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.
Chapter 3
The Dark Ages
FOR PLANETARY SCIENTISTS, THE JIMMY CARTER–Ronald Reagan years were in retrospect like the Dark Ages, and they, the monks tending in enclaves to the embers of civilization.68 For a solid decade starting in late 1978,69 NASA launched no planetary science missions, and pretty much the only space science data trickling back to Earth came from the Voyager 1 and 2 flybys of the farthest planets of the solar system, where you’d get three weeks of data and then three to five years of silence—hardly enough to sustain an entire field of scientific inquiry.70 The Voyager findings at Jupiter fueled a desire by the careworn planetary science community to return there, but that required Reagan to fund the spacecraft Galileo—something his administration worked diligently to avoid doing upon assuming power in 1981. The new president believed he had a mandate to slash nondefense spending, and he was following through, and if you weren’t building bombs, battleships, or Black Hawk helicopters, your budget was up for grabs—and grab they did. While NASA’s top line fared well overall, that money was directed largely to the space shuttle program, which had become something of a flying Statue of Liberty in the public imagination.71 Anyway, the shuttle had military applications, including the deployment of spy satellites72 and, on paper at least, stealing satellites from foreign governments.73 The supply-side marauders would still get their squeeze from the agency, however, and that meant science. Before the toner was dry on new presidential letterhead, the White House told NASA that of Galileo, the Hubble Space Telescope, and the joint NASA–European Space Agency International Solar Polar Mission to study the sun, it could keep two (for now). And just like that, Solar Polar was gone. The Europeans had invested in it more than one hundred million dollars, and America thanked them for the trouble by withdrawing without warning, leaving the Europeans seething.74 The slaughter continued with the spacecraft VOIR, the Venus Orbiting Imaging Radar: vaporized. This cancelation, too, went over poorly. If the Solar Polar abandonment was an uninvited concupiscence thrust upon America’s allies abroad, the Venus cancelation was at least a rude gesture suggesting the same to planetary scientists at home.
But that Galileo mission—how it vexed and annoyed the White House. How the administration wanted this half-billion-dollar monstrosity slain! This expedition to Jupiter . . . we—we’d just been there with Voyager! Why were we even talking about this? So the Office of Management and Budget zeroed out Galileo in its tentative plan for the agency.75, 76 As for those twin spacecraft Voyager: What, exactly, was there to learn about planets past Saturn, anyway? Uranus! Neptune! Did it matter? I mean, come on!77 Just issue the shutdown command, and we could also switch off this devil-begotten Deep Space Network as well, those gigantic, twenty-story radio dishes required to talk to them. That’s two hundred twenty-two million dollars saved overnight.78, 79 Between Galileo and Voyager, we could cut costs by a half billion.
To somehow save what was becoming even to outsiders a sinking ship, the public started pitching in. In one instance, Stan Kent, a California engineer, created what he called the Viking Fund—a private, pass-the-hat effort to cover costs for Deep Space Network downlink time for Viking 1, the last surviving spacecraft on the surface of Mars. Donate now to feed a starving robot—send checks to 3033 Moore Park Ave. #27, San Jose, CA 95128.80 The Viking program had once been the zenith of NASA space science, the most ambitious agency endeavor since the Apollo program, and, when conceived, a prospective precursor to Apollo’s obvious heir: human missions to planet Mars.
Between 1965 and 1976, NASA had sustained a steady sequence of sophisticated Mars probes. Mariner 4, a flyby in 1965, was humanity’s first successful encounter with the Red Planet. Mariners 6 and 7 followed four years later, imaging up close the entire Martian disc, and those images, stitched together, revealed a real rotating planet—just like Earth.81 Mariner 9 in 1971 was the first spacecraft to enter orbit around another planet, mapping Mars in high resolution and capturing dust storms and weather patterns. Like elapsing lines in the book of Genesis, each spacecraft in succession made Mars a world as real as our own. By the time the Viking landers left launch pads at Cape Canaveral in 1975, no hope remained for extant alien civilizations, but flora and fauna of some form were still on the table. And the question remained—the ultimate question—the same that had fueled fiction and stirred scientists for centuries: What did that Martian wildlife look like?
The American space program has always marched inexorably toward Mars. Before the Eagle landed—before the first naut, cosmo, taiko, or astro—before Sputnik—before even the formation of NASA itself—there was Das Marsprojekt, a work of speculative fiction by Wernher von Braun, the German rocket scientist relocated to the United States immediately after World War II. No mere thought experiment or flight of fancy—no ray guns, no saucermen—the plot was a thin veneer over How to Do It, and the author the person most likely to make it happen. Von Braun wrote Das Marsprojekt in 1948 after finishing work reconstructing for his new American hosts the V-2 rocket, a ballistic missile he helped develop during the war. The book was later stripped of its fictional elements, and much of it repurposed as a nine-page article in the April 30, 1954, issue of Collier’s Weekly, then one of the most popular and prestigious magazines in the United States.82 The first serious study of how to get to Mars, von Braun’s plan involved a space station and a flotilla of reusable rockets and shuttles, and necessitated a crew seventy strong for a Martian stay exceeding one Earth year. Upon arrival, astronauts (well, “spacemen”—astronauts had not yet been invented) would enter orbit and scout suitable set-down sites for the human beachhead. (He didn’t discuss robotic exploration because digital, programmable robots had not yet been invented, either.)
For von Braun, Mars was always the plan, the moon merely a waypoint, and fourteen years later, when Armstrong leapt from that bottom rung of the lunar lander ladder, it was von Braun’s Saturn V rocket that got him there.83 He (i.e., von Braun) was by then director of NASA Marshall Space Flight Center in Huntsville, Alabama, de facto “father of the American space program,” and a minor celebrity. He had made multiple appearances years earlier on a 1950s television show called Disneyland—hosted by Walt himself—selling to forty million Americans the notion of robust, reliable rockets, moon shots, and Mars colonies.84 When the shows aired, Yuri Gagarin was still an obscure pilot in the Soviet air force, and Alan Shepard a test pilot in Maryland. To the extent that Americans were even aware of U.S. space ambitions, it was von Braun soft selling Mars missions with Walt Disney. He had been working toward this for a very long time.
It was thus unsurprising that two weeks after American silicone soles pressed prints into fresh moondust, von Braun stepped into Spiro Agnew’s office and slapped onto the vice president’s desk the next natural frontier for American exploration: the Red Planet.85 The fifty-page presentation—the definitive plan to make mankind multiplanetary—represented the culmination of von Braun’s life’s work. His prescription involved many of the elements he had proposed decades earlier: the rockets, the shuttles, the station—even a nuclear-powered spaceship.
Unfortunately for von Braun, prevailing forces in Congress and the White House came quickly to see the Apollo program as the goal, rather than, as he had hoped, an early milestone of something much larger. You didn’t build Hoover Dam and then . . . build more Hoover Dams downriver, said the politicians. We set a goal, and by God we did it. Why even have a NASA? wondered the White House aloud. By Apollo 15 in 1971, opinion polls pegged public support of space spending at about twenty-three percent, with sixty-six percent saying that spending was too high.86 There would be no national political price for closing Cape Canaveral completely. Really, what were we doing up there?
Nevertheless, von Braun’s sequence of space missions culminating in Mars exploration had so defined NASA that it was almost hardwired into the system. Nixon, h
aving zero interest in the space program but even zeroer interest in being the one who ended it, entertained only the space shuttle element as viable because it 1. had those spy satellite applications and 2. could be a major construction project in Palmdale, California, keeping his home state in his column during the next presidential campaign. So the California-made, satellite-stealing space shuttle it was! NASA lived to flight another day.
Unlike the human adventure, which always sold itself, NASA’s robotic program had a much tougher go of it, and that it survived the end of Apollo was miracle adjacent, especially since more than once it was nearly canceled entirely. Still, that twisting of Mars into the agency’s genetic code led eventually to the billion-dollar Viking program: a pair of orbiters and landers that would answer the “life question.”87 Even by Apollo standards, Viking was gutsy and glorious. Mars, engineers and scientists had determined, was one of the most difficult places to land in the solar system. You needed parachutes to slow down, but because its atmosphere is limpid and ephemeral, you still needed thrusters to take you in—and you couldn’t use both at once. Remote control was impossible because of the distances involved; computers would have to command any entry systems, and the descending spacecraft would be alive on the ground or vaporized in a hole by the time transmissions from Mars reached Earth—despite those signals traveling at the speed of light. No one even knew for sure the solidity of the Martian surface. One-third of scientists on the project thought it might have the consistency of shaving cream.88 What if Viking landed and just . . . kept landing! All of which is why NASA launched two Viking surface probes: redundancy. One would probably crash, but the mission would go on. And yet despite the challenges and uncertainties, Vikings in 1976 would achieve their most undaunted landings since Erik the Red a thousand years earlier. Viking 1 set down softly near the Martian equator at Chryse Planitia (the Golden Plain), and Viking 2, halfway around the world, in the scalloped, higher latitudes of Utopia Planitia (the Paradise Plain).
The Mission Page 6
