Voyager - Exploration, Space, And The Third Great Age Of Discovery
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There were a few snafus. A glitch at the Canberra DSN station lost some data, but engineers were able to have Voyager replay the stored information later. There were other minor “deviations” in expected performance. But for what Ellis Miner called JPL’s “aging brainchild,” they were “few in number and minor in consequences.” Voyager had far exceeded its basic design parameters; it had twisted, measured, imaged, rolled, and reoriented its way around probably the most anomalous planet in the solar system; it had gone where no spacecraft had gone before; and when it hurtled past the far side of the Uranian system, it was on a dead course for Neptune, some thirty times farther from the Sun than Earth is, a trek that even with its once-more gravity-assisted acceleration would require 3.5 years.163
Uranus was a new world. It lay almost beyond the reach of Earth-based observation. No prior space probe had visited it, and only its most coarse contours had been traced. After Voyager, Uranus became, if not familiar, at least recognizable.
Every instrument of Voyager, and even the gravitational behavior of the spacecraft itself, added real knowledge: The mass of Uranus, and its aspherical distribution; the period of planetary rotation; the structure and chemistry of the atmosphere, including an abundance of helium, water, and methane, and their stratification; the eccentric energy budget, its reflectivity and reradiation, a pattern that leaves the planet much warmer than solar heating alone would permit; a unique meteorology, driven more by planetary rotation than solar radiation, with subtle differences in color and haze; an accurate geometry of the Uranian magnetosphere, including the wide divergence between magnetic and rotational poles; the confirmation of polar aurorae and lightning; radio emissions only weakly controlled by solar winds; low-density plasma filling out the magnetosphere; new rings and ring arcs—their composition, obscure reflectivity, particle size, dynamics. If images were “moderately disappointing,” as one observer noted, that had to do with Uranus’s hazy outer atmosphere, which blurred the kind of structure that riveted attention at Jupiter and even Saturn, and with the baffling darkness of its hard geography of orbiting particles.164
Perhaps most spectacularly for both the public and even jaded scientists, Voyager 2 found miniature new worlds: it tripled the number of known Uranian moons. Because its passage through the system was so swift, its imaging hardware could not be adequately reprogrammed to photograph them all, nor because of its oblique rush through the orbital plane could its cameras view the outermost moons with the kind of resolution it had brought to the Jovian and Saturnian satellites; and to be authenticated, each revelation required at least two separate sightings, with enough lag to calculate a probable orbit.
But they came in a rush of near-epiphany. The first moon was found on December 30, 1985, sufficiently early that it could be targeted in the final flurry, sandwiched amid images of Miranda. Two more were identified on January 3; one on January 9 and another on January 13; another three on January 18; two shepherd satellites, flanking the epsilon ring, on January 20; and the last on January 21. Since its known moons had names from Shakespeare’s A Midsummer Night’s Dream, the first new discovery became Puck, and the others derived from various Shakespeare plays or from Alexander Pope’s The Rape of the Lock. All this new discovery, moreover, happened while the five known moons were also imaged, with varying degrees of resolution, and their properties compared. The five outer moons were brighter, showed evidence of former melting, and were colder. The two most intriguing were also those with the highest resolutions. Ariel was lightly cratered, which revealed a period of post-bombardment surface flooding, or “cryovolcanic flows.” Miranda was, simply, a jumbled mess, or more formally, a “geologic enigma.” It seemed as though it had smashed apart, then cold-fused with whatever had splintered it, and there stayed, like a geologic Frankenstein’s monster, full of odd lithic parts and thick stitches. Three days after its last discovered satellite, Belinda, Voyager slingshotted through near-encounter.165
Even to those experienced in Voyager’s serial surprises, the capacity of the valiant spacecraft to amaze remained undiminished. However dark Uranus, Voyager 2 had shone.
On January 26, near-encounter segued into post-encounter. The Voyager team scheduled a final press conference for 8:00 a.m. on January 28, 1986, what everyone anticipated would be the celebration of a weary, wondrous quest. Instead, thirty-five minutes later, participants watched in horror as the space shuttle Challenger exploded on launch. The Uranus encounter could survive radiation, celestial mechanics, sagging power, balky actuators, particle attacks, impossibly tenuous lines of communication. It could not compete with immolated astronauts.
BREAKUP
For almost thirty years the competing factions within the American space program had united in common cause under a fulsome NASA budget and against a cold war rival. At the onset of the space race their primary contestants, symbolized by JPL’s William Pickering, the University of Iowa’s James Van Allen, and the U.S. Army’s rocketeer Wernher von Braun, had hoisted Explorer 1 over their collective heads, and they had continued that display of public unity, if not amity, as a downsizing Apollo program and its shuttle successor cleaved the funds that kept them all in loose alliance and forced the contestants to fight for the scraps that fell from the shuttle’s table.
Both NASA and space apologists wanted to isolate criticisms within the community lest any harping harm the space enterprise overall. The official line was that both programs were necessary, and that what was good for one was good for the other. NASA tried to quarantine the issue by segregating the manned and unmanned programs except at the highest administrative level. But as the competition sharpened over the years, von Braun’s vision of space colonization came to dominate; Van Allen’s perspective of space as a scene for science suffered, and over the years Van Allen became more vocal, expounding his criticisms to fellow space scientists, to the public and press, and to Congress. The competition was both undeniable and subtle: the sheer weight of the manned space program could shove rivals aside. During Pioneer 10’s encounter with Jupiter, von Braun had shown up at mission control and sat on a desk stuffed with terminals to watch the show. His rump hit a switch on a video terminal and turned it off, and since all the terminals were linked, the entire system crashed. The mission staff had to remove him and reboot. That episode might well stand (or sit) as symbolic of the larger rivalry.166
By the time Voyager 2 reached Uranus, it was obvious that NASA’s three-ply composite was delaminating. The agency had consistently favored the manned over the unmanned, the aeronautical industry over the universities and research centers, and defense over science. The manned program, with its ultimate vision of extraterrestrial colonization, might fume over the slow pace of the shuttle’s development and express frustration with the lack of progress toward Mars, but the shuttle, Skylab, and the space station were at least within its informing narrative. That program, and its increasing domination by the Pentagon, cut the others off in midsentence. But while the immediate aftermath of the tragedy hushed any overt criticism—one could only voice admiration for the dead astronauts and mouth determination to honor them by reflying the shuttle—the options were out in the open.
In the January issue of Scientific American, which ran a few weeks before the disaster, Van Allen had publicly broken ranks and questioned the value of the manned program altogether. In May he wrote an essay for Science in which he systematically compared the manned and unmanned programs, noting that “many space enthusiasts blithely ignore the fact that almost all the truly important utilitarian and scientific achievements of our space program have been made by instrumented, unmanned spacecraft.” He mocked the “mistyeyed concept that the manifest destiny of man is to live and work in space”; scorned the “Columbus analogy” to support a manned mission to Mars as “massively deceitful”; and concluded with a “poignant juxtaposition” of the Challenger disaster and Voyager 2’s flyby of Uranus. (Some years later he suggested, with tongue only partly in cheek, that NASA sell the
manned space program to China.) Instead of pursuing mirages, NASA ought to develop “space applications of widespread human importance” and sponsor “major advances in human understanding” of the universe. It ought, in brief, to be a scientific research institution.167
It was obvious that robots were not only cheaper and safer than people, but also capable of increasingly sophisticated semiautonomous behavior, and were improving at far faster rates than Homo. If NASA had committed itself to robotic spacecraft, he implied, there would have been no space shuttle to drain away funding from the truly breakthrough programs and no Challenger to explode. The science fiction that seemed to animate his rivals pointed not to a usable future but to a visionary past.
Neither Van Allen nor von Braun affected Voyager directly. Van Allen, to his and others’ surprise, failed to make the scientific cut and had no instrument to place on either Voyager’s boom; and von Braun died two months before Voyager 2 launched. But his ghost continued to haunt NASA and hound Voyager.
As the costs of Apollo ballooned, NASA had dumped the original Voyager mission to Mars. The reincarnation of Apollo as the space shuttle in 1972 repeated that experience and soon whittled the original Grand Tour down to MJS 77. In July 1979, as Voyager 2 commenced its encounter with Jupiter, it had to compete for media attention with the death spiral of Skylab and speculation about where it might land (and on whom) and with Tom Wolfe’s paean to the Mercury astronauts, The Right Stuff.
Then, as Voyager 2 approached Uranus, JPL realized that the proposed shuttle manifest included a launch four days before near-encounter. Such a schedule conflict could affect support and tracking, to say nothing of public attention, and JPL asked to have the shuttle delayed. Voyager 2 had spent 8.5 years getting to Uranus; the shuttle could wait 8.5 days. The request went to James Beggs, then NASA director, who denied the request. When asked why, he reportedly replied, “The White House doesn’t want the launch slipped.” The Reagan administration had long sought to hobble the planetary program; this final snub, however petty and unreasonable, was in keeping. As it happened, the launch schedule for the shuttle Challenger slipped anyway, until after Voyager 2’s near-encounter. It then launched under questionable circumstances and promptly blew up.168
The immediate reaction at JPL and among Voyager enthusiasts was shock, and grief for their mutual enterprise of space travel. There was, as Ellis Miner put it, “a spontaneous day of silence for fallen friends and blasted hopes.” But the realization quickly grew that rebuilding the shuttle program would eviscerate the planetary program, not only from financial starvation but from lack of a launch vehicle. The shuttle had taken everything. NASA had put all its eggs into one basket and watched it explode. The Challenger disaster was a “temporary death knell,” Miner continued, for the “continued unmanned exploration of the planets.”169
Others were not so forgiving. “Even then,” as Bruce Murray expressed it, “Fletcher [NASA director] would not acknowledge what everyone else knew—that planetary missions were intrinsically incompatible with the Shuttle.” America’s planetary exploration remained “hostage to the dying embers of NASA’s Shuttle fantasy.” Already, to pay for the shuttle and its endless delays and overruns, the United States had declined to join the international mission to Comet Halley. Now the Galileo mission to Jupiter was postponed indefinitely. Ulysses to Jupiter and the Sun, Magellan to Venus, Cassini to Saturn, the Mars Observer, the Comet Rendezvous/Asteroid Flyby—all went into suspension as NASA struggled to make its white elephant fly again. All that remained was Voyager.170
What is perhaps less obvious is the challenge space science, as pure science, the search for data, posed to Voyager-like missions. This was in some respects more subtle, as Van Allen’s own career demonstrated.
After all, James Van Allen had been a founder of the field. He had blazed a postwar trail to the outer atmosphere with balloons, rocketoons, and rockets; had been part of the catalytic discussions that led to IGY, and had helped ensure its commitment to the geophysics of soft geography; had sent the first instrument aloft on Explorer 1, which had led to the first great discovery of the era’s space science, the eponymous Van Allen radiation belts; and had outfitted the Pioneer spacecraft, including Pioneers 10 and 11, with critical instrumentation. He had grown up with the space program, and grown famous because of it. Yet his emphasis could easily divert attention away from spacecraft and onto other platforms. In particular, astronomers might well—and did—argue for Earth-orbiting telescopes, what became NASA’s Great Observatories.
If science is what you want, they delivered. Within twenty years after the Grand Tour, and after its own blinkered start, the Hubble Space Telescope (HST) and other major observatories could achieve “nearly Voyager-class imaging” of the outer planets. They could crudely map Pluto and its moon Charon; they could offer evidence that the Kuiper Belt, with some two hundred million inert comets, existed; they could improve on the Voyagers’ astonishing tally of discovered satellites. Altogether the Voyagers discovered twenty-six new moons among the outer planets; the HST has since found forty-eight for Jupiter alone, most the size of asteroids. The HST can peer at a planet for long periods, return to detect seasonal and orbital changes, image the same scene over and over, and combine it with sophisticated software to detect satellites and rings. It can be patient. The Voyagers flew past once, faster than the human eye could follow.171
If partisans of manned programs had clawed away at planetary spacecraft, so had space scientists who wanted money and institutional attention lavished on topics of interest to them, and who might well regard robotic spacecraft as a proxy for the pointless adventuring that appalled Van Allen. The most powerful institutional voices on the NAS and NASA space science boards were astronomers, who tended to view planetary science, with its discovery of icy geysers, erupting volcanoes, and whacked-out moons, as a latter-day form of field naturalist gathering the contemporary equivalent of conch shells and orchids, and they consistently undermined the case for spacecraft in favor of telescopes and their equivalents.
Of course some measurements can’t be done from observatories, great or otherwise, just as some activities robots can’t do as well as people. But the pace of technological innovation continues to quicken. Much as robotic exploration was much cheaper than manned, so, potentially, was near-Earth science cheaper than far-trekking spacecraft. The arguments made in favor of robots as scientists can be made equally against robots as instruments.
The Voyagers thus had to fight on two flanks. Was Voyager, as both banks of critics implied, only an interim measure, with the robots destined to succumb either to humans or to instruments? Were such spacecraft only devices to do the work of other programs, or might they have an identity of their own? Did they do what the others could not? How might Voyager answer the charge that the Grand Tour was a Great Detour?
Like all defining expeditions, the Voyager mission was a synthesis—that’s what gave it stamina and cultural power. It differed from orbiting observatories in that it traveled. That’s what made it exploration, not merely extreme science. It was not the gathered data, artifacts, souvenirs, loot, logs, and journals that transformed curiosity into discovery, and discovery into exploration; it was the trek. The medium—the journey—was part of the message. It mattered not solely as a means of positioning instruments but as an event in itself, one that segued into quest. An entrée of geophysics and a dash of astrobiology might be enough for academicians scornful of spacecraft cameras and other seeming popularizations. It was not enough for the culture, which wanted to recreate that alchemical alloy of discovery and adventure, fused into a journey and culminating in an encounter. It wanted the personification of cultural identity, whether it be placed on a Nansen sledge or an adapted Mariner hex, whether by a character-testing Edwardian or a quasi-autonomous robot.
And it is the issue of character and encounter that most separated Voyager from traditional exploration. What it encountered did not require a human presence. At one level
this is simply the argument for better instrumentation. Amid the geographic realms of the Third Age, there is no Other; not as a person, an intelligence, or a biota. People are simply a clever means to record data, which machines can do. The Mercury astronauts worried that they might be nothing more than “Spam in a can,” that monkeys could do (and did do) what was required of a passenger. What, then, exactly, do people bring to the event? They know those hostile environs only through heavily intermediated suits and mechanical cocoons. They cannot smell or taste or touch or hear those scenes. They can only see them. Yet the “eyes of discovery” are available to everyone with access to a TV set or an LCD monitor connected to the Internet. The human “presence” is already mostly a machine presence. Exploration is becoming more and more virtual. As Robert Ballard said of manned submersibles, “ultimately” their “limits will become intolerable.”172