Voyager: Exploration, Space, and the Third Great Age of Discovery

by Stephen J. Pyne

  INTO THE ABYSS: MODERNISM EXPLORES

  Then it happened again. New lands became available; new technologies and ideas made them enticing; and rivalries between institutions, companies, nations, and personalities mixed combustibly.

  Of a sudden, unexpected realms had appeared. Places previously off-limits because of hostile environs, rivals of comparable power, technological feebleness, or ignorance or timidity had opened up. These were the ice sheets (and sub-ice terrains) of Greenland and especially Antarctica, the deep oceans with their abyssal plains and immense trenches, and of course a solar system, full of worlds that beckoned beyond the vision of earthbound observatories. As powerful instruments and remote-sensing technologies emerged, as manned vehicles and unmanned probes plummeted to the depths and beyond the atmosphere, the prospects for a revival of exploration became possible. Suddenly, a Pacific Ocean that had seemingly yielded its last island to discovery a century before revealed hundreds of new islands in the form of submerged seamounts.

  Antarctica was the transition. It was an abiotic landscape not much accessible to Enlightenment art and science, with no prospects for colonizing settlement, the last of the continental frontiers and the one where the Second Age exhausted itself. Twice before—in 1882 and 1932—a global science had rallied for “polar years.” The earlier versions had focused heavily on the Arctic; this time, after a half century of world wars, proponents hoped to concentrate on the Antarctic.

  The scheme soon snowballed into a call for a more general eighteen-month scientific scan of the Earth, what became known as the International Geophysical Year (1957-1958). The roster of participants was a veritable United Nations of science—some sixty-eight nations in all. It was here, for the first time, that the contours of a new age of discovery came together. IGY’s explorers would visit places inimical not only to humans but to life itself. They would rely on remote-sensing instruments, tracked vehicles, rockets, and robots. They would inventory a planet whole, of which Earth would be the prototype: the home planet became, intellectually, a new world, the first of a dawning age of discovery that would propagate to the fringe of the solar winds. The voyages that followed to planets such as Venus, Jupiter, and Neptune would carry essentially the same instruments and ask the same questions of them as IGY did for Earth.

  Through the infrastructure provided by IGY, noted J. Tuzo Wilson, the “science of the solid earth” was “absorbed into the broader framework of a new planetary science.” Yet Earth’s fluids interested the founders as much as its solids. They peered with special fascination into the upper atmosphere—geophysics, after all, was embedded in the project’s very name. Auroras in particular had pointed to Antarctica as an insufficiently exploited platform for earthly observation, which was where a third polar year had been headed. But the fast-morphing capabilities of rocketry made it possible to send instruments directly into the auroral belts. Both the United States and the Soviet Union had long-extant, if semi-dormant, plans to launch instrumented missiles beyond the realm of high-altitude balloons, leaving rockets as a new means to ask inherited questions. 52

  IGY escalated those scientific yearnings into a political probability. It did for the Third Age what the voyages of Columbus and da Gama did for the First, and the transits of Venus did for the Second. But where the successors to the transits belonged with Enlightenment and empire, the successors to IGY looked, however uneasily, to a Greater Modernism and a postcolonial age. The character of exploration morphed, for IGY did not simply revive the Second Age but assembled the pieces for a Third. The International Geophysical Year was barely three months along when, under its auspices, the Soviet Union launched Sputnik 1. Twenty years after Sputnik leaped into earthly orbit, the Voyagers were flying toward a rendezvous with the moons of Neptune.

  Still, dazzling technologies and an invigorated curiosity are not enough to spontaneously combust into an era of exploration: cultural engagement also demands a sharp rivalry. Those competitive energies flourished with the cold war.

  In retrospect, the great game between the United States and the Soviet Union lasted far less than those between Spain and Portugal, or Britain and France, but the era is young, and if it does in fact mark a Third Age, some other competitors, keen to secure national advantage or prestige through sponsored discovery, may emerge. Without the cold war, however, there would have been scant incentive to erect bases on the Antarctic ice, scour the oceans for submerged mountain ranges and trenches, or launch spacecraft. Two geopolitical rivals, both with active exploring traditions, chose to divert some of their contest away from battlefields and onto untrodden landscapes. The cold war was the final propulsion module that boosted planetary exploration out of Earth orbit.

  Most observers assumed that technology drove discovery. Surely without rockets and remote-sensing devices, the age could not have unfurled. But inventions followed ideas. The pioneering rocketeers had envisioned migrations off Earth and experimented with rocketry as a technological means to move their enthusiasm into space. Nor was the apparatus of the Enlightenment designed to cope with the realms of the Third Age. It broke down on ice, abyss, and space as it did with atoms, relativistic quasars, and self-referential logic. The Second Age had neither the technology nor the software to plunge into those uninhabitable domains; but the intellectual revolution that we might lump together as Modernism could. The most successful explorers of the Third Age would be modernists, whether they willed it or not.

  Yet there was a paradox in its pith. Modernism could deal with such realms, but most modernists lacked the incentive to do so. Outside the sciences they were more inclined to look inward than outward. The culture’s software lagged behind its hardware. The ability to voyage anew appeared before the capacity arose among elites to wish to do it. Pragmatism was a philosophy suited for pioneering; existentialism was not. Those sciences that were most moribund were precisely those most closely bound with the Second Age. Geology was seemingly done more in libraries than in the field; certainly personalities such as Wilson, so despairing of earth science, hoped IGY would spark a reformation. A new era of exploration might ignite, as it had in the eighteenth century, a paradigm shift. (Interestingly, the anticipated revolution occurred exactly between the dates of the two editions of Thomas Kuhn’s The Structure of Scientific Revolutions, 1962 and 1970, which introduced the concept of scientific paradigms, and thus furnished a kind of manifesto.)53

  What bridged the gap, meanwhile, was popular culture. Exploration did not wither away, because the culture had not only institutionalized but also internalized discovery. This was a civilization that could hardly imagine itself as other than exploring. Accordingly, it forged new institutions, of which the International Geophysical Year is an apt annunciation; and with spacecraft dispatched across the solar system, it recapitulated the entire half-millennium saga of Western exploration. Those vessels crossed what enthusiasts were pleased to call “this new ocean,” and in the outer planets they discovered new worlds, miniature solar systems, full of unknown seas and isles. Out of that encounter came a reformed earth science and a comparative planetary science.

  In the Voyager mission, the Third Age stripped exploration down to its essentials. The twin spacecraft went into Earth orbit atop a long heritage of experience and expectation, but they had their own boosters as well, and they used them to point outward and fire into a distinctive trajectory that traced what may well be the age’s most spectacular and defining gesture. If the Voyagers departed Earth full of inertia from the past, they also added a momentum of their own that sent them into the future. They looked back even as they looked beyond. Their trajectory was a constant triangulation of both.

  4. Voyager

  Exploration has always been something done by explorers. Of course they used the technology of their times. They traveled by ships, wagons, rail, balloons, and bathyspheres; they relied on astrolabes, compasses, barometers, and sextants. But it was the person of the explorer, or of an exploring corps, that propelled the
expedition, did the necessary tasks, and embodied its purpose. To invoke the name of the explorer was to evoke the mission overall.

  The Voyagers challenged this traditional formulation. They were robots: the technology was the exploring agent. They were something more than dumb machines, because they had a degree of autonomy and had to act, within limits, independently of their handlers. They were more than simple ganglia of instruments, because they carried their own motive power, which granted them the means to journey. Like any artifact of human contrivance, they exhibited a style that embodied the imagination and values of their creators, which granted them a simulacrum of personality. They could be anthropomorphized in ways that the Santa Maria or the HMS Resolution could not, yet they were far from human, or even alive. In sailing beyond the realm of previous exploration, they also journeyed beyond the realm of expectation about how discovery might be done and what constituted an explorer.

  VOYAGER AS SPACECRAFT

  Like its mission, the Voyager spacecraft was an alloy of ambition and practice, a compromise between the high-end hopes of TOPS and the low-end practicality of the Pioneers that in the end left them as a modified Mariner. The Voyagers were large for their time, built around a hexagonal bus that could be modified to suit particular packets of instrumentation and propulsion. With their ultimate dimensions set by Titan/Centaur, they nonetheless boosted the Mariner frame into another weight class, like a caravel reworked into a small carrack.

  Each spacecraft weighed 1,817 pounds, of which 232 pounds were its scientific payload. There were eleven instruments in all: cosmic ray and plasma detectors, narrow- and wide-angle imaging cameras, ultraviolet and infrared spectrometers, a photopolarimeter, a radiometer, high- and low-field magnetometers, a low-energy charged-particle detector, and antennas for planetary radio astronomy and plasma waves. Bolted against the bus frame was the vessel’s most distinctive visual feature, a high-gain dish antenna. Bristling outward were booms to hold assorted instruments, two antennas, the low-field magnetometer, and the spacecraft’s nuclear power source, a radioisotope thermoelectric generator. (The RTG meant Voyager lacked perhaps the most distinctive visual feature of Mariner: its fan of solar panels.) Adding to its weight were sixteen hydrazine thrusters, a suite of onboard computers, and a propulsion module. Reflective blankets wrapped those portions that required some temperature regulation. The core spacecraft was twelve feet high (the diameter of the high-gain dish antenna), but with its booms fully extended, its width swelled to fifty-seven feet, to its which the propulsion module added another nine. With its reach spanning three dimensions, Voyager claimed an impressive volume.54

  They were larger than most American spacecraft and smaller than Soviet counterparts. Pioneers 10 and 11, which also had to fit into Centaur, were more compact, with a 9-foot main antenna, booms that reached out 10 feet, and a total weight of 570 pounds. They had shed weight by eliminating the onboard computer; by shrinking the size of the antennas, since communication would not have to extend to the outer planets; and by having the spacecraft spin, making it a gyroscope, rather than stabilizing it by multiple thrusters, as Voyager did.Soviet spacecraftwere larger and more ponderous, since heavy-lift rockets were the norm and, from the onset, the Soviet space community intended to send people. At least at JPL, Americans were content with robots, and could miniaturize electronic prostheses, and in any event, granted the reality of their lighter-lift launch vehicles, they had to accept the smaller machines. 55

  The Voyager spacecraft was within the range of smaller exploring vessels. A nineteenth-century keelboat of the type used by Lewis and Clark and later by exploring fur trappers on the Missouri River, had a length of fifteen feet and a width of ten, comparable to Voyager in its Centaur shroud. Columbus’s Niña, his favorite, which he used on his second voyage as well, was a caravel approximately fifty-five to sixty-seven feet long and twenty-one feet wide. The unfurled Voyager, including masts and booms, might claim a rudely comparable volume. For his imaging during the Great Surveys of the American West, relying on glass-plate photography, Timothy O’Sullivan required a small boat on the river and a mule-drawn covered wagon overland. Both vehicles were smaller than the cocooned Voyager. 56

  More interesting is the comparative scientific punch. The Great Voyages had almost none, save the captain’s log and charts, and the overland entradas such as Coronado’s or De Soto’s left nothing more than letters and the occasional journal. The Second Age had science as a prominent purpose, but still could allocate only a fraction of space to its practice. Captain Cook’s HMS Endeavour was exceptional in its commitment to the “scientifics” (not least because Joseph Banks paid for them), but they were five out of a crew of ninety-seven, and commanded a similar fraction of the working vessel, even allowing for use of the “great cabin.” Charles Darwin shared a small room aft on the HMS Beagle, in which hammock, table, instruments, chest of drawers, and shelves constituted his residence, laboratory, and library; probably less than 2 percent of the available floor space of the ship. Where the science ratio was high, it was because the treks were short and did not require transport and sustenance over long distances. John Wesley Powell took three specially constructed dories and a pilot boat, nine men (none of them scientists), and a handful of instruments (sextant, compass, barometer) on his descent through the gorges of the Colorado River; science weighed literally less than his ration of beans. G. K. Gilbert took four men (one of them an assistant) and a complement of mules to the Henry Mountains, the last mountain range to be explored in the United States. Of the 138 species of goods carried, from machine oil and postcards to salt and rice, 41 (30 percent) had some direct bearing on doing science, though they composed probably less than 5 percent by weight; to this, one should add the mules, packs, blankets, and saddles, all of which reduced the scientific load to little more than a backpack. Even a dedicated vessel like the converted steam corvette HMS Challenger, surveying the world’s oceans for over four years and 127,500 kilometers, with 15 of its 17 guns and spare spars removed, had only a scintilla of its space allotted to laboratories. Of three decks and the hold, scientific work claimed perhaps 2 percent, with an equivalent amount devoted to quarters for its practitioners. The reason of course is that most of the enterprise went to caring for the crew, and the larger the crew, the larger the proportion of space and time committed to their sustenance.57

  The space program has investments both greater and lesser. For crewed vessels, the fraction is minimal. Apollo 11 carried small tools and returned 21.7 kilograms of moon rock. Of the twelve astronauts the Apollo program put on the Moon, only one, Harrison Schmitt, was a formal scientist. The reason for the consistently low proportion devoted to inquiry, not only in space but over the long arc of exploration, is of course that the transporting vessel must support not only itself but people, and can do so only by establishing an artificial habitat. It’s as though Mariner 4 or Pioneer 11 had to launch encased in the assembly labs at JPL or Ames.

  Robotic spacecraft could manage a far higher ratio of science to bulk. Of Voyager’s total weight, 1,817 pounds, some 232 (almost 13 percent) came directly from scientific instruments, and a goodly fraction of the rest came from the thrusters and antennas required to position those instruments, not to transport or sustain the spacecraft overall. It was a powered high-tech lab. It needed to carry no flour or salt, no water, no rum, no saddles or pack frames; it housed no mess, no kitchen, no bunks, no dispensary; it held neither library nor ballast. And not least, the spacecraft carried no weapons. It had no armaments: no cannon, shot, or powder. It had shields to protect against micrometeorites and radiation and reflective wrapping to ward off sunlight, but no thick-beamed oaken sides to slow shot. Vacuum had its own peculiar hazards, but they were not such that an onboard arquebus or a guard of marines were needed to repel them. 58

  The chief check on Voyager’s size was the properties of the launch vehicle—the thrust of the Titan rocket and the dimensions of the Centaur shroud. Once in space it would be wei
ghtless, in need only of internal power for electricity and thrusters. It was exploration stripped to its essences.

  Actual fabrication started in 1975. Since each spacecraft was custom-built, testing was continual, and since not all hazards were known, engineers had to work without the prospects for repairs. That required close attention, constant testing, and redundancy.

  Each NASA lab had its own protocols to validate design and parts. For JPL, since the early days of Ranger, this had meant running individual components through trials before assembly, then constructing a mock-up model to test the system’s mechanical features, a thermal control model to verify its ability to withstand interplanetary space, notably heat and vacuum, and finally a proof test model that replicated the spacecraft as fully as possible. The standards were severe, not only because of the known hazards but also because of the uncertainties. Whether or not Voyager went on to Uranus, it was expected that a subsequent vehicle based on its pattern would, so the spacecraft had to survive the equivalent of several mechanical lifetimes beyond what had been attempted.59

  The remaining hazards resided within the spacecraft and were inherent to long treks through interplanetary space. Even robots needed protection, and space-sensing instruments, a habitat. Their demands might command far less space and shielding than those for humans, but they required shelter surrogates nonetheless. To survive extremes of heating and cooling, the spacecraft needed some shielding; and to survive the gusts of Jovian (and other) radiation, it needed hardened electronics, just as vessels in tropical seas were sheathed with copper, or oaken vessels in polar seas strengthened against ice. For the rest it would have to depend on high-reliability components and redundancy. It could not return to have a faulty boom replaced or a hydrazine-powered thruster cleaned, as the vessels of the Great Voyages could replace a broken rudder or a torn sail. It could not replace scurvied or dead crew with new recruits.60