Nothing in the Grand Tour, perhaps, was more daring than the hope—the planned expectation, really—that the spacecraft could in fact acquire the additional data it needed for precision guidance. The engineering term “critical late activities” disguised the audacity behind the ambition. The particular issue was that the spacecraft’s navigational system could not work reliably from Canopus alone; it needed other bodies, preferably Neptunian moons, objects that were not, at the time, known to exist but whose identities were programmed blankly into Voyager’s computers. If—when—such satellites were discovered and their orbital parameters measured, the additional information would be uploaded into the code. Voyager 2 needed at least one such moon; it found six. It then needed to tweak its trajectory to thread the Neptunian needle. It planned for six corrections, the first coming on February 14, 1986, a scant three weeks after the Uranus encounter. It needed only four.195
All this of course required smart sequences uploaded to an onboard computer command subsystem that dated to the Paleolithic age of computing by a cobbled-together array of DSN dishes that spanned from Japan to Australia to California and New Mexico. By 1989 Voyager 2’s computers were nearly as creaky as its scan platform rotors, and its onboard memory was an order of magnitude less than that of even the lower-end personal computers then available. Still, JPL planned ten uploads of command sequences, the product of “high-fidelity timelines” translated into machine language and the outcome of nearly thirty-six months of intense labor.196
In the end, the reality was that robot and handlers would have to rely on each other—Voyager 2, that JPL could tell it what it needed; and JPL, that Voyager 2 could operate autonomously, for once the spacecraft commenced near-encounter, it would be on its own. The distance between Neptune and Pasadena was such that even a simple transmission would take 246 minutes, or over four hours, and for a full exchange, 492 minutes, assuming that a response was instantaneous. So among its programs were “failure [or fault] protection algorithms,” which would allow Voyager to detect and repair many problems, or shunt into a safe mode. There were, for example, routines to have the spacecraft begin a sequence of pitches and yaws to relocate the Sun, and then roll to refix with Canopus should something break navigational contact. The computer often tested itself. Critical instruments could be shut down and then reignited in the event of voltage surges. And a “backup mission load,” frequently uploaded, programmed Voyager to execute a basic survey of Neptune should something prevent the final near-encounter transfer of commands. Only at the most frenetic moments, when every fragment of memory space was needed, was the backup mission load removed.197
What remained was to test the system under simulated conditions. JPL and NASA had learned a hard lesson at Uranus. They could not scatter staff across other projects, or even lay them off, and then expect an instant return to service, nor could they expect that upgrades in hardware, software, or operating procedures could synchronize without practice. Beginning in October 1987, nearly all project teams underwent “operational readiness tests” to “validate and calibrate” the DSN and prepare for occultation experiments. The Voyagers themselves experienced special “capability demonstration tests,” with Voyager 1 serving as a “test-bed.” Between 1988 and early 1989 both spacecraft and those communicating with them confirmed protocols and calibrations, one involving a roll-turn course correction maneuver. In May 1989 the entire operation undertook a dress rehearsal.198
THE LONG TREK
From near-encounter at Uranus to near-encounter at Neptune, some forty-two months passed. It had taken the spacecraft twenty-three months to reach Jupiter, another twenty-three months to reach Saturn, and a whopping fifty-three additional months to reach Uranus. Neptune was almost as far from Uranus as Uranus was from Saturn, but the additional velocity Voyager had acquired from its sling-fling around Uranus had hastened its travel. From Earth to Neptune, however, had taken almost exactly a hundred and forty-four months, or twelve years. The Grand Tour was a notably Long Tour.
Interplanetary space is in many respects a benign environment for a machine. Voyager did not experience that long passage as astronauts might: it did not become bored or restless or overcome with anxieties. It shut down most of its instruments, shrank power and hydrazine requirements, and cruised. It entered a mechanical hibernation. Unlike an earthly vessel, it suffered from no physical waves or shearing winds; nor did it have to navigate around unknown shoals. The usual stresses that assault exploring craft were absent. There were no acoustical blasts, no aerodynamic tugs and shears, no gravitational forces pulling it to extinction, no salt to corrode or rain to rot, and no organisms to chew on it. It sailed through no sargasso weeds, acquired no barnacles, endured no ship worms. And it had no human occupants for which it had to sustain an artificial environment. It felt fields and particles, but this was a soft geography, and apart from the planets and asteroid belt, or the rare meteorite, it could sail serenely on autopilot, unworried, and unafflicted by lethargy and ennui.199
But this was not true for its human servants. While Voyager had trekked to Neptune, the United States had experienced four presidential elections and was ten weeks away from a fifth. The Voyager mission had gone through six program managers and was preparing for a seventh. Twelve years was an academic lifetime—two full tenure-review cycles. Staffers had grown up with Voyager. They graduated, married, divorced, had children, transferred and traded jobs, retired, got cancer and injuries, healed, died. Candice Hansen remarked that people “actually remembered when their babies were born relative to encounters.” Ellis Miner noted wryly that the group had been “considerably younger” in 1965, when the Grand Tour was conceived, than in 1989, when it reached Neptune. The long cruise phases were particularly trying for scientists who had to publish constantly to advance careers. Voyager could experience a rhythm of comatose cruising broken by frenzied encounters without a change in life or career. Its human tenders couldn’t.200
While space science seemed a promising career during IGY, in truth it became risky several times over. The spasms of discovery were infrequent and too scattered to sustain regular positions and funding. It always proved easier to create a new project than to continue paying for an old one, more appealing to sponsor a new voyage of discovery than to subsidize the publication of results from returned ones. The missions themselves were too sparse to sustain a self-supporting community. A successful encounter could make its staff into celebrities; but such fame was fleeting, and a failed spacecraft or instrument could be a career-ending blow. Planetary science was a bet against long odds.
Yet the sense that scientific productivity had to accelerate continuously in every field is a recent aberration. In the past, exploration had often taken years, and its scholarly write-up could consume decades. Charles-Marie de la Condamine spent ten years measuring in the Andes before returning down the Amazon; the last member of his expedition did not return to France for thirty-eight years. Alexander von Humboldt devoted his young manhood to preparing for an exploring expedition, spent five years in the field, exhausted five decades and his inheritance distilling it into his fifty-four-volume Voyage to the Equinoctial Regions, and died still writing his popular summary, Cosmos. The Institut d’Egypte, the corps of 151 savants whom Napoleon assembled to survey his conquests along the Nile and who, in the words of Gaspard Monge, would “carry the torch of enlightenment” in its mission civilisatrice, lost 31 members directly, a disaster that distorted the scientific establishment of France for decades afterward; the record of their findings, The Description of Egypt, took its members twenty-six years to complete. The U.S. Exploring Expedition—America’s belated answer to Cook’s voyages—soaked up ten years from first approval to actual departure, spent some four years at sea, and for nineteen subsequent years crawled toward the publication of nineteen volumes (out of twenty-eight originally conceived). By the time the expedition’s findings got into print, the public had more or less forgotten about it, and the country was headed into ci
vil war. Lewis and Clark had taken two years to cross North America, and never did see their vaunted journals published. Beginning in 1867 the Russian general and geographer Nikolai Przhevalsky conducted five major expeditions in Asia with the ultimate ambition of reaching Lhasa. Eighteen years later, he died suddenly while in the field, Lhasa still a mirage over the mountains.201
A successful expedition could not only make a career, it could be a career.
For oceangoing expeditions, long voyages with short encounters were the norm. Still, few could rival the saga of Vitus Bering and the discovery of Alaska.
The motive began with Peter the Great’s 1724 order to Bering, a Dane in his service, to determine whether the far eastern lands of Russia’s expanded empire met the western extent of North America. It took Bering four years to travel to Kamchatka, build a vessel, and sail to the straits that now bear his name. Dense fog prevented a direct sighting, but the nature of the strait and its currents strongly suggested that the two continents were not joined, and native Chukchis confirmed that fact. When he returned, Peter had died, and his successors decided that Bering had not fully answered the question, so in 1731 they sent him back, this time with the naturalist Georg Steller. He finally sailed in the spring of 1741 with two vessels, again constructed in Kamchatka, the St. Peter and the St. Paul. In July 1741 the St. Peter sighted the southern shore of Alaska (at Mount St. Elias), made landfall at Kayak Island, and subsequently wrecked off the coast of Kamchatka, where its crew spent a wretched winter at Fox Island and where Bering died in December. In August 1742 the survivors reached Petropavlovsk and began the long trek across Asia to report their findings.202
The second expedition had lasted over ten years and granted Steller a scientific “encounter” with North America, at Kayak Island, for something like ten hours. The rhythm was eerily like that of planetary exploration. The difference was the immense tedium, frustrations, and suffering that Steller and crews endured to earn those frenzied few hours ashore.
Perhaps the closest historic analogue is the fabled HMS Challenger expedition of 1872-76, generally recognized as the origin of modern oceanography and a model that anticipates Third Age conditions as La Condamine’s did the Second Age.
The Challenger’s complex voyage around the world lasted forty-two months, exactly the length of Voyager 2’s traverse from Uranus to Neptune. The essential rhythm was one of long hiatuses broken by spasms of encounters with islands or ports. In many respects the cadence was also a foretaste of what Antarctic discovery would be like, as explorers broke through the barrier ice at the end of the austral summer, and then wintered over under confined conditions until spring allowed for sledging forays. This was of course equally the pulse of interplanetary exploration. What made it tolerable was the presence of a large cohort of like-minded comrades, and the anticipation of adventure with exotic peoples or unknown lands. Even with other cultures and strange ports of call, this is a formula for a robot. Without the prospect of those interludes, it is hard to imagine how an expedition could thrive.
Of the Challenger ’s crew of 243, a quarter deserted out of boredom, numbed by the tedium of sounding and dredging (“drudging,” as the sailors called it), and out of restlessness on the converted (and confining) corvette; 7 men died, and 26 were invalided out of service or left at hospitals. The scientific corps was marginally better. The “great adventure” across 69,000 nautical miles came at the cost of an “industrious boredom” that nearly drove even the most zealous mad. After they disembarked, the vast tedium continued as some 50 volumes, involving 100 scientists, saw print over the subsequent 20 years, concluding in 1895. Interestingly, as with so many proposals for manned space exploration, the scientific quest involved a search for life in forlorn niches; and this the Challenger found. But so long was the ordeal, and so complex its production, that the public and treasury lost interest, and by the time the Challenger expedition formally completed its task, general enthusiasms were poised to explore new lands.203
Still, the enterprise loomed large in its day—everyone recognized it as a vast and important undertaking, even if it could rouse only sparse popular excitement. It has remained a landmark, a historical point of reference for exploring expeditions much as Tenerife remains a geographic one. The last of the lunar modules (Apollo 17) bore its name as did the first of the space shuttle disasters, and the most successful of the deep-drilling oceanographic research vessels. Yet it has endured perhaps better as an ideal than as a practical guide. In the 1870s there was no alternative to crewed ships and their onboard “scientifics” and “philosophers.” By the 1970s, when the RV Glomar Challenger was coring deep-ocean sediments, there was.
Among the Challenger’s lessons was the difficulty of sustaining research once the adventure ended. The fact is, science is long, politics short, and public interest capricious. The insistence by the “scientifics” that the expedition meant only research, and that research had to be thorough and be published according to the standards of the guild, meant that the drain on the public treasury was bound to be bottomless. Politics and public interest, however, had their own cadences.
In the past, as often as not, scientific societies or wealthy patrons had to intervene to complete the task, which could easily absorb the careers of those involved. Accounts of adventure in the guise of personal narratives were popular and could be published by subscription. The latter often helped underwrite private exploring expeditions in ways that shelves of dense reports could not. Politicians, publicists, and even sciences moved on. Where cruises lasted for years without tangible consequences, where investments were swallowed in upgrading instruments and improving staff performances for brief encounters, it was difficult to sustain much fervor.
Two years after Voyager launched, five months after encounter with Jupiter, the first Star Trek movie was released. It posits a later, fictional, Voyager mission that disappears into a black hole, finds a machine civilization, and then returns laden with knowledge it seeks to transmit to its “creator.” Ten years later, after Voyager 2 had encountered Neptune, the fifth movie in the series, The Final Frontier , opened with a bored Klingon commander blasting a dead-metal NASA spacecraft, now dismissed as “space junk,” for target practice. The tempo of modern society had quickened, and public expectations seemed to shorten. Even as the Galileo mission to Jupiter at last launched, after a decade during which Voyager was the only exploring vessel in action, there was only so much passion that a nominally spacefaring society could muster.204
Many staffers considered the Voyager mission the adventure of a lifetime. For anyone present from its conception—and they were more than a handful—the mission was a lifetime.
THIS NEW OCEAN
The character of the Earth’s oceans set the tempo for the HMS Challenger ’s cruise, and the properties of what partisans eagerly called “this new ocean” of interplanetary space set those for Voyager. In the Third Age, however, the densest discoveries came not from the analogous ocean of the solar system but from the true new ocean of Earth’s abysses.
The deep oceans and interplanetary space were the two commanding realms of the Third Age, and their exploration proceeded in an eerie fugue. Bathyspheres were the high-altitude balloons of the sea; the bathyscaphe Trieste descending to the Challenger Deep in 1960 was the wet twin to Mariner 2 flying past Venus. The knowledge of the Laurentian Abyss was no better than that of the crater Daedalus on the far side of the Moon. There was putative bullion in the abyssal plains. There were schemes for undersea tourism and colonization. There was even precedent in science fiction; after all, Jules Verne had written 20,000 Leagues Under the Sea as well as From the Earth to the Moon. The cold war rivalry played out beneath the waves as fully as it did beyond the clouds.
Yet a profound paradox emerged. Space captured the public and political imagination; the deep oceans did not. Space had a mystique that the abyss lacked. Arthur C. Clarke’s sea novels sank; his space fiction soared. Much of what happened in the seas occurred
in bureaucratically secret “black” programs, not publicly promoted and not known until the cold war ended and declassification began revealing what had happened and the technologies of submersibles and robotic probes became generally available. The high ground for military rivalry was not thermonuclear bombs in orbit but nuclear-armed submarines. The search for life that drove the post-Apollo planetary program, particularly to Mars, found nothing, and might discover it only at immense cost and in token fossils. The exploration of the oceans discovered startling realms of previously unknown life, from the largest ecosystems on Earth to exotic niches powered by chemical rather than photosynthetic metabolism. Likewise, the long-anticipated revolution in geosciences came not from other planets but from Earth’s oceans, as remote sensing unveiled world-girdling mountains, faults, and seamounts. The submersible Alvin visiting black smokers in the East Pacific Rise (the same year Voyager launched) and plucking rocks from the Mid-Atlantic Rift provoked more change than Moon rocks brought back by Apollo astronauts. In his critique of the Apollo program, The Moon-dog gle, Amitai Etzioni shrewdly contrasted the panicked response to Sputnik with the overlooked prospects for the oceans. The paradox was that while attention looked up, the bigger payoff came from below. The promises of the Third Age were unfolding less in the depths of space than in the depths of the Earth’s seas.
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