her for three months at the Applied Physics Laboratory, where they could figure it out in person. Louise at the time was still leading the Europa science definition team and working as deputy project scientist of the MESSENGER mission to Mercury, and so Simon took the reins on the work. They printed out images of Europa and Simon then literally cut apart its ice shell with scissors, sliding plates around until there was no longer any doubt that large portions of the icy moon’s surface were vanishing. And if they were vanishing, there was only one place for them to go: down.

  It was exciting. It was terrifying. They developed a litany of lines of evidence. Louise called it “career-ending stuff,” because Earth was the only known world to possess plate tectonics, and if they were wrong, the best case involved colleagues calling them deranged and wondering how they got this far without people realizing what lunatics they were.537

  To find the first non-Earth world with plate tectonics was heady stuff, but more important: if Europa had plate tectonics—if large plates of ice were being pushed beneath other plates—it meant that stuff on Europa’s surface was being pushed into Europa’s interior. The severe radiation environment around Jupiter created oxidants on the surface, which would be necessary for Life as We Know It to take hold in the ocean. But the radiation penetrated only the first ten centimeters of an ice shell twenty kilometers thick. Those oxidants had no way to get into the water—until now. The plates were pushing those oxidants into the ocean; the whole world was a veritable oxidant conveyor belt!

  The paper was published in Nature Geoscience in 2014 and kept the Europa conversation moving forward.538 Europa Clipper would provide exponentially higher-resolution images than Galileo and allow for their hypothesis to be tested. The things no one knew for sure about Europa were precisely the reasons that NASA needed to go back.

  LOUISE, FROM THE front row of the basement auditorium of Building 321, looked around the room at her fellow members of the Europa mission, and, yeah, this was real. After all this time. Bob was in perfect form—it was a brilliant beginning, the bone, the monolith. There were so many scientists there that day, many of whom had never done anything on Europa before. Maybe related things, but now that everyone was in the room, it felt good, but it felt a little weird, too. Almost like the new faces were intruders in some way—that wasn’t the right word—it’s just that the core group had been working together for so many years. There was Don Blankenship. He’d been doing this since 1998! She met him on the JIMO study, and they had worked together on every study ever since. All these people—every mission had its own personality, and she was swept briefly with melancholy that this one would soon change. Which was good! The mission would evolve and grow into the future, into what they had all been working toward for fifteen years.

  Part of it, I guess—how could anyone ever know what they had gone through? No one would ever know the trials endured to get everyone into this room. I mean everyone knew about the troubles getting a proposal going, but they weren’t there. They heard updates from the OPAG meetings once a year . . . a couple of slides, and that was it! But it wasn’t their lives; it was hers, and Don’s and Dave’s and Bob’s. She felt suddenly like the veteran of some horrible war. It had been such a huge part of her career, had taken so much, and would demand so much yet, that even now, it was real—but it wasn’t a relief. Until she got those images back from Europa, she might never believe they had done it. Maybe even then she wouldn’t believe it. She had internalized the setbacks. And until those data were on Earth, in computers and being processed, so much could still go wrong. For the next . . . ten years? Fifteen? She would never be able to sit back, kick off her shoes, and say, I’m done now. Because she was not. They were not. She did not come this far to only come this far. And this is where it would start to get really, really hard, because now they had to make the difficult decisions. Before, they were trying to move it forward, streamline it, hone it, and sculpt it into this amazing, beautiful, irresistible thing to NASA that was going to go and do unbelievable science at this unbelievable moon. But all that, all the years and tears, it wasn’t to get to Europa. It was just to get into this room.

  Surrounded now by her colleagues in the auditorium, it was good. Now there would be new ideas, better ideas, from some of the best scientists in the world, and they would want to understand why the Europa leadership had made the decisions they had. Suddenly, you were—it was like getting married. You’re where you want to be, but now you’ve got a whole new family to learn about and work with, and some you were going to get along really well with, and some . . . not so much. Everything was different now. It was exciting, though. So exciting, to finally be a real mission. After all this time. It was going to happen. They were going to study Europa, its geomorphology. Its shell. Its ocean.

  She had once been to the bottom of the ocean on Earth. Her initial research at Brown University involved the study of volcanoes on Venus and how they compared with volcanoes on the midocean ridge, mountain chains on our ocean floor. The job required countless hours of mapping sonar data taken from the bottom of the sea and comparing them with radar data from the surface of Venus. One day during a talk, her doctoral advisor, good old Jim Head, let it drop—but casually, because he was nothing if not charming and ever a showman—that one way to study how volcanoes might form in a pressurized environment like you see on Venus is to study their analogues on Earth, and, oh, he had already set it up: they were going to take an Alvin deep-sea submarine to the floor of the Pacific Ocean.

  The bottom of the ocean, Louise learned, was like being on another planet, and the dive down was like getting there.539 They departed from port on the RV Atlantis, a research ship with a crane attached, and the Alvin attached to that. Their target was the East Pacific Rise, where met two tectonic plates beneath the surface of the Earth: the Pacific Plate and the North American Plate. They were looking at hyaloclastite flows—something like Washington State’s Mount St. Helens, but on the ocean floor. Where magma erupts into the water, it shatters into billions of pieces, and they begin to settle. She was there to observe and drill into one of those hyaloclastite volcanoes.

  There were two others on board that day: an oceanographer from Monterey Bay Aquarium, and the pilot. It was the first day that Louise wasn’t seasick, thank God, and the way it works is that you get in the submarine, and they lower you into the water, and you just wait for a bit, bobbing around, mostly to make sure you’re not claustrophobic or in danger of losing your mind, because there
are three people crammed into a few square feet, and you’ll soon be surrounded by one hundred eighty-seven quintillion gallons of water one mile below sea level. You’re wearing jeans and sweatshirts, because it gets cold down there, but no shoes, because you’re not really walking around or anything. You don’t drink anything the night before or the day of, because there aren’t facilities down there (they really drive home that point in the paperwork), and when you get in the Alvin everyone respects everyone’s personal space, limited though it may be.

  Then you start to sink. The sunlight can still penetrate the water for the first fifty meters, and it’s alien already, fluorescent flecks all over, biota of some sort. You continue sinking for hours, and soon it’s pitch black and you’re just sitting there, chatting anxiously, and when you reach the bottom of the ocean, the pilot turns on the headlamps, and it is nothing like you expected to see. It’s white rolling dunes all around you—more like the desert, really, than anything—and every now and then you see some weird whitish translucent creature creep by. It’s not heaving with life, fish everywhere. It’s more severe than that, but what you see, suddenly you’re playing Twister with your newfound friends to peer from the tiny portholes. And then you’re sampling, trying to drill into the hyaloclastite, and having a hard time collecting core samples with your robotic arms. It’s lunchtime, and you’re eating sandwiches at the bottom of the Earth. Once air runs low and enough is enough, you rise to the surface, sinking in reverse. The pilot let Louise drive the submarine for a bit, but she was rubbish at it. (It looked so easy.)

  The bottom of the Europan ocean would likely look nothing like the one on Earth. The fine sandy stuff forming dunes down and along our ocean floor was composed of bits of shell, sand, and sea creature. It’s all weathering and decomposition down there. The seafloor of Europa would be rough, more Martian than not. There’s no weathering, no ground-up pieces of stuff settling out.

  Unless there’s life. Then it’s anybody’s guess.

  Acknowledgments

  This book could not have been written without the support of the planetary science community, and especially Louise Prockter, Bob Pappalardo, Don Blankenship, and Curt Niebur. Seven years is a long time to answer anyone’s questions.

  My sincerest thanks go to Geoff Shandler, who acquired and edited this book, working miracles with those blue and red pencils. Thank you for your encouragement, kindness, and craftsmanship.

  I am indebted to the team at Custom House—particularly Peter Hubbard, for adopting this book as your own and bringing it to shelves; Ben Steinberg and Kelly Rudolph, who have worked so hard to make it a success; and Molly Gendell, keeper of all knowledge.

  Thank you to my agent, Stacia Decker, who made this thing happen, and whose superpower is talking me down from ledges. I am grateful also to Shannon Stirone, for sage advice during composition, and to Kris Gallagher, who has been there from the start.

  Lastly, thank you to Kelly, Alexander, and Amelia, for your love and support, and for living with this project for so many years.

  Notes

  1.K. K. Khurana et al., “Induced Magnetic Fields as Evidence for Subsurface Oceans in Europa and Callisto,” Nature 395, no. 6704 (1998): 777–80, doi:10.1038/27394.

  Khurana’s paper in Nature was the first to posit that an odd, unexpected magnetic field found at Europa by the Galileo magnetometer is not intrinsic, or borne from within, but rather is induced by Jupiter’s magnetic field, in the same way that an airport body scanner induces a magnetic field in the keys you are carrying in your pocket. The only way such a thing could be possible would be for Europa to either be made of copper, which it wasn’t, or for there to be a liquid, subsurface ocean on Europa, which, apparently, there was.

  2.M. G. Kivelson et al., “Galileo Magnetometer Measurements: A Stronger Case for a Subsurface Ocean at Europa,” Science 289, no. 5483 (2000): 1340–43, doi:10.1126/science.289.5483.1340.

  Margaret Kivelson, as principal investigator of the magnetometer instrument on Galileo, would later convince the project to fly the spacecraft in a particular orientation in order to test the ocean hypothesis. Because Europa’s magnetic field is tilted, by flying on the other side of the tilt (versus the trajectory of the initial measurement), the magnetic field would flip if it were induced. They flew on the other side of it. It flipped. The experiment proved successful, and Kivelson thus discovered the second global ocean in the solar system—the first, obviously, being on Earth.

  3.R. Pappalardo, telephone interview by author, April 7, 2015.

  See also J. Moore, telephone interview by author, July 17, 2017.

  4.G. Vane, email message to R. Pappalardo regarding the lunch conversation at SSES, November 16, 2004.

  5.R. Pappalardo, telephone interview by author, October 27, 2017.

  6.M. J. Rutherford and P. Papale, “Origin of Basalt Fire-Fountain Eruptions on Earth Versus the Moon,” Geology 37, no. 3 (2009): 219–22, https://doi.org/10.1130/G25402A.1.

  7.W. N. Charman and C. M. Rowlands, “Visual Sensations Produced by Cosmic Ray Muons,” Nature 232, no. 5312 (1971): 574–75, https://doi.org/10.1038/232574a0.

  8.R. Pappalardo, telephone interview by author, April 8, 2015.

  9.J. Achenbach, “NASA’s 1976 Viking Mission to Mars Did All That Was Hoped for It—Except Find Martians,” Washington Post, June 18, 2016, https://www.washingtonpost.com/national/health-science/nasas-1976-viking-mission-to-mars-did-everything-right—except-find-martians/2016/06/18/749701f6-2c15-11e6-9b37-42985f6a265c_story.html.

  10.R. Pappalardo, interview by author, March 7, 2017.

  11.“Longs Peak—Keyhole Route,” National Park Service, last modified June 5, 2018, https://www.nps.gov/romo/planyourvisit/longspeak.htm.

  12.There was a real art to helping a grad student reach his or her potential in planetary science. A student comes along and says, I am interested in Europa, and Bob says, OK, why? and the response would be his guide. Here is a possible project. Let’s see what evolves. Or a student would have a particularly strong skill set (or an interest in cultivating said skills) and that could lead to interesting things, too. He might be at his desk during office hours and receive an email from the Canadian Geological Survey. Hey, Bob, we wrote this paper on the Canadian high Arctic that might be of interest to you. (Frozen parts of Earth being a good place to study frozen worlds less accessible.) A year later a grad student materializes and says, Dr. Pappalardo, I am interested in Europa, and Bob says, What are you interested in, exactly? and the student says, Well, I’m interested in Earth analogs, and I’m taking a remote sensing course now and I like that. Well, says Bob, there’s this weird site in the Canadian Arctic that might be a good analog for Europa—why don’t you look at the paper and tell me what you think from a remote sensing standpoint. The student goes on to research, say, the deposits of sulfur present in the Arctic site, and gathers existing satellite data, and one thing leads to another. Bob is writing grants now, to get her out there to do some field geology, and linking her up with the Jet Propulsion Laboratory people who can actually take those remote sensing spectra from satellites and who are working on identifying sulfur-rich deposits from orbit autonomously.

  A student comes in and says, I’m interested in Europa, and I’m also interested in programming. Bob thinks for a moment and says, Well, OK, maybe you can write a program to map the structural features on Europa to compare them to the stress patterns predicted from existing models. There’s a group at the University of Arizona doing it, but they shouldn’t be the only ones in the universe who can calculate Europa’s surface stresses, right? Let’s see if we can duplicate that model. Once the project is under way, Bob mentions it to a geophysicist colleague who says, THAT IS NOT HOW YOU DO THIS! VISCOSITY IS CRITICAL! IT’S NOT JUST AN ELASTIC PROBLEM! (this is how geophysicists talk) and the student and the geophysicist link up and develop something better than any previous model to come before.

  That is how science is done.

  13.R. Pappalardo, telephone
interview by author, December 29, 2017.

  14.J. W. Wood, Pasadena, California, Historical and Personal; A Complete History of the Organization of the Indiana Colony, Its Establishment on the Rancho San Pascual and Its Evolution into the City of Pasadena Including a Brief Story of San Gabriel Mission, the Story of the Boom and Its Aftermath, and of the Political Changes and Personages Involved in This Transformation: Churches, Societies, Homes, Etc. (Pasadena, CA: s.p., 1917).

  This is a remarkable account of how Pasadena came to be, worth reading for its historical scholarship as well as its literary merits. Concludes the author, J. W. Wood, of his beloved city: “But of the future! It may require no prophetic vision to see it. Invention and genius, well applied, will confer their magic, and we can in our horoscope, discern clearly a rehabilitation that will give to this community a new fame.” How right he was! The book is now in the public domain and may be downloaded in its entirety from Google Books. And in case you are wondering: yes, the title of the Wood book—about a Pasadena mission—inspired the subtitle of this book, about another Pasadena mission.

  15.The settlers from the northeastern United States arrived on horseback and in carriages, buggies, and wagons drawn thereby, and they sought a new life—amazing that nobody had settled this land before!—and in 1874 established the Indiana Colony on land that had long been parceled from the dominion of the Mission San Gabriel Arcángel. It would be work to make this thing a success, Indiana Colony. Nearby Los Angeles, after all, wasn’t much to look at, crude and bedraggled, but my God, this California sun! Have you ever seen anything like it? The colony did well enough that first year, and when at last it petitioned for a post office, the postmaster general cast eye across application and returned it rejected. What kind of name was “Indiana Colony”? You didn’t arrive by Mayflower, people; try again. So the settlers settled on the name “Pasadena,” on recommendation of a friend of a friend, a missionary working with the Chippewa in the Mississippi Delta. We want something that sounds really Indian, you know? Something that means “entrance to the valley” or “crown of the valley.” Something like that. And the missionary, his hands mostly tied because, I mean, come on, returned the requested translations: Weoquanpasadena or Tapedaegunpasadena. But that wasn’t really what the villagers of Indiana Colony had in mind, though the “pasadena” part was quite lovely, wasn’t it? Which translated from the Chippewa language more literally as “this is a valley,” but I mean it’s not like any Chippewa lived in California, so who would know? Pasadena, California it was.