Voyager: The Grand Tour
of Big Science

by Andrew J. Butrica

Of all the NASA missions, none has visited as many planets, rings, and
satellites, nor has provided as many fresh insights into the outer planets,
as Voyager, which was launched in 1977. On 19 May 1981, the National Aeronautic
Association awarded its Collier Trophy to the "Voyager Mission Team, represented
by its chief scientist Dr. Edward C. Stone, for the spectacular flyby of
Saturn and the return of basic new knowledge of the solar system."1
The awarding of the Collier Trophy was a fitting tribute to the science
carried out by the Voyager spacecraft, which also received twice, in 1980
and 1981, respectively, the Dr. Robert H. Goddard Memorial Trophy, an aerospace
industry prize awarded annually since 1958 by the National Space Club to
recognize achievement in astronautics, for the Voyager encounters with
Jupiter and Saturn.2

Neither the Goddard nor the Collier Trophy recognized completely the
science accomplished by Voyager, for after flying by Uranus (1986) and
Neptune (1989), it left the solar system to explore interstellar space
until around 2020, when the spacecraft will lack sufficient power to operate
the scientific instruments on board and to return data to Earth. By then,
the two Voyager spacecraft will have operated longer, and returned data
from greater distances, than any previous probe.

Voyager is planetary exploration on a grand scale. First conceived as
a "Grand Tour" of the solar system from Jupiter to Pluto, then scaled back
to a more modest mission called Mariner Jupiter-Saturn until its incarnation
on the eve of launch as Voyager, the mission has been, and will remain
well into the future, NASA's biggest planetary expedition. The two Voyagers
have explored more planets (four), have discovered more moons (22), and
have returned more photographic images, than any other space flight.3
The original price tag of nearly a billion dollars made it the second most
expensive planetary voyage, exceeded only by Viking, which landed on Mars
in 1976. 4 Each Voyager spacecraft
weighed more than any Surveyor or Ranger sent to the Moon and more than
any Mariner or Pioneer probe (except for Pioneer Venus), though less than
the combined weight of the Viking lander and orbiter.5

Its scientific, budgetary, and technological immensity makes Voyager
archetypical big science. Born of what President Dwight D. Eisenhower called
the military-industrial complex, and what historian Stuart Leslie more
recently has called the military-industrial



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252 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

|Photo montage of Saturn and four moons assembled from images taken by Voyager.                                                                                                                                                                                                                                                                                                                                                
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|The Voyager mission team, represented by Chief Scientist
Dr. Edward C. Stone received the award in 1980, specifically for the spectacular
fly-by of Saturn and the return of basic new knowledge of the solar system.
This photo is a montage of images of the Saturnian system prepared from
an assemblage of images taken by the Voyager spacecraft during its Saturn
encounter in November 1980. (NASA photo no. 80-H-366).

academic complex,6 big science quickly
came to characterize the civilian enterprise to explore space, that is,
what one might call the NASA-industrial-academic complex. Since its creation
in 1958, the National Aeronautics and Space Administration has shaped American
science to an extraordinary degree, namely by providing the financial and
institutional aegis for the transformation of American planetary astronomy
into big science, yet NASA's primary objective was (and whose budgetary
bulk paid for) the designing, building, and launching of vessels for the
exploration of the solar system.

Although the Voyager mission is inescapably an example of NASA big science,
the actual scientific experiments were carried out by scientists employed
by NASA Field Centers or by individual scientists who more appropriately
fit the category of little science. The latter Voyager scientists worked
individually or in small collaborative groups, often with graduate assistants,
in university laboratories with relatively small budgets and limited laboratory
equipment. In the case of Voyager, the management of decision making and
the organization of scientists, just as much as the creation and utilization
of monumental technology and mammoth technological networks, delineated
big science.

Planetary astronomy has had a long existence as simultaneously both
little science (astronomers working individually or in small groups) and
big science (large expensive telescopes and observatories) that dates back
to the sixteenth-century island observatory of Tycho Brahe. The number,
sophistication, and expense of instruments have escalated over



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 253

the centuries, particularly in the past 100 years. The interplanetary
spacecraft has become the new observatory, carrying scientific instruments
on trajectories independent of the Earth's course through space. Planetary
astronomy's very dependence on instrument technology necessarily and inescapably
has driven it in the direction of big science.

The Voyager mission, and NASA planetary missions in general, illustrate
the amphibious life of planetary astronomy as both little science and big
science. The Voyager project transformed geographically-dispersed individual
scientists drawn from a spectrum of scientific disciplines and subdisciplines
into members of a centralized, multidisciplinary big science team. As each
Voyager spacecraft approached one of its target planets, the members of
the mission's scientific teams arrived in Pasadena, the home of the Jet
Propulsion Laboratory, to take up residence for the period of closest approach.
The mission provided those scientists a set of instruments and a spacecraft
observatory. Their role was not limited to using the spacecraft instruments,
however; those scientists also played a critical role in shaping the mission
even before it was funded principally through the Space Science Board and
its summer studies. Conflict between the scientific community and the NASA
Field Centers, in particular, served as the catalyst that brought about
the demise of Voyager's predecessor, Grand Tour. This chapter examines
the role of scientists in the shaping of Voyager before launch and their
transformation into a big science project team through their participation
in the Voyager mission, then considers the critical role of technology
in the conduct and success of that mission's science, as well as the relationship
between big science and little science and the role of technology in that
relationship.

Voyager can be said to have begun in 1965 as Grand Tour, an extensive,
if not grandiose, planetary mission planned in the midst of shrinking NASA
and Federal budgets, at a time when NASA sought to define its mission in
the post-Apollo era. The Apollo lunar program in 1965 was reaching its
funding peak; NASA's annual overall budget declined from $5.2 billion in
1965 to slightly over $3 billion in 1972, 7
in response to social and political pressure on the Federal budget stemming
largely from the Great Society programs and the Vietnam War, as well as
the conservative fiscal policy of the Nixon administration.

In the summer of 1965, in order to define post-Apollo NASA missions,
the National Academy of Sciences' Space Science Board 8 
held a summer study of scientists at Woods Hole, Massachusetts. The scientists
urged NASA to shift interest from the Moon to the planets, giving primary
emphasis to Mars and Venus, more so than to the outer planets. As for the
outer planets, the summer study recommended two directions: either reconnaissance
flyby missions to each of the outer planets or an intensive study of Jupiter
using orbiters and atmospheric entry probes.9
These two exploration strategies dominated discussions of outer planet
exploration over the following years. The 1965 Woods Hole summer study
thus demonstrated that the congeries of scientists who made up the planetary
scientific community already had ideas about how NASA ought to set about
exploring the outer planets.

Most members of the planetary science community preferred smaller, tested
spacecraft flying short missions over large, expensive, complex and lengthy
projects. They feared that the government might cancel their smaller projects
in times of tight budgets in favor of a few expensive high-profile missions.
Moreover, with small inexpensive spacecraft launched at relatively



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254 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

short intervals, scientists could more easily follow up on new discoveries
than they could with one large complicated spacecraft that took many years
of preparation. Major missions to a large degree tended to solidify research
into a specific line of investigation for a long time. 10

Into the gelling consensus that emerged from the Woods Hole study came
the idea for Grand Tour. The Grand Tour would take advantage of a once-every-175-year
planetary alignment to send several spacecraft to all five of the outer
planets, from Jupiter to Pluto. Launch windows were available relatively
soon, between 1976 and 1980.11 Despite
its subsequent reputation as an exorbitant expenditure of public funds,
a pair of Grand Tour spacecraft actually would have been far more economical
than the several individual probes to the outer planets proposed by scientists
at Woods Hole in 1965. Grand Tour could reduce costs further by surveying
the outer planets in less time-in eight to thirteen years, depending on
the trajectory, compared to thirty years for a direct flight to Neptune
alone-by employing a maneuver called gravity assist,12
in which the spacecraft exploited a planet's gravitational field to increase
its velocity and alter its trajectory, thereby reducing both launch power
requirements and flight time.13 Grand
Tour thus was intrinsically a money-saving concept.

Appearing to save money was critical to selling a large-scale project,
even during the days of big NASA budgets, as illustrated by the recollection
of Donald P. Hearth, NASA Planetary Programs Office director, when he learned
about Grand Tour for the first time:14

> You've got to remember selling a new start is a bitch. Even
> then-it's even worse today, but even then. It's almost as hard to sell
> a hundred million dollar project as it is a billion dollar project. And
> a hell of a lot more work to sell two $100-million projects than one $200-million
> project.

Before NASA Headquarters considered Grand Tour, though, the jet
Propulsion Laboratory15 started promoting
it, beginning with a December 1966 article penned by



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 255



|Photo of the surface of Ganymede assembled from multiple Voyager photos.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|This reconstruction of part of the northern hemisphere
of Ganymede was made from pictures taken by Voyager at a range of 313,000
kilometers (194,000 miles). The scene is approximately 1,300 kilometers
(806 miles) across. It shows part of a dark, densely cratered block which
is bound on the south by lighter and less cratered, grooved terrain. The
dark blocks are believed to be the oldest parts of Ganymede's surface.
Numerous craters are visible, many with central Peaks. The large bright
circular features have little relief and are probably the remnants of old,
large craters that have been annealed by flow of the icy nearsurface materials.
The closely spaced arcuate, linear features are probably analogous to similar
features of Ganymede which surround a large impact basin. The linear features
may indicate the former presence of a large impact basin to the southwest.
(NASA photo no. 79-H-393).

Homer Joe Stewart, head of JPL's advanced mission planning. In 1967,
JPL used the project as a lure in its employee recruitment literature.16 
In short, although other NASA Field Centers competed, especially the Ames
Research Center, JPL put forth a tremendous effort to make Grand Tour a
JPL project.

The NASA Office of Space Science and Applications faced the task of
establishing priorities among the various proposed missions to the outer
planets. The agency called on its own scientific community to formulate
outer planet exploration approaches and created the Outer Planets Working
Group in 1969. Its creation was part of a larger agency reorganization
initiated by Homer Newell, NASA associate administrator, in order to focus



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256 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

on the development of long-range plans, as opposed to the emphasis in
preceding years on the budget year or on near-term plans. The reorganization
resulted in the creation of twelve planning panels and six special study
groups covering the gamut of NASA activities, with a Planning Steering
Group chaired and coordinated by Newell himself. 17

The Outer Planets Working Group consisted of two representatives (a
scientist and an advanced mission planner) from each of the NASA Field
Centers interested in Grand Tour and other outer planet missions (JPL,
Ames, Goddard, and Marshall) and from the Illinois Institute of Technology
Research Institute's Astro Sciences Center, a NASA think tank of sorts
which had initiated a Jupiter mission study in the fall of 1968. The Working
Group thus limited the decision-making process to NASA Field Centers that
were vying to design spacecraft; the external scientific community was
not part of that process.

Rather than favoring a single Grand Tour to the outer planets, the Working
Group endorsed the concept of multiplanet flyby missions, preferably two
three-planet voyages (Jupiter-Saturn-Pluto in 1977 and Jupiter-Uranus-Neptune
in 1979), on the grounds that these would reduce the mission time from
thirteen or more years to only seven and a half.18
From June 1969, officials in the NASA Planetary Programs Office began to
associate the phrase "Grand Tour" primarily with a pair of three-planet
missions, rather than the original single tour concept.19

The Outer Planet Working Group also recommended that: "A new Mariner-class
outer planets spacecraft appears adequate for accomplishing the more urgent
scientific objectives."20 Although
NASA ultimately followed that recommendation by building Mariner Jupiter-Saturn,
the space agency did not heed the advice until Grand Tour's demise. One
of the chief activities of the NASA Field Centers was the design and construction
of spacecraft. Not surprisingly, then, the Working Group's advice also
called for the designing and building of a large number of spacecraft.

NASA next put the question of outer planet exploration to the twenty-three
scientists of the Space Science Board summer study that met in June 1969.
Those scientists recommended a specific schedule of five outer planet missions:
one to Jupiter, one to Jupiter and the Sun, one to Jupiter and Uranus,
and the two Grand Tour missions outlined by the Outer Planets Working Group
(Jupiter-Saturn-Pluto in 1977 and Jupiter-Uranus-Neptune in 1979). The
recommendations artfully combined Jupiter-intensive exploration and separate
missions to the transjovian planets, that is, what the scientific community
originally set out at Woods Hole in 1965, with the Grand Tour notion issuing
from NASA's jet Propulsion Laboratory. NASA headquarters planetary programs
officials interpreted the findings of the 1969 summer studies as support
from the scientific community for Grand Tour.21
NASA now intended to request Grand Tour funding for fiscal 1971.

Although the opinions of scientists and NASA Field Center experts had
played the greatest role in shaping outer planet exploration up to this
point, a new, and ultimately more powerful, player took the stage: the
recently elected Nixon administration. The Bureau of Budget under Nixon
consistently reduced NASA's budget allocation. No longer



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 257

|Photo of Jupiters ring was recorded by Voyager 2 on July 10, 1979.                                                                                                                                                                                                                                                                                                                                                                                                                    
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|This view of Jupiters ring was recorded by Voyager
2 on July 10, 1979, at a distance of 1.5 million kilometers (930,000 miles).
The unexpected brightness is probably due to forward scattering of sunlight
by small ring particles. Seen within the inner edge of the brighter ring
is a fainter ring which may extend all the way down to Jupiter's cloud
tops. The existence of the ring was first learned when photographed by
Voyager 1 in March 1979. (NASA photo no. 79-H-507).

was space exploration a tool for competing with the Soviet Union. Nixon
perceived the Apollo program in partisan terms, as a Kennedy program. Thus,
for example, in December 1969, the Nixon administration quickly moved to
shut down the only NASA laboratory ever closed, the Electronics Research
Center in Cambridge, Massachusetts, which Nixon was said to have perceived
as a Kennedy pork project.22

The Nixon budget cuts hit NASA's fiscal 1971 budget, in which the space
agency requested funding for two three-planet "mini" Grand Tours scheduled
for launch in 1977 and 1979. At the same time, NASA faced the cost overruns
of the Viking orbiter and lander, whose dramatically escalating overall
cost was earning Viking the title of NASA's most costly project after Apollo
(rising from $364.1 million in March to $606 million in August 1969). The
Nixon administration cut NASA's budget, which translated into a loss of
$75 million to the $413.9 million budget for NASA's Office of Space Science
and Applications, the budget portion that fed Grand Tour. The "pain" of
NASA's fiscal 1971 budget was not confined to Grand Tour, though, and included
suspending production of Saturn V launch vehicles, stretching out Apollo
lunar missions to six-month intervals, and delaying the launch of Viking
from 1973 to 1975. 23 This first postponement
of Grand Tour thus did not



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258 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

|Illustration shows plan to use Jupiter to accelerate, break, or steer spacecraft by Gravity-Assist.                                            
|-----------------------------------------------------------------------------------------------------------------------------------------------
|"Gravity-Assist Swing-by Aids Many Missions" chart
shows the swing-by as it deflects, accelerates, and decelerates. (NASA
photo no. 69-H-1521).

arise from any perception that the mission was too costly per se, but
from a White House attempt to reduce NASA's, as well as the overall Federal,
budget.

The severe and unprecedented reduction of NASA's Office of Space Science
and Applications budget led Philip Handler, president of the National Academy
of Sciences, to suggest to NASA administrator Thomas Paine in November
1969 that a Space Science Board panel evaluate and rank the disciplines
supported by NASA, such as planetary and lunar exploration, astronomy,
and Earth environmental sciences. Paine agreed. Subsequently, a summer
study, involving nearly ninety scientists, took place at Woods Hole, Massachusetts,
from July 26 to August 15, 1970. In addition, a fourteen-member executive
committee, chaired by Space Science Board member Herbert Friedman of the
Naval Research Laboratory, had the daunting task of combining the proposals
of the working groups into an overall priority system.

What emerged was an ominous schism between the advice of the scientists
of the Woods Hole Planetary Exploration Working Group and that of Friedman's
executive committee. The Working Group urged that Grand Tour not be missed:
it was a unique opportunity. The executive committee, on the other hand,
favored Jupiter-intensive missions. The difference partly arose from concerns
about the technological demands of the two types of missions. Jupiter-intensive
missions required development of spacecraft lasting only five years; the
real design challenge was in the probes, which had to withstand entry into
the Jovian atmosphere. In contrast, while Grand Tour would not be entering
any planetary atmospheres, it demanded spacecraft capable of enduring a
much longer time period. In both



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 259

cases, spacecraft design was intrinsically linked to mission cost. Even
some Grand Tour advocates complained that JPL had not made any effort to
design a more modest spacecraft with an estimated cost that would be more
in line with the prevailing budgetary climate .24

The planetary scientists opposing Grand Tour fell into two camps. One
camp preferred smaller, less costly, and shorter duration missions; the
second feared that support of Grand Tour would divert funds from the building
of a large space telescope. It was at this point that the perception that
Grand Tour's price tag was too high emerged. Friedman led the contingent
of astronomers who advocated building a large space telescope; they successfully
placed the large space telescope in the highest priority category of the
study. Friedman placed a higher priority on a large 45-inch orbiting telescope
than on Grand Tour for reason of both its lower cost and its perceived
higher scientific promise. Already, Grand Tour bore an estimated price
tag of $700 million, and funding it, Friedman and others feared, would
have a serious impact on other highly desirable scientific missions. The
high cost of Grand Tour was being compared to Viking, which had become
so costly that in early December 1969 an ad hoc Viking Review Panel set
up by the Space Science Board almost recommended terminating the project.25
The collision of opposing views among scientists that the Woods Hole summer
study brought to light was to resound throughout the space exploration
community and to have an impact on Grand Tour. By December 1970, members
of the Space Science Board were raising questions about Grand Tour. 26
Elsewhere, in negotiations with the Office of Management and Budget (OMB)
in December 1970, George M. Low, NASA Acting Administrator, suggested replacing
Grand Tour with a mission to Jupiter-Uranus-Neptune in 1979 and a possible
additional mission to jupiter-Saturn-Pluto in 1977 or 1978, but which would
require additional funding. 27

In January 1971, months before the publication of the Friedman report
on March 9, 1971, Friedman's report was leaked to the House Subcommittee
on NASA Oversight, as well as to the Washington press. John Lannan, a reporter
for the Washington Evening Star, made public Friedman's anti-Grand
Tour views, and a Science News article reported the opposing views
of some of the Working Group members. The contention over the funding of
Grand Tour now spilled over from the space and astronomical communities
to the public at large and even beyond the nation's borders.28



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260 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

At the heart of the contention was the JPL Grand Tour spacecraft called
TOPS. Grand Tour consisted of four launches, two to Jupiter-Saturn-Pluto
in 1976 and 1977, and two to Jupiter-UranusNeptune in 1979. NASA estimated
the cost of the four missions to range from $750 to 900 million plus $106
million for launch vehicles.29 One
substantial portion of the cost of Grand Tour was development of a self-test
and repair computer (STAR) that would operate for over ten years at a great
distance from Earth. Another significant portion of the price tag represented
development of the so-called Thermoelectric Outer Planets Spacecraft (TOPS)
by JPL. The long lifetime of the TOPS spacecraft was to be achieved at
the expense of increased vehicle weight and higher cost.30

Grand Tour TOPS and STAR development programs potentially represented
a considerable fountain of paid employment for JPL employees, contractors,
and subcontractors, as well as laboratory overhead, in the post-Apollo
era. Contractor lobbying of the White House and Congress on behalf of the
large space telescope helped to win congressional approval for it. Without
that lobbying, historian Robert W. Smith has argued, Congress would not
have approved funding the telescope.31
But ultimately the bid to develop TOPS reduced potential political support
for Grand Tour's other options.32

Further complicating matters was Senator Clinton P. Anderson (D-NM),
champion of the Los Alamos nuclear weapons laboratories and an enthusiast,
until his retirement in 1973, of the development of a nuclear rocket engine
called NERVA. As chair of both the Senate Aeronautical and Space Sciences
Committee and the joint Atomic Energy Committee, Anderson provided NASA
and the Atomic Energy Commission over $1.4 billion, about $500 million
of which was spent in Los Alamos, for the development of the NERVA engine,
which, Anderson held, was ideally suited for exploration of the outer planets,
as well as for more advanced missions. Anderson worried that NASA and the
OMB were shifting money from NERVA to fund Grand Tour. When the NASA budget
came before Anderson's Aeronautical and Space Sciences Committee on May
12, 1971, his committee voted five to two to reduce Grand Tour's budget,
while an amendment to increase NERVA funding passed. Werner von Braun worried
that ardent congressional interest in NERVA would force a loss of Grand
Tour in favor of a NERVA that had "no place to go."33

Meanwhile, NASA was trying to include Grand Tour as a new start in its
1972 fiscal budget. The Friedman report moved the Office of Management
and Budget (OMB), in March 1971, to ask NASA to study simpler, less costly
spacecraft alternatives to TOPS. The OMB also attempted to delay the Grand
Tour start-up to fiscal 1973. 34



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 261

OMB and congressional pressure to cancel TOPS and to cut NASA's budget,
combined with the debate induced by the Friedman report, left NASA management
in a quandary. In order to energize support for Grand Tour, and to answer
general questions about outer planet exploration, NASA administrators again
turned to the scientific community at a Space Science Board summer study
held at Woods Hole, August 8-14, 1971. Unlike previous summer studies,
this one concerned itself solely with outer planet exploration.

This latest summer study concluded that both Grand Tour (four TOPS probes)
and the intensive study of both Jupiter and Saturn ought to be supported.
Although the summer study scientists supported Grand Tour by a vote of
12-1, they cautioned that if NASA funding levels fell too low, Grand Tour
ought to be abandoned in favor of a Mariner spacecraft mission to Jupiter
and Saturn.35 The Mariner proposal
was a return to the original 1965 Woods Hole idea of exploring the outer
planets in piecemeal fashion.

As NASA prepared its fiscal 1973 budget, rumors spread that the "budget
pinch" was going to affect planetary programs deeply and that the reduction
of the Grand Tour payload from 205 to 130 pounds was "a likely fact of
life."36 Furthermore, Grand Tour now
began to compete for funding with the latest NASA human program: the Space
Shuttle. The fiscal 1973 budget request NASA submitted to the OMB on September
30, 1971 included both Grand Tour and the Space Shuttle. Throughout the
autumn of 1971, several press reports presciently reported Grand Tour's
vulnerability to a possible elimination or reduction .37
On December 11, 1971, James Fletcher, NASA administrator since April 27,
1971, learned from White House officials that Nixon was prepared to approve
the, shuttle program and that Nixon would not let NASA simultaneously fund
the shuttle and the full TOPS Grand Tour in the 1973 budget or in subsequent
fiscal years.38 Fletcher had to decide
which was more important: Grand Tour or human flight.

By December 16, 1971, Fletcher had agreed to delete the TOPS version
of Grand Tour from its fiscal 1973 budget request and to replace it with
a pair of less expensive Mariner spacecraft to be known as Mariner Jupiter-Saturn
to be launched in 1977. 39 The decision
to kill Grand Tour was not made public immediately, and it was terrible
Christmas Eve news at JPL. 40 Nixon,
in his budget message of January 5, 1972, announced the development of
the Space Shuttle, as well as the demise of TOPS Grand Tour and the substitution
of the more modest Mariner Jupiter-Saturn mission.

Who killed Grand Tour? The demise of Grand Tour was less a simple case
of its expensive price tag than its competition with other high-cost new
starts (the shuttle and the space telescope) and Viking in a shrinking
Federal and NASA budget. The smaller the budget became, and the more that
costly programs competed for those shrinking funds,



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262 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

the more expensive each program appeared. To some extent, too, Grand
Tour was a victim of the NASA preference for human space flight over scientific
probes. The Space Shuttle was essential to continuing the U.S. human space
flight program as Apollo wound down. The schism between how the planetary
scientific community defined outer planet exploration small, piecemeal
ventures and how JPL defined outer planet explorationa large, expensive
project to exploit a rare planetary alignment, and the public airing of
that schism, certainly contributed to the pressure on NASA administrator
James Fletcher to cancel Grand Tour. Thus, at NASA's fiscal 1973 budget
briefing on January 22, 1972, NASA administrator Fletcher explained that
Grand Tour was eliminated because of a "less than enthusiastic response
from certain elements of the scientific community particularly, and to
some extent, Congress."41

But was Grand Tour really dead? Even before the public announcement
of Grand Tour's demise, planning had begun for Mariner Jupiter-Saturn,
the reduced-cost, twoplanet alternative to Grand Tour recommended by the
most recent Woods Hole summer study. In December 1971, when NASA and the
OMB agreed to delete fiscal 1973 funds for the TOPS Grand Tour, NASA informed
the OMB that the JPL TOPS development group would be "retained and redirected
into planning a new program to explore Jupiter and possibly Saturn with
a three-axis stabilized Mariner-class spacecraft."42
(Stabilization along three axes was a requisite for onboard cameras.)

NASA administrators next turned to the scientific community in the guise
of the Space Science Board. The Board met February 8-9, 1972, and "unanimously
and warmly endorsed" Mariner JupiterSaturn. The Space Science Board, through
its chair Charles H. Townes, expressed the hope that the spacecraft would
remain operational beyond Saturn "and return very significant data on cosmic
particles and fields."43

Congress greeted with approval the replacement of the TOPS Grand Tour
with Mariner JupiterSaturn and authorized funds for Mariner Jupiter-Saturn
for fiscal 1973. The Mariner Jupiter-Saturn price tag, $360 million versus
$1 billion for TOPS Grand Tour, could fit into a scaled back NASA budget
that also financed development of the Space Shuttle. Although work on Mariner
JupiterSaturn started at JPL as early as January 1972, the new project
was not officially approved by NASA until the Contractual Task Order was
signed on May 18, 1972. 44

In order to reduce costs and overheads, NASA decided to leave design
and construction of the Mariner Jupiter-Saturn spacecraft to JPL, rather
than to Boeing, General Electric, Hughes, Martin Marietta, and North American
Rockwell, all of which had some level of preparation for a Grand Tour proposal.
The largest aerospace firms lobbied NASA Headquarters and Congress for
the contracts. In order for expensive projects to pass congressional scrutiny
as part of the NASA budget, they often had to include an intention to contract
out much of the work. Thus, for example, Magellan, the radar imaging mission
to Venus, although initially intended as a JPL in-house project for cost
reasons, was let out to Martin Marietta (spacecraft contract) and Hughes
(the radar contract).45 The decision
to go with JPL versus an industrial contractor was viewed at NASA Headquarters
by John E. Naugle, Associate Administrator for Space Science, as a "many
faceted problem" whose



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 263

resolution was "of paramount importance to the future of NASA's Planetary
Program as well as to the future of JPL." In short, JPL needed the contract
to maintain employment levels in the laboratory, and NASA Headquarters
needed it to maintain the vitality of its planetary program. Therefore,
he explained, "all of the various factors must be given careful and thoughtful
consideration."46

Despite the limited aim of the Mariner Jupiter-Saturn, the mission had
the Grand Tour launch window, that rare planetary alignment, and the engineers
at JPL still had every intention of building a spacecraft that would last
long enough to visit Uranus and Neptune. This intention was not emphasized;
however, it was stated that a Mariner Jupiter-Saturn spacecraft might continue
to Uranus if its mission at Saturn proved successful. The scientists working
on the project knew that Mariner Jupiter-Saturn was going to go to Uranus
and Neptune, too. As Bradford Smith, Leader of the Imaging Team, explained:
"We understood at the time the enormous potential of this mission that
it could very well be one of the truly outstanding if not the most outstanding
mission in the whole planetary exploration program."47

Grand Tour would rise from its own "death" as piecemeal additions to
Mariner JupiterSaturn. As S. Ichtiaque Rasool, Deputy Director of Planetary
Programs, Office of Space Science, reflected: "The lesson to be learned
from Grand Tour cancellation was that you never fund such a big, long-term
project at once. So we kept on adding piecemeal. And it's interesting that
they always come out big. When you have less money, you can even do better
sometimes."48 The Mariner design and
experience were used whenever possible and were supplemented with subsystems
designed for the Viking orbiter to provide the required performance and
reliability. NASA instructed the Atomic Energy Commission to upgrade the
plutonium batteries so they might last more than ten years, enough time
for Mariner Jupiter-Saturn to encounter Uranus and Neptune.49
Despite the reliance on extant technology, some money was set aside to
develop new technology. Congress and the OMB approved an additional $7
million to the Mariner Jupiter-Saturn appropriation for scientific and
technological enhancements. Part of that appropriation went to develop
a reprogrammable onboard computer,50
which proved vital to maintaining Voyager 2 as a functioning observatory
in space. Without properly functioning hardware, no science could be conducted.

just as scientists played a key role in shaping Voyager before it was
funded, they collaborated actively with NASA in defining the mission's
scientific objectives within organizational



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264 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

frameworks established by NASA. On October 15, 1971, although Grand
Tour had not yet been authorized, the space agency issued an "Invitation
for Participation in Mission Definition for Grand Tour Missions to the
Outer Solar System" to specify its scientific objectives, that is, typical
payloads and scientific instruments requiring a long lead-time to develop.
Among those primary objectives of Grand Tour (and Mariner Jupiter-Saturn)
were: 1. physical properties, dynamics, and compositions of atmospheres;
2. geological features; 3. thermal regimes and energy balances; 4. charged
particles and electromagnetic environments; 5. periods of rotation, radii,
figures, and other body properties; and 6. gravitational fields. While
travelling between planets, both missions would study variations of the
solar wind plasma and magnetic field, solar energetic particles, galactic
cosmic rays, and interplanetary dust. Once the spacecraft left the solar
system, they could make measurements of galactic cosmic rays unmodulated
by the solar plasma.51

Regardless of which objectives or instruments the scientific community
recommended, JPL insisted on including video cameras. At JPL, Harris M.
"Bud"
Schurmeier, JPL's Grand Tour and Mariner Jupiter-Saturn project manager,
understood both the non-scientific and the scientific importance of imaging
the planets and their satellites. In 1964, Ranger lunar-impact probes radioed
back the first close-up pictures of the Moon, thanks to hardware designed
at JPL under his guidance. Subsequently, in 1969, Schurmeier led the work
on Mariners 6 and 7 that achieved a hundredfold gain over
tiny Mariner 4 in the return of pictures from Mars, and in 1971,
Mariner
9 pictures of Mars, after waiting out a gargantuan dust storm. In addition
to the imaging team, Mariner Jupiter-Saturn would have a Radio Science
Team to exploit the scientific use of the spacecraft's radio systems.52
In selecting members of the scientific teams, the first members chosen
were those of the imaging and radio science teams, the teams using the
video and radio equipment that JPL intended to put on board, regardless
of whatever scientific instruments might be selected.53
As the NASA Field Center in charge of the mission, JPL thus could exert
a determining influence on the science to be conducted.

NASA, in April 1972, extended a formal request for experiment proposals
and received over 200 replies. From those the space agency selected ninety
scientists, mainly from the United States, but from France, Sweden, West
Germany, and Great Britain, as well.54
The selection process favored researchers in large institutional settings,
but did not filter out little scientists entirely. NASA policy was to select
scientists based on the merit of their research, as well as the "reputation
and interest of the institution." The stated reason for this selection
standard was to insure "scientific depth and breadth, and the availability
of the resources to support the investigation." NASA assumed that selected
scientists would be affiliated with an accredited academic institution,
a private corporation with sufficient contractual resources to provide
the required scientific, technical, and



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 265

administrative resources and support" (e.g., TRW or The Rand Corporation),
or a NASA or other government center or laboratory. 55

Illustrating how the scientist selection process favored those in large
institutional settings, such as NASA Field Centers, was the dominance of
NASA's Goddard Space Flight Center scientists on the infrared spectroscopy
and radiometry and the magnetic fields science teams. Eight of the eleven
members of the first team were from Goddard, while seven investigators,
only one of which came from outside Goddard (a German researcher) constituted
the magnetic fields team .56

University planetary scientists populated most of the other science
teams, although those scientists often counted on NASA funding for their
research. NASA grants to university funding and NASA's use of university
scientists drew them into the larger scientific enterprise of the NASA-industrial-academic
complex, thereby weaving little science into the fabric of large-scale,
big-budget science .57 Such was the
case of the radio science team, which was a mix of Stanford University
and JPL researchers.

The Stanford investigators, Von R. Eshleman, Thomas A. Croft, and G.
Leonard Tyler, came from that institution's Center for Radar Astronomy.
Founded in 1962, initially in collaboration with SRI personnel, and underwritten
by NASA, the Center for Radar Astronomy sought to conduct planetary atmospheric,
ionospheric, and surface studies using the radio equipment ordinarily (and
necessarily) included on each spacecraft, although special hardware often
was developed to perform experiments. The Center was small, however, in
terms of budget and personnel.58 The
remaining science team members, John D. Anderson, Gunnar Fjedlbo (now Lindal),
Gerald S. Levy, and Gordon E. Wood were all JPL staff engineers and scientists.
Fjeldbo, moreover, previously had been with the Stanford Center for Radar
Astronomy.59

Stiff competition, and at times personality conflicts, reigned among
the scientists submitting proposals.60
Among other factors, the selection or rejection of instrument proposals
hinged not as much on the qualifications of scientists or their research,
but on the



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266 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

trajectory of the spacecraft and the discoveries of earlier missions.
The assessment of the dangers of the asteroids, Saturn's rings, and Jupiter's
electromagnetic environment was placed on a firmer foundation by the results
beamed back by Pioneer 10 and 11, launched in 1972 and 1973,
respectively. Although the asteroid hazard appeared less threatening, Pioneer
10 encountered far more damaging radiation than had been expected.
Pioneer
11 reached Jupiter a year later (December 1974), then went on to Saturn,
where the spacecraft passed within 21,000 km of Saturn's cloud tops in
September 1979 and certified the safety of the narrow zone between Saturn
and its rings.61 These Pioneer
10 and
11 results led to the dropping and adding of Mariner
Jupiter-Saturn science experiments.

Once Pioneer 10 discovered that the levels of radiation at Jupiter
were a thousand times more intense then expected, NASA dropped an ultraviolet
photopolarimeter experiment that had been selected on a provisional basis.
In the place of that instrument, and at the urging of the concerned scientific
community, S. Ichtiaque Rasool, NASA Office of Space Science, included
on Mariner Jupiter-Saturn a plasma wave experiment which had been proposed
but not selected until then.62 On
the other hand, other science experiments were selected or excluded on
the basis of cost and spacecraft parameters. When drawing up the final
list of investigators and instruments in September 1973, NASA dropped the
micrometeorites experiment because of its development risk and cost, as
well as the difficulty of integrating it into the spacecraft design.63

Perhaps the most unusual Voyager scientific experiment was that with
no real Principal Investigator and essentially with no NASA budget for
instrument construction or data analysis; it was the recording entitled
"Sounds of Earth." On the chance that Voyager might encounter intelligent
extraterrestrial life, NASA approved placement of a phonograph record on
each of the two Voyager spacecraft. Recorded on a 12-inch copper disk,
"Sounds of Earth" ran for nearly two hours. Its contents, assembled by
a group of prominent scientists and educators led by Carl Sagan, who had
placed extraterrestrial plaque messages on Pioneers 10and11,
consisted of greetings from Earth in 60 languages, samples of music from
different cultures and eras, and natural sounds of surf, wind, thunder,
birds, whales, and other animals, as well as 115 photographs and diagrams
in analog form, depicting human beings, the solar system, DNA, and various
fundamental concepts from mathematics, chemistry, geology, and biology,
and greetings from President Jimmy Carter and the Secretary General of
the United Nations.64

The Voyager instruments and scientists selected, NASA then organized
the scientists into twelve (later reduced to eleven) science teams. Except
for the imaging and radio science teams, for which the project furnished
the instrumentation, the individual science groups were responsible for
designing and building the instruments associated with their



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 267

investigation areas. The eleven investigation areas were: imaging, radio
science, infrared and ultraviolet spectroscopy, magnetometry, charged particles,
cosmic rays, photopolarimetry, planetary radio astronomy, plasma, and particulate
matter. Specific scientific objectives included the study of the physical
properties, surface features, periods of rotation, energy balances, and
thermal regimes of the planets and moons and investigation of electromagnetic
and gravitational fields throughout the mission. Items of special scientific
interest included Jupiter's giant red spot and Saturn's rings and moons,
lapatus, Titan, and Rhea.65

Each science team had a leader, called a principal investigator, though
the heads of the imaging and radio science groups were designated team
leaders. The design and construction of the scientific instruments were
the responsibility of the principal investigators, who either could have
them built in their own laboratory or could contract for their construction.
The team leaders and principal investigators formed the Science Steering
Group, which had overall responsibility for advising NASA in the area of
Mariner Jupiter-Saturn science. By the end of 1972, Ed Stone, a magnetospheric
physicist from California Institute of Technology who had started on Grand
Tour in 1970, during the preplanning stage, was appointed Project Scientist.66
The Project Scientist stood at the interface between scientific needs and
engineering and budgetary constraints, between the Science Steering Group
and NASA, the public, the scientific community, and the press. In Stone's
own words, the Project Scientist served "an impedance matching function
between the engineering requirements and constraints and the science requirements
and constraints to try to find a way to achieve the optimum match between
these two different sets of requirements and desirements."67
In short, the management of science and decision making were centralized
in the Project Scientist.
Management of science included assuring that scientists' instruments
were built on time and within budget and that they fit spacecraft parameters,
especially payload weight, power requirements, physical and functional
interface conditions, exposure to radiation, and the telemetry budget,
that is, the allocation of down-link data bits without which data did not
return to Earth.68 The Project Scientist
also was the ultimate arbiter in deciding which experiments and which observations
would or would not be done. At times, the scientists lacked agreement on
which observations to make, and the Project Scientist had to decide which
of two equally good observations would be made. Rather than vote on the
issue, Stone made the decision himself. "It turns out," Stone reflected,
"that's a much more critical role than I had thought ahead of time, and
that's because ultimately what science is all about is making discoveries.
By deciding to make this observation rather than that one, you're effectively
deciding that that group of scientists gets to make a discovery and this
group doesn't."69

The most visible of the Project Scientist's activities as the interface
between the Voyager scientists and NASA, the public, and the media was
the press conference.



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268 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

The press conference was a keystone activity of the Project Scientist
in his role as mediator among Voyager scientists. Press conferences, not
scientific publications or conferences, were the venues where discoveries
were first announced. Dealing with the media and the scientific process
of discovery was the Project Scientist's major concern during the week
around each encounter. Every day, working with the scientists of each investigation
group, the Project Scientist had to determine what had been discovered,
which discoveries were ready for release, and how they would be released
in the press conferences.

The announcement of discoveries almost as they occurred, as well as
the very aggregation of scientists into working groups, raised the question
of intellectual property fights and priority of discovery. Ordinarily,
scientists would hold their own data as proprietary, not sharing with any
other scientist, so as to assure priority of discovery. However, not sharing
data, Stone believed, "would have inhibited the total development of the
scientific program"70

The idea of everyone sharing findings came to Stone from the need to
communicate those findings to the media. He attended the press conference
of Pioneer 10 when it encountered Jupiter. Stone, who previously
had worked only on Earth orbiting missions, was impressed by the scene:
"Here was a room full of reporters wanting to know what the scientists
had discovered. I mean, to me that was incredible. Normally there just
isn't that interest in what you're doing as a scientist. And here they
were day after day saying, 'Tell us what you've discovered. Tell us what
you've discovered.' I realized that with Voyager we had both the opportunity
and the obligation to communicate what we were discovering. To help the
media tell the story. But we had to do it in a scientifically credible
way."71 Having all Voyager scientists
share their data made the scientists act less as individuals and more as
members of a group, as they would on a typical big science project. The
initial publication of results, too, followed this big science group approach.
All of the initial publications resulting from a given encounter were published
in the same issue of a given journal, such as Science, Nature,
or the
Journal of Geophysical Research. All scientists, therefore,
published at the same time, but as a group, that is, one paper represented
the discoveries of an entire science team. There was no question of priority,
Stone explained, "everybody had equal priority, because everybody was there
at the same time."72The Mariner Jupiter-Saturn mission name persisted until March 1977,
only a few months before launch. Many within the project and within NASA
felt that the Mariner Jupiter-Saturn spacecraft departed enough from the
Mariner family that a new name would be appropriate. As early as 1971,
William H. Pickering, director of JPL, had suggested the name Navigator
for the spacecraft pair. 73 NASA organized
a name competition to choose the new name, and the winning nomination,
"Voyager," was approved on



---

Morabito, however, was not an outsider; on the contrary, she was part
of the JPL Voyager team, and her discovery was recounted in Science along
with the other Voyager science reports. Moreover, neither Morabito nor
anyone else outside the project "scooped" the Voyager science team. According
to Physics Abstracts, the first announcement of the discovery of volcanism
on Io was the IAU Circular of March 1979, issued by Torrence Johnson of
the JPL Voyager team. Morabito, S. P. Synnott, P. N. Kupferman, Stewart
A. Collins, "Discovery of Currently Active Extraterrestrial Volcanism,"
Science
204 (June 1, 1979), 972; 1 Johnson, E. E. Becklin, C. O. Wynn-Williams,
C. B. Pickett, and J. S. Morgan, IAU Circular 3338, March 16, 1979.

73. John E. Naugle to William H. Pickering, May 3,1971, record no.
005148, NASA Historical Reference Collection.



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 269

March 4, 1977. The name change, however, coming so close to launch date,
gave rise to a certain amount of confusion. References to Mariners 11
and 12 and even Voyagers 11 and 12 are a legacy of
this last change of name. 74

Despite the name change, Voyager remained in many ways the Grand Tour
concept, though certainly not the Grand Tour (TOPS) spacecraft. Voyager
2 was launched on August 20, 1977, followed by Voyager 1 on
September 5, 1977. The decision to reverse the order of launch had to do
with keeping open the possibility of carrying out the Grand Tour mission
to Uranus, Neptune, and beyond. Voyager 2, if boosted by the maximum
performance from the Titan-Centaur, could just barely catch the old Grand
Tour trajectory and encounter Uranus. Two weeks later, Voyager 1
would leave on an easier and much faster trajectory, visiting Jupiter and
Saturn only. Voyager 1 would arrive at Jupiter four months ahead
of Voyager 2, then arrive at Saturn nine months earlier. Hence,
the second spacecraft launched was Voyager 1, not Voyager 2.
The two Voyagers would arrive at Saturn nine months apart, so that if Voyager
1 failed to achieve its Saturn objectives, for whatever reason, Voyager
2 still could be retargeted to achieve them, though at the expense
of any subsequent Uranus or Neptune encounter.

The taking of such precautions was normal for a venture where a certain
number of spacecraft hardware breakdowns, called "anomalies" by NASA, are
considered to be normal. Most are minor and have no impact on the ability
of the spacecraft to carry out its scientific mission, such as the glitch
that occurred during the launch of Voyager 2. Nonetheless, these
anomalies emphasize the critical role that technology plays in the gathering
of scientific measurements from a space-based observatory. Without that
technology, no science is possible. The performance of the Voyager science
mission from the moment of launch is a lesson in the critical role played
by technology in the conduct of big science.

One serious anomaly that actually did limit the amount of Voyager science
conducted was that of the scan platform. On February 23, 1978, before Voyager
1 reached Jupiter, its scan platform became "stuck" during an azimuth
scan. The platform turned on three axes in order to aim the cameras, spectrometers,
and photopolarimeter in a scientifically useful direction. The platform
jam thus threatened to compromise critical scientific observations. Luckily,
command sequences transmitted to the spacecraft succeeded in moving the
scan platform; the crisis subsided.75

As Voyager 2 began to leave Saturn, and most of the scientific
observations had been made on the planet, its 220-pound scan platform became
stuck. The spacecraft cameras were sending back images of black space.
The heavy workload during encounter, combined with an ineffective lubricant,
likely caused the trouble, as engineers demonstrated on Earth-bound duplicate
equipment. To help alleviate the platform problem at Uranus, the spacecraft
was rolled when possible to perform large azimuth changes. The scan platform
was moved only for smaller changes, and then only at slower speeds.76

The scan platform jam at Saturn occurred after most of the scientific
observations had been made. Nonetheless, some science was lost. Whether
one considered that science critical depended on one's interests. Certain
project scientists wanted to play down the situation, and this annoyed
those scientists who suffered real losses. The loss of two images of the
moon Enceladus at a resolution of 1.6 kin was perhaps not as great as the
loss of the six



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270 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

images of Tethys at 1.7 km, because the best pictures available of that
moon had a resolution of no better than 5 km. The loss of coverage was
serious in the case of both moons, however, for now neither of them could
be measured all the way around with the precision that scientists would
have liked, or mapped as comprehensively as the mission cartographers had
expected. Other lost science included imaging the dark side of Saturn's
rings, and non-imaging lost data included a further occultation experiment
using the star Beta Tauri; infrared measurements of the ring material as
it entered the planet's shadow; ultraviolet spectroscopy of ring material
by observations of the Sun through the rings, as well as a field and particle
maneuver. In the judgement of Ed Stone: "We were fortunate that the platform
didn't stop a few hours earlier."77

The other major hardware failure was in the radio systems of Voyager
2. Voyager 2, which encountered more planets and moons than
its double, seemed to suffer the greater number of serious hardware failures.
No science was lost in this instance, although the potential was present,
and an attempt to repair the situation raised the possibility of creating
a spinoff ground facility for use in radio astronomy and ionospheric research.

In late November 1977, while the two Voyagers were still on route to
Jupiter, one of Voyager 2's two duplicate radio transmitters began
to degrade. It was switched to low-power mode to nurse it along. Something
was wrong, but there was no way to know exactly what. Months later, in
April 1978, the Voyager team discovered that Voyager 2's backup
receiver had failed to detect signals sent from Earth because of a shorted
capacitor. The primary radio receiver suddenly failed completely, as well.
Voyager
2 was silent. Continuing to Uranus and Neptune was no longer possible,
unless a way could be found to communicate with the backup receiver. Moreover,
the failure of the Voyager 2 primary radio system had potential
repercussions beyond the Voyager project. Its radio equipment was very
similar to that on Pioneer Venus, which was launched the following month,
in May 1978. 78

Normally, the radio receiver automatically compensated for the Doppler
shift of signals transmitted from Earth. The changing velocity and direction
of the spacecraft relative to Earth caused this Doppler shift. Without
the ability to compensate for the Doppler shift, the Voyager 2 radio
system could not detect any signals sent to it. The solution to Voyager
2's radio problems came from NASA Deep Space Network engineers. They
prepared computer tapes that slowly varied the frequency of the radio signals
transmitted from Earth in order to compensate for the expected Doppler
shift. The Deep Space Network station outside Madrid transmitted the first
test signals on April 13, 1978. Fifty-three minutes later, Voyager 2's
acknowledgement returned. The trick worked. As a backup measure, in October
1978, Voyager 2's memory banks were loaded to the brim with commands
that would provide



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 271

for a bare-minimum science encounter at both Jupiter and Saturn, should
radio contact once again be lost. The same procedure was followed for subsequent
encounters at Uranus and Neptune .79

The radio and scan platform breakdowns were not the only hardware failures
that threatened or curtailed Voyager science. Some of the scientific instruments
themselves experienced intermittent malfunctions and even complete breakdowns.
The high radiation levels at Jupiter caused difficulties in transmitting
commands, and the photopolarimeter instrument suffered radiation damage.
Moreover, in November 1980, as Voyager 1 was leaving Saturn, its
plasma instrument stopped transmitting usable data. A similar fault had
disabled the instrument for three months earlier in the year, as well as
back in February 1978. 80

In spite of the hardware problems that constantly threatened to diminish
the mission's scientific returns, Voyager encountered Jupiter and Saturn,
then continued on to Uranus and Neptune, following the Grand Tour route.
Piece by piece, the Grand Tour itinerary came together. The continuation
of Voyager to Uranus and beyond was made possible by reprogramming the
onboard computers, creating new software, and building new ground facilities,
new technologies and techniques without which the science could not be
conducted. The expansion of Voyager into an even larger scientific enterprise
also had spinoffs of value to the little science conducted on Earth. But
first, funding the extension to Uranus had to be approved.

In 1975, the Space Science Board recommended a Mariner Jupiter-Uranus
mission to be launched in November 1979, fly by Jupiter in April 1981,
and proceed to Uranus arriving in mid-1985. Mariner Jupiter-Uranus was
not the only mission under consideration by NASA. The space agency still
was attempting to cobble together a program of exploration of the outer
planets in the face of declining budgets. Other proposals included a Mariner
Jupiter Orbiter (later developed into project Galileo) and Pioneer missions
carrying atmospheric entry probes either directly to Saturn or to Uranus
via Jupiter.81

Mariner Jupiter-Uranus was planned for NASA's fiscal 1977 budget and
bore a price tag of $177 million, but it was in serious question because
of the Administration's announced federal budget squeeze. In May 1975,
NASA issued an announcement of opportunity for scientists to participate
in Mariner Jupiter-Uranus.



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An alternate solution to Voyager 2's radio problem considered
by NASA was to send commands through one of the science instruments, namely
the planetary radio astronomy receiver. Tests conducted during September
1978 using the Stanford radio telescope indicated less received signal
strength than had been anticipated, and the approach required both major
changes in the onboard computer programs and the construction of a suitable
ground transmitter facility. Implementation would cost an estimated $10
million ($7.5 million facility $2.5 million project) and would require
about twenty-four months to develop. Realizing that if the capability were
never used, NASA would be open to criticism for having built an unnecessary
facility, the Voyager Program Office decided against the planetary radio
astronomy solution. A. Gustaferro to Associate Administrator for Space
Science, February 1, 1980, and attachments, record no. 005566, NHO; Raymond
L. Heacock to Rodney A. Mills, 29 March 1979, record no. 005566, NASA Historical
Reference Collection; Von R. Eshleman, interview with author, Stanford
University, May 9, 1994, JPL Archives.

80. Rodney A. Mills, Voyager Program Manager, to Distribution, February
24,1978, record no. 005566, NASA Historical Reference Collection.

81. Burgess, Far Encounter, pp. 1 and 2; Davies, p. 39.



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272 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

Facing budget restrictions, still, NASA Headquarters dropped the project
from its fiscal 1977 budget request, causing a severe manpower problem
at JPL. 82 Adding Uranus to the Voyager
project, on the other hand, bore a price tag far less than that for Mariner
Jupiter-Uranus, about $100 million over five years, and it would bring
money to JPL. Approval of the mission extension was received in November
1980 and was based on
Voyager 1 achieving adequate Titan and Saturn
ring science and the health of
Voyager 2. JPL had a long lead-time,
five years, to prepare for Uranus: Voyager 2 would not reach Uranus
until January 1986.
83

The extension of the mission to Uranus and beyond required re-engineering
the spacecraft, which was already far from Earth, and upgrading Earth communication
facilities. These changes were compelled by the vast distances over which
the Deep Space Network had to communicate with Voyager, and by the dearth
of sunlight needed for imaging and certain scientific experiments. The
Sun at Uranus is only one fourth as bright as at Saturn and provides less
than one four hundredths of its earthly illumination. Television exposures
needed to be longer; camera shutter speeds reduced.

In upgrading the Mariner 10 camera to image Mercury, JPL engineers
developed a new electronic technique that read out the image signal three
times more slowly when desired. When the Voyager cameras were operated
in this slow mode, the lower radio transmission rate was adequate for realtime
communications from Saturn, because the video signals could still flow
directly from the camera to the radio transmitter and on to an attentive
Earth. While Voyager would use the same slow camera mode and transmission
rates at Uranus, additional techniques, namely compression and improved
encoding, were demanded.

Part of the $7 million of additional appropriation granted Mariner Jupiter-Saturn
in fiscal 1973 for technical improvements went toward design of an electronic
means for transmitting error-free data to Earth, what is known as Reed-Solomon
coding in honor of its inventors. Only basic coding hardware had been incorporated
into Voyager's computer when it was launched. For the Uranus encounter,
JPL engineers developed a special Reed-Solomon coding, which the Deep Space
Network transmitted to Voyager's computer. The improved encoding worked,
but it required more work on the ground.
Voyager engineers also used a technique called compression to obtain
images from beyond Saturn. Normally, the full light-intensity value of
each pixel of every image is transmitted back to Earth. Compression consists
of sending back only the difference in light intensity between adjacent
pixels on each line of each image. The technique reduced the communications
rate needed by a factor of two and a half. But, in order to exploit compression,
the spacecraft's computers had to be assigned new tasks, and that involved
a certain risk. If a problem arose with the primary flight data computer,
while the backup computer was tied up executing compression commands, key
scientific observations, or even the entire mission, might be lost.84

Following the Grand Tour road to Uranus and Neptune also required revamping
ground-based communication facilities. The distance to Uranus was over
a billion kilometers. Signal strength was about one-fourth the level of
the Saturn fly by in 1981, when Voyager was transmitting from a distance
of 605 million kilometers. Existing ground-based Deep Space Network facilities
were unable to adequately communicate with



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 273

Voyager at those great distances. The solution was to array antennas
together, a technique commonly used in radio astronomy. At the Deep Space
Network site outside Canberra, Australia, two 34-meter and one 64-meter
dish antennas were arrayed together. In addition, through an international
agreement, NASA linked its Deep Space Network Canberra dish antennas with
the 210-foot Parkes radio astronomy telescope located 200 km away via a
microwave connection. Of the three Deep Space Network locations, that in
Australia would have the best view of Uranus during Voyager 2's
ring plane crossing and closest encounter with the planet.85

A similar arrangement was put together at the Deep Space Network site
at Goldstone, California, for the Voyager encounter with Neptune. Because
Neptune is three times farther away from Earth than Saturn is, the Voyager
X-band radio signal would be less than one-tenth as strong as during the
Jupiter encounter in 1979 and less than one-half as strong as during the
Uranus encounter in 1986. Part of the Voyager upgrade of the Goldstone
64-meter antenna involved enlarging the dish diameter 70 meters, increasing
the surface accuracy, and improving the receiving system, as well as the
installation of 34-meter antennas, to be used in an array formation, at
the Goldstone and Canberra Deep Space Network sites.86

NASA approached the management of the Very Large Array (VLA), a radio
telescope located in New Mexico, about participating in the formation of
an antenna array with the Deep Space Network dishes at Goldstone, in order
for NASA to communicate with Voyager at Neptune. The space agency installed
low-noise X-band receivers on each of the 27 VLA antennas. Through the
radio astronomy technique of arraying, and the installation of low-noise
receivers on each VIA dish at NASA's expense, the echoes received from
the VIA were combined with those received at the Goldstone 70meter and
34-meter dishes to provide a data rate more than double that which would
have been available with Goldstone's antennas alone. Just as with the Parkes
radio telescope, a microwave link permitted NASA to array the VIA and Deep
Space Network dishes at Goldstone .87

The Voyager upgrade of the VLA inadvertently created a state-of-the-art
facility for planetary radar astronomy, a scientific activity that was,
and remains, little science in terms of manpower, instruments, budget,
and publications, but which took root within the interstices of big science.88
When radar astronomers linked the Goldstone radar and the VLA in a bistatic
mode, that is, with Goldstone transmitting and the VLA receiving, they
created a radar with an extraordinary capacity for exploring the solar
system. Duane O. Muhleman, California Institute of Technology, his graduate
students Bryan Butler and Arie Grossman, and Martin A. Slade of JPL have
used the GoldstoneVLA facility to explore Titan, Venus, Mars, and Mercury.
Their exploration has led to a number of major discoveries, including the
presence of polar ice on Mercury.89



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274 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

As Voyager travelled from one planet to another, from one spectacular
and unexpected discovery to the next, scientists and the public marvelled
at the outcome of this scientific expedition. In the words of Project Scientist
Ed Stone: "There's one lesson we learned from Voyager: Nature is much more
inventive than our imaginations."90 The Voyager
mission truly deserved the honor of the 1980 Collier Trophy. Moreover,
its subsequent accomplishments beyond Saturn in the face of hardware and
budgetary hindrances have merited further recognition.

The crucial role played by technology in the success of the Voyager
scientific mission allows us to draw some conclusions about the nature
of big science. Obviously, Voyager science was entirely dependent on the
availability of the spacecraft and its assemblage of scientific instruments.
Hardware failures threatened the loss of science. That science depended,
too, on the availability and proper functioning of an extensive network
of telecommunication facilities on Earth. A similar dependence on technology
is found in ground-based planetary astronomy.

The technologically driven nature of Voyager science raises questions
about the epistemology of space-based science. In an Earth observatory,
an astronomer can look through the lenses of a telescope and see the object
of study. Using a space-based observatory, such as the Voyager spacecraft,
scientists do not experience nature as directly as through a telescope.
Instead, a scientific instrument makes the observation, then electronic
circuitry aboard the space-based observatory converts the observation into
strings of digital bits and transmits those bits to Earth, where a Deep
Space Network facility acquires them. Through various signal-processing
stages, which require extensive manipulation by large computers, the strings
of digital bits transmute into data, which scientists then study. It is
this data that scientists study and from which they draw conclusions about
the phenomena that interacted with the scientific instrument in space.
Data, rather than direct observation, has become the object of research,
and that change has required inclusion of certain assumptions about the
relationship between phenomena and the data. Thus, the instrument of scientific
research is no longer just the spectrometer or the telescope (to use an
Earth-bound analogy), but the observatory and the totality of electronic
operations (both telecommunications and computing) required to turn the
observation of the instrument into data. Historians of science need to
explore how computers, signal processing, and other electronic techniques
have come to mediate between the observer and the observed and to determine
to what extent this transformation has been precipitated by the advent
and growth of big science. Clearly, though, it is large-scale technology
and techniques that make possible the science.

The Voyager project was an example of big science as measured by a number
of yardsticks, such as the number of planets, satellites, and rings studied,
mission longevity, and cost. At the same time, little science was an integral
part of the project. The creation of the Goldstone-VLA array to receive
Voyager images from Neptune also furnished radar astronomy's little science
with a facility. More directly, university based scientists became part
of Voyager big science through their organization into science teams and
through the centralization of science and other decision making in the
Project Scientist. The literature holds additional examples of big science
as the centralization and management of little science.

James Watson, former head of the Human Genome Initiative, claims the
project utilized a "little science approach" partly because only its management,
and not the work, was centralized. In her study of fusion, Joan Lisa Bromberg
argues that centralizing the research decision-making process, rather than
centralized facilities, defined the institutional boundaries of big science.
James H. Capshew and Karen A. Rader, furthermore,



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FROM ENGINEERING SCIENCE TO BIG SCIENCE 275

contend that activities that are broad in scope, scientific exploration
being a specific example they cite, are big in the sense that they require
coordination among geographically dispersed investigators or facilities.
Consequently, the hallmark of such Big Science is horizontal integration
and a reliance on extensive communication networks and centralized work
processes.91 The history of Voyager
shows that yet another example of big science as horizontal integration
of science management is the organization of the geographically dispersed
Voyager scientists into teams and the concentration of decision-making
in a single individual, the Project Scientist.

Within the NASA-industrial-academic complex, little science and big
science do not always dovetail. The discussions of outer planet exploration
within Space Science Board summer studies leading up to the decision to
terminate Grand Tour illustrate this point. Planetary scientists wanted
Jupiter-intensive studies and separate missions to the individual outer
planets, while NASA (especially JPL) wanted to send numerous spacecraft
to the outer planets, but each one taking advantage of the rare Grand Tour
launch window. The division between JPL and the planetary science community
stemmed largely from their divergent interests. The primary activity of
JPL and NASA was the designing, building, and launching of vessels for
the (preferably manned) exploration of the solar system. The planetary
science community, on the other hand, wanted to do science, rather than
build spacecraft.

Despite this division, NASA and the planetary science community had
much in common. As Joseph Tatarewicz has shown, NASA has transformed American
ground-based planetary astronomy into big science through its financing
of the scientific enterprise.92 By
funding the construction and launching of spacecraft laden with scientific
instruments, NASA also has positioned itself as the patron of space-based
big science. NASA funding of both space-based and earth-bound planetary
science is not the only way in which NASA has incorporated little science
into big science. The organization of scientists into investigation areas
and the centralization of the management of science into the Science Steering
Group and the Project Scientist on the Voyager mission was another way
in which NASA weaves little science into the larger fabric of big science.

This brief over-view of Voyager stressed the critical role of properly
functioning technology in the success of the scientific mission. The dependence
of science on instrumentation for observation and the need for science
funding is at the core of the relationship between big science and little
science. Critical, too, is the inescapable fact that planetary science
is based on observation. Without the Voyager observatory and its payload
of instruments, planetary scientists would have been without data, without
observations. NASA funding also paid for the scientists to participate
in the project. To what extent could planetary science be conducted without
NASA and the trappings of big science?

And by any estimation the planetary science conducted by Voyager was
impressive. just a partial list would include the following, and fully
justify the recognition the mission has received:

- Discovery of the Uranian and Neptunian magnetospheres, both of them highly
inclined and offset from the planets' rotational axes, suggesting their
sources are significantly different from other magnetospheres.
- The Voyagers found twenty-two new satellites: three at Jupiter, three at
Saturn, ten at Uranus and six at Neptune.
- Io was found to have active volcanism, the only solar system body other
than the Earth to be so confirmed.

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276 VOYAGER: THE GRAND TOUR OF BIG SCIENCE

- Triton was found to have active geyser-like structures and an atmosphere.
- Auroral zones were discovered at Jupiter, Saturn, and Neptune.
- Jupiter was found to have rings. Saturn's rings were found to contain spokes
in the B-ring and a braided structure in the F-ring. Two new rings were
discovered at Uranus and Neptune's rings, originally thought to be only
ring arcs, were found to be complete, albeit composed of fine material.
- At Neptune, originally thought to be too cold to support such atmospheric
disturbances, largescale storms (notably the Great Dark Spot) were discovered.

As big science became the dominant way of doing science in the latter
half of the twentieth century, what we call little science has become a
necessary and integral part of Big Science. In the case of Voyager, spinoff
facilities, summer studies, and, above all, the organization of scientists
into the Science Steering Group, integrated little science into the overall
big science undertaking. Many Earth observatories continue the tradition
of blending little and big science. Individual scientists from universities
request time on a large telescope, usually funded by public money, in order
to make observations. The scientist might have funding from the National
Science Foundation or NASA. There is no longer a distinction between big
science and little science, but a single scientific enterprise in which
the two are woven together in a set of interdependent relationships, each
part of the same fabric.

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