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PART A: SPACE SCIENCE

SECTION TWO: HISTORICAL - SOCIOLOGICAL REPORT
(By Joel Genuth)

I. INTRODUCTION
[Table of Contents]
This essay serves two overlapping purposes. First, it discusses those aspects of multi-institutional collaborations in space science that are most important to generating or locating documents of likely interest to historians of science and technology. In this sense, it provides the empirical perspective necessary for archival analysis and appraisal guidelines to be well grounded in the realities of recent research. Second, it offers observations on where the institutional framework of the government-funded, multi-institutional collaboration has seemed to affect (or leave undisturbed) the social relations and acquisition of expertise that are necessary for the pursuit of scientific research. In this sense it provides a preliminary perspective on social patterns and changes within a scientific community.

The foundation for this essay is 102 interviews with participants in six multi-institutional collaborations in space science. All the collaborations contributed to spacecraft that were launched between 1975 and 1985. (In the terminology of the field, "project" refers to the collaborative effort to launch, operate, and analyze data from spacecraft; we will henceforth use "project" in the space scientists' sense.) In our choice of projects to study, the American Institute of Physics staff and consultants consciously tried to cover a range of features: projects managed by different space flight centers, projects whose participating scientists came from a variety of institutions, international and nationally organized projects, astrophysical and planetary science projects, and smaller and larger projects. In our choice of interviewees, the AIP staff sought to cover all the types of people who might be vital to the documentation of scientific work, from administrators at funding agencies to graduate students at university departments. The strategy was to learn a little about a lot in the belief that broad exposure was essential to producing sound recommendations for archivists and policy makers. We also aimed to provide a context that others scholars can compare with their own case studies, which will likely remain the dominant mode of inquiry into "big science."

The structure of the essay owes much to the large overlaps and infrequent divergences in the two major purposes. The first three sections, Project Formation, Project Organization and Management, and Activities of Experiment Teams, roughly place comparisons and contrasts among the projects in the narrative categories of beginning, middle, and end. The last four sections, Funding, Internationalism, Careers, and Communication, put the comparisons and contrasts in non-narrative functional contexts in order to highlight the structural similarities and differences among the cases. There are overlaps in the content among the two sets of sections; the fuller exposition is in the narrative categories, which contain some material not found elsewhere.

The preeminent finding of the historical analysis are that National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) headquarters and flight centers impose a formal structure on space science projects. However, projects formed for a variety of reasons and in a variety of ways, and participating scientists and engineers have been able to modify the mandated structure to fit their circumstances. Space science projects, during the time period we covered, originated both inside and outside the flight centers, and scientists joined projects through both formal competitions and informal recruitments by "network- ing" organizers. These differences affected who within the projects collected information, the breadth of scientific interests participating in the projects (and through them, the disciplinary communities addressed by the projects), and the level of prior working relations that participants brought to the projects. On this last point, we concur with the consulting sociologist, Lynne Zucker, that building "trust" is important to the performance of these collaborations.

II. PROJECT FORMATION IN SPACE SCIENCE
[Table of Contents]
The origins of our selected projects go back in time as far as the mid 1960s. Only in the two earliest [IUE and Einstein][1] was there confusion and conflict over the institutional settings of expertise needed for successful space-based research. For the rest, problems of rocketry, spacecraft structure, thermal balance, power supplies, spacecraft operations, and telemetry had all come to be understood as "engineering" and under the control of engineers, even though engineers lacked professional interests in making and analyzing space-based observations. To participate in the design of a space project, scientists have had to be members of institutions that had engineers or could contract with engineers to address these topics. Furthermore, since the point of designing a project has been to bring about its fabrication, project-creating scientists have needed to be aligned with engineering institutions with which funding agencies have wanted to do business.

The NASA space flight centers and the European Space Research and Technology Centre (ESTEC), the lone ESA space flight center, have made it their business to take responsibility for the engineering essential to space projects, and the scientists at NASA centers have made it their business to agitate for projects they believed would serve the interests of their centers and a scientific community. (Scientists at ESTEC are less entrepreneurial but can provide important organizational support to external scientists campaigning for a project.) The flight centers' prominence as homes to space project expertise have enabled the agencies to place a modicum of bureaucratic formality on the formation of projects. In "Phase A," studies have been commissioned to ascertain the technical feasibility of a project that has attracted interest through informal study and thus seems credible to flight center and headquarters officials. Desirable results have led to "Phase B," in which spacecraft designs are refined and construction costs estimated, with the goal of receiving an authorization to build the spacecraft and their payload(s) of scientific instruments.

While flight centers have no doubt been the most significant institutional generators of space science projects during the period we covered, they did not monopolize the necessary resources for creating such projects[2]. In the United States, a few research laboratories, through Defense patronage, have combined spacecraft-construction capabilities with scientific expertise in the design of research instruments to be flown on spacecraft (e.g., Johns Hopkins Applied Physics Laboratory and American Science and Engineering in our case studies). In Europe research institutes have likewise acquired that combination of capabilities with the support of individual national governments (e.g., Rutherford Appleton Laboratory, Max Planck Institute for Extra-terrestrial Physics). Scientists in university departments, however, lacked the resources to play a role in the creation of our selected projects. (It is not clear whether this result is an artifact of our selection of case studies; one obvious counter-example is that Robert Smith found Lyman Spitzer of Princeton to have been the central proponent of the Hubble Space Telescope[3].) The only corporate scientists to instigate a project shifted their institutional base to a linked government-university setting (American Science & Engineering scientists on Einstein). Our anecdotal evidence suggests that, with idiosyncratic exceptions[4], the individual universities that tried to acquire and maintain spacecraft-design expertise eventually found the endeavor too expensive and therefore specialized in the design and use of research instruments. Conversely, aerospace firms have specialized in spacecraft construction, because their research groups developing scientific instrumentation could not be both profitable and competitive with universities charging lower overhead rates and employing graduate students for skilled labor.

Given the truism that space projects form at the intersection of scientific opportunities with engineering capabilities, our case studies reveal a variety of inspirations for forming projects and a variety of channels through which social connections have been made among scientists and between scientists and engineers. Two principal distinctions characterize our selected projects in their formative stage. Four of the six projects came to the attention of headquarters decision-makers through the flight centers [IUE, Voyager, ISEE, and Giotto] while the other two originated on the outside [Einstein and AMPTE]. Four of the six cases—including the two that formed outside the flight centers—took their scientific impetus from prospects for improved measurements of physical processes [Einstein, AMPTE, IUE, ISEE]. The other two relied on opportunities created by rare astronomical configurations [Voyager and Giotto]. When flight center staff members instigated measurement-improving projects, they had to demonstrate their projects' engineering credibility, whereas when offering a spacecraft to investigate a rare natural event, they had to demonstrate scientific credibility. In either case, instigators have needed to convince an advocate at agency headquarters of the project's viability within the politics of the agency's budget. When outside scientists instigated projects with little help from a flight center, their principal difficulty was to find a route into the politics of the agency's budget. The existence of the projects we have studied attests to the wisdom, flexibility, or luck of their instigators in dealing with the representatives of engineering, scientific, and institutional interests in the politics of funding.

The flight center instigators for projects pursuing better measurements have been scientists in charge of flight center laboratories or branches. To turn ideas into designs, scientist-instigators had to sell flight center engineers on their ideas, since the engineers would be busy with extant projects and subject to recruitment by other would-be project instigators. In our cases, these in-house campaigns for a project were conducted informally. Scientist-instigators would directly talk up their ideas with engineers, lobby upper-level center administrators (whose encouragement would be of obvious utility in enlisting talent), and organize on-site meetings of interested external scientists (whose presence indicated a serious interest in a project). In one case [ISEE], an engineer helping with preliminary design studies recalled that a scientist-instigator organized a meeting of external scientists at the flight center to discuss the project and used a cocktail party connected to the meeting to buttonhole the director of the flight center about supporting the project. It was through that informal show of political strength, according to the engineer's memory, that the project acquired the credibility within the flight center to attract the engineering support needed for Phase A studies. In another case [IUE], a project quickly acquired in-house credibility because an upper-level administrator was temporarily serving as director of the relevant science division.

The two projects that took advantage of rare astronomical configurations were initially seized on by spacecraft designers at flight centers. In one case [Giotto], the space flight center had nobody with longstanding interest in the science of the project. In the other, while the flight center could make use of interested scientists, the spacecraft designers used the potential for a project to initiate a sub-system development program to bring new technologies into spacecraft engineering. Both projects depended on demonstrating the existence of a scientific community willing to work out and then build a payload of instruments for the spacecraft. When ESA officials have needed assurances that scientists support the plans of ESTEC, the deliberations of the specialized working groups reporting to ESA's Science Advisory Committee have been critical. When NASA officials have needed such assurances, they have looked to the National Academy's Space Studies Board (or the Board's relevant subcommittee) or to one of the advisory boards of external scientists created by NASA's Office of Space Science and Applications[5].

Regardless of whether a project pushed from a flight center originated with scientists with ideas for better measurements or engineers with ideas for getting scientists to a rare natural event, project instigators have cultivated an agency headquarters scientist to promote the project within the agency's budget deliberations. Headquarters scientists, whose sense of accomplishment has depended on successfully promoting projects, have been receptive but discriminating consumers of suggestions. They have consistently used "Working Groups"[6] to judge or refine the outlines of projects. Depending on the size of the project, working group deliberations have been either the principal hurdle for project instigators, or one major step in a longer path to approval.

Three of the four measurement-improving projects we studied in the United States were "Explorer-class," meaning they were eligible for funding from an established line-item in the NASA budget for smaller scientific missions and thus never directly scrutinized by Congress or the Office of Management and Budget. Their promoters at Headquarters were "discipline scientists," who needed the approval of the Associate Administrator for Space Science to place a project in the Explorer queue. A principal hurdle to obtaining that approval has been the discipline scientist's own standing Working Group. Because such working groups have included devotees of experimental techniques of relevance to a discipline, any project featuring one technique faced reflexive opposition from working group members wishing to save slots in the Explorer queue for their own. Thus if a discipline scientist's Working Group subscribed to a project, that was a good indicator of the project's general significance.

One measurement-improving project among our case studies and both projects that took advantage of rare astronomical configurations were expensive enough to require explicit authorization from the full agency (not just the agency office handling science programs) and higher political levels[7]. Their partisans first had to obtain a directorate-level official from the science office to promote the project. In one case, the flight center scientist who was interested in the project initiated a petition among outside scientists to catch the interest of an appropriate official [Giotto]. A directorate-level promoter, in addition to the work needed to convince political authorities of the value of the project, also had to manage the working groups. These working groups have been either standing parts of an agency's structure or groups assembled ad hoc to consider possible payloads for a particular mission. Their success at outlining a payload constituted evidence of broad support for the project in the scientific community.

The reward to the headquarters scientist who succeeded in agency budget politics has been to participate in drafting an Announcements of Opportunity (AO) and then to lead in the selection of proposed experiments. This selection was influenced by the comments of peer reviewers, engineering assessments of the proposals, and the sensibilities of the headquarters scientist's administrative superiors.

Space scientists seem to have accepted the necessity of empowering headquarters scientists to decide among proposals that differed significantly in cost, level of technical risk, or science strategy. There were very few accounts of research scientists who succeeded in attempts to limit the discretionary authority of headquarters by coordinating the production of proposals. In the measurement-improving projects, the principal investigators (PIs) we interviewed usually portrayed themselves as passively awaiting the AO and then enlisting the signatures and advice of co-investigators to the proposals they drafted. The effort to establish the scientific and engineering credibility of a project effectively warned an entire scientific community to prepare for an AO, yet in only one instance [ISEE] did two potential competitors unite in anticipation of the AO in order to create one proposal that increased the chances that both would participate by decreasing the options of the headquarters scientist had for that experiment's slot.

In some projects, working groups drew up "straw-man payloads" to guide the competition for slots on the spacecraft. Scientists viewed participation in such working groups as an opportunity to embed a preferred instrumentation approach into project planning and to build up a team to propose that instrument once the AO was issued. However, we encountered several instances in which such "front-loading" of the competition failed. In two cases the "proto-teams" disintegrated into competitors over scientific or personality conflicts, in two others non-participants in the working groups won space for their instruments in the final payload, and in two others scientists successfully proposed to fly species of instruments that were not included in the initial plans. Our anecdotal impression is that scientists who do not participate in working groups are still viable competitors for the space in a payload.

Both of the projects that originated from outside the flight centers [AMPTE and Einstein] came from institutions whose engineers had previously designed and built satellites under government sponsorship. The importance of engineers to scientist-instigators can be seen in a counter-example. One of the intra-flight center projects we studied [IUE] had its intellectual origin in a twice-failed attempt to initiate a project from outside the flight centers. The project's would-be scientist-instigators, who were not employed at institutions with satellite-designing engineers, had initially proposed a scientific payload that could achieve its desired results only if the rest of the satellite's systems met prohibitively expensive specifications. After the proposal failed, the scientists consulted engineers and produced an integrated proposal that more cost-effectively balanced the burdens on the scientific payload and the rest of the satellite. When agency officials still doubted the project's fiscal feasibility, the instigators peddled their ideas to a flight center that had not been involved in the initial deliberations. Scientists at the new flight center modified the proposal to incorporate planned engineering developments, thereby making the project more scientifically appealing and an excellent challenge for the center's engineering staff. Thus from a failed outsider-instigated proposal emerged a successful flight center supported project.

The principal hurdle to the formation of the two projects instigated with minimal flight center support was the lack of a straightforward route into the agency's formal project-forming procedures for instigators with engineering support from outside the flight centers. In one major respect, the two sets of instigators used similar tactics to impress themselves on agency authorities. The instigators persuaded leaders in relevant experimental techniques to sign onto integrated proposals under a self-invented title other than principal investigator, which was reserved for the instigators themselves. The point, according to one of the recruits, "was to present to NASA something that was too good to turn down ... [viz.] the participation of [all] the major players ... so that there wouldn't be any serious competition from outside." The result was a partial subversion of a headquarters scientist's normal prerogatives. Another recruit thinks of a phone call from an instigator as "the only time we kind of were selected," though the individual added that an agency-run competition would have changed nothing because nobody else at the time had developed an instrument with comparable measuring power. In principle, the agency could have broken up the self-made collaboration and reconstituted the project with multiple PIs; one recruited scientist recalled being advised not to put effort into the instigator's proposal because the agency would never go for a "done deal." An important question for future study is whether measurements can be made of how frequently "done deals" have been proposed and whether their success rate differs from proposals for multi-PI projects.

Otherwise, the two outsider-instigated projects reached acceptance through contrasting political courses and contrasting claims of scientific benefits. One set of instigators [AMPTE] expanded the project's social base by calling theorists' attention to the project's potential to take data that could discriminate among competing theories. (However, the instigators were careful to maintain opportunities for participating scientists to use the project for generic exploration.) The other set [Einstein] expanded its social base by calling outside experimentalists' attention to the project's potential to accommodate guest users with diverse interests. (However, the instigators were careful to reserve operating time for experiment-building scientists to use for their own research.) Instigators of one project [AMPTE] successfully courted a headquarters discipline scientist, but one whose branch lacked the power to do more than keep hope alive with a slow stream of study funds. Only an Announcement of Opportunity from elsewhere in the agency created a niche within which the collaboration could compete for spacecraft- and experiment-construction funds. Instigators for the other project [Einstein] failed to make the appropriate headquarters scientist an early partisan for the project. Headquarters took notice because National Academy meetings called attention to the complementary scientific interests and common engineering needs of the projects of several prominent would-be instigators. That piqued a work-hungry flight center to design a program that fit the several projects. When a directorate-level advisory committee endorsed the program, the agency made it a major initiative.

Developments in headquarters beyond the influence of project instigators buffeted both these projects, but with opposite effects. In one case, delays in funding brought the project a larger-than-anticipated launch rocket, which enabled the scientist-instigators to create a larger project than originally planned. In the other, severe cutbacks in the budget for the program obliged the scientists to endure conflictual discussions over how best to "descope" themselves before the engineers at headquarters did it for them. In neither case did the conflicts lead to forced or voluntary resignations from the projects, but these cases do demonstrate the importance of intra-agency conditions and policies for social relations within space science projects.

We suggest the possibility of constructing a spectrum of project types and correlating the types with the social origins of the projects (at least for projects that first formed circa 1970 and were launched circa 1980)[8]. The project types range from community-reforming at one extreme to community-affirming in the middle to community-creating at the other extreme.

Community-reforming projects are represented by a project [AMPTE] that mobilized an extant community of experimenters by directing their attention to a particular scientific issue (while making possible other measurements compatible with the central work). The community-affirming projects are represented by projects [IUE, ISEE, Voyager, Giotto] that provided a better vantage point for an extant community to measure natural objects or environments of longstanding interest. Community-creating projects are represented by a project [Einstein] that developed a family of measuring techniques and shared their use with scientists the instigators believed should become supporters of their techniques. The community-affirming projects originated in flight centers, whose scientists made it their business to find advantageous spacecraft configurations or combinations for their peers, or whose engineers tapped scientists' enthusiasm for using rare astronomical configurations to create spacecraft-designing opportunities for their flight centers. The two extremes are outsiders' projects, whose instigators used "scientific charisma" to organize scientists into a single-PI structure in a way that would have seemed an excessive exercise of governmental power if attempted by flight center scientists.

III. ORGANIZATION AND MANAGEMENT OF SPACE SCIENCE PROJECTS
[Table of Contents]
NASA Headquarters has imposed a formal structure on space science projects. Program managers, engineers by training, at NASA Headquarters have overseen project managers, also engineers by training, at NASA space flight centers. Project managers have overseen the design, construction and integration of spacecraft, including their payloads of scientific instruments, by employing some combination of in-house engineers, external industrial contractors, and in-house and external PIs. The PIs, scientists by training, have designed and built scientific instruments using some combination of staff engineers or scientists, external contractors, and co-investigators. A project scientist, typically a PI and an employee of the space flight center, has been responsible for advising the project manager on spacecraft engineering options that could affect the project's scientific capabilities and for keeping the other PIs informed of spacecraft engineering developments. To discuss collective scientific concerns and resolve them, the project scientist has led meetings of a "Science Working Group" (SWG). The precise membership of the SWG has varied across projects but has always included all the PIs and select members of their teams. The project scientist has also reported to a program scientist at NASA Headquarters, who has been able to bring scientists' concerns to the program manager or their mutual superiors within the Office of Space Sciences and Applications (OSSA).

These arrangements have attempted to manage an intrinsic tension in the concept of space science projects: which is the more difficult and significant challenge—sending and operating equipment in space, or satisfying criteria of scientific value? Space projects, whether pursued for science, national security, international prestige, or commercial advantage, have had common problems of design and operations; vesting managerial authority for space science projects in engineers well versed in spacecraft has placed scientists under a discipline of useful expertise that has often not been part of their own professional training. However, science projects, whether pursued in space, the natural earth environment, or the laboratory, have been valuable only if they yielded new or improved data; providing scientists with their own line of communication to OSSA's higher authorities has reminded engineers that they must serve as well as manage the PIs. In space science projects, NASA's answer to the science policy question of whether scientists should be on top or on tap has been "some of each."

The multiplication of lines of power built into the formal structure of space science projects has insured that even projects that fit well into that structure will vary significantly. A fortiori, projects that grafted the formal structure onto a structure of their own making created even more variance. Instances of both kinds of variation are well represented in the projects we studied. Nevertheless, the formal structure, whatever its defects as a description for how the projects have been organized, does create consistent terminology for identifiable elements of space science projects. We will accept the terminology and work towards an assessment of the character of these elements and their relations to other aspects of the projects.

A. The Scope of the Science Working Groups
[Table of Contents]
Science Working Groups in our sample varied in how much business they handled. Scientists appear to have been torn between limiting the scope of the SWG, and thus maximizing their autonomy from each other, and expanding the scope of the SWG, and thus maximizing their unity in dealing with project engineers and outside scientists. The policy of scientists in any particular project depended on the project's origins and the way in which the project's participants joined up. Projects that originated within the space flight centers and that were staffed with PIs chosen through a competition organized by NASA Headquarters had relatively circumscribed SWGs in comparison to projects that originated in outside laboratories and that were staffed with scientists recruited by the projects' scientific instigators.

In the most extreme of our case projects [IUE], the SWG was initially ceremonial. Its members were not PIs in the sense of experiment builders, because the flight centers planned to build the spacecraft entirely on their own for outsider users; they were scientists who had submitted early proposals to use the spacecraft once completed. This SWG's function, even in the eyes of its members, was to demonstrate the existence of community support for the project outside of the NASA flight center. Its advice "rubber-stamped" what the flight center scientists and engineers had decided was the proper course. The SWG's efforts became more meaningful as the project grappled with observatory operations and data processing. But nobody pointed to the SWG as an important body for determining the character of the observatory or the science it made possible.

More commonly, the SWG restricted itself to dealing with collective issues that were engineered into the project's initial design. In all projects (except the one discussed in the preceding paragraph) in which the instruments, upon integration and testing in the spacecraft, disturbed each other, the SWG provided a forum for working out procedures to minimize interference in operations. However, special steps were sometimes instituted in projects with magnetometers, which are highly sensitive to electromagnetism. The cases we studied included one [ISEE] in which the SWG took on the issue of minimizing the spacecraft's electromagnetic noise, and one [Giotto] where the magnetometer's PI had to work out problems individually with the builders of systems that could create noise. For planetary projects, the flight path of a project's spacecraft(s) was the outstanding example of an SWG issue. Because a spacecraft's course could determine what scientists could measure, spacecraft trajectories and orientations were always subjects of SWG discussion. For astrophysical projects, initial selection of objects for observation was the outstanding example of an SWG issue. Because irreparable damage to the observatory could occur at any time, the SWG had to decide which uses would leave the most important legacy in the event of early failure. Collective issues, though limited, could still be sufficiently important to prove taxing. For example, one project developed a system of sub-committees to the SWG to produce first cuts at trajectory and orientation issues prior to their consideration by the full SWG; yet a PI left this project partly out of an inability to elicit support for spacecraft orientations that favored the observations he wished to make.

The SWGs for the two projects that originated outside flight centers were the only SWGs in our sample that expanded their scope to include more than the collective issues created by the project's basic engineering. Because of the leadership of the scientist-instigators, the terms of their recruiting pitches, or the sense that scientists could choose their collaborators, the members of these SWGs were either more willing to put collective achievements on a par with individual achievements, or they were more insistent on controlling engineering judgements that could affect the instruments' capabilities. In one case [Einstein], the SWG oversaw integration of a unified science payload, which it then delivered to the flight center for assembly into the spacecraft. To insure that the participating scientists would take a constructive interest in one another's technical problems, they guaranteed each other limited rights to use one another's instruments and painstakingly negotiated among themselves a division of the scientific topics that each would initially address. In the other case [AMPTE], the SWG coordinated the operations of the several experiments at selected times and pooled the intercalibrated data streams in order to obtain as comprehensive a view as possible of important events. To insure that participating scientists had opportunities for individual successes, experiment builders also had ample time to run their individual experiments as each saw fit.

Even the self-organized projects that originated outside the flight centers never placed all areas of science activity within their SWGs' jurisdictions. Experiment builders almost always cared principally about the spacecraft's capabilities and their individual interfaces to it rather than the capabilities and designs of other experiments. Individual teams decided when and where to disseminate their findings, except when the projects arranged to have a special journal issue or conference session dedicated to the project. Individual teams decided the content of journal articles and conference talks. When scientists within a project reached different conclusions about the same topic, they almost always disseminated their views individually without attempting to reach an intra-project consensus.

B. The Scope of Flight Center Officials
[Table of Contents]
In every project, the flight center project manager was responsible for the project's money and schedule. That made the project manager the ultimate consumer of technical information from contractors, and usually the most powerful individual in the project during its design and construction. However, the precise scope of project managers' powers has been influenced by how far they were their involved in the formation of the project. Project managers were not officially designated until the agency was ready to commit funds for detailed design work (upon the project moving from Phase A to B); and in half of our cases, the project manager had not participated in the engineering studies that had established the project's feasibility and likely costs. When assuming management of projects whose scientists had already decided on the terms of their relationships, project managers have found their authority bounded by these pre-existing relationships.

Project managers who had participated in the early engineering studies usually imposed their flight center's customs for reporting requirements on the PIs and for the organization of flight center staff on the project. So did managers of projects whose scientists had not been on board from the outset. Because of accumulated traditions and experiences, the flight center customs were well understood by project managers and PIs[9], even when the PIs resented the flight center's culture or the project manager's style. Many issues were resolved in communiques between PIs or their engineers and the project manager or a flight center staff member the project manager assigned to track science payloads. (Such a staff member was variously titled "instruments manager" or "payload specialist.") To deal with remaining issues, the project manager almost always attended SWG meetings.

The effectiveness of this arrangement is evident both in the absence of hostile memories and in the recognition scientists occasionally gave to flight center staff members. In one of our cases [Voyager], where the project manager assigned separate staff members to track individual experiments, in at least two instances, experiment teams ended up making space on their teams for their liaisons. When PIs resented project managers' decisions over administration or over how to distribute mass, electric power, telemetry rights, or other limited resources, among the spacecraft systems, the PIs protested in ways that did not elevate the dispute to Headquarters, and ended up unhappily deferring to the project manager. One project manager recalled receiving an "earful" from the PIs about how cumbersome they had found the functional divisions into which the manager had divided the project. However, the PIs did not speak out at the peak of their difficulties but just before launch, when some of those divisions and the project manager himself were about to diminish in importance. In two separate projects [Voyager and Giotto], interviewees recalled the project manager ordering changes in an experiment's hardware. Even though the PI in one case felt the benefit of the change to the project manager was out of proportion with the difficulties imposed on the experiment team, in neither case was there any mention of discussion in the SWG or mediation by the project scientist[10].

Project managers had the most difficulty on the two projects that scientists outside flight centers had organized themselves, regardless of whether or not the scientists found the flight center's culture hospitable. In one case, the scientists expanded the SWG's scope to the integration of a total science payload, intruding on areas that were otherwise within the project manager's jurisdiction. The scientists deliberately excluded project management from some of their meetings, and flight center project staff felt misled on cost and progress of parts of the payload; scientists admit that to protect their autonomy they were less than forthcoming about problems. In the end, relations between scientists and project management were so poor that the scientists were unable to elicit the release of a marginal amount of money for hardware that could have significantly extended the life and productivity of the spacecraft. In the other project, the unity the scientists achieved by planning coordinated experiment operations enabled them to impose their will on the project manager. When a change in launch vehicle increased the mass the project could launch, the project manager would have preferred incremental increases to the payload, but the scientists rallied behind adding a fully instrumented sub-satellite that added complexity to the interfaces of the original mission. The project manager relented, but his relations with the principal scientists turned "polite but tense."

During mission design and construction, the needs of the project manager consistently determined the scope of the project scientist's work. When the SWG dealt with collective science issues within the planned boundaries of resources [ISEE and Giotto], the project manager needed the project scientist for guidance on when engineering expediency in design or construction could upset the scientists' planning. To keep control of the project, the project manager just had to avoid pushing the scientists to activate their independent access to headquarters officials. When the SWG incubated conflicting ambitions that the spacecraft could not handle [Voyager], the project manager needed the project scientist to adjudicate conflicts among the scientists and mediate between the scientists and project management. In these situations, a project scientist needed to be a trusted authority on the scientific merits of the several experiments. In the two cases when the scientists collectively enlarged the responsibilities of the SWG to intrude on the project manager's domain, they did so under the leadership of a lone PI who spoke for the collective science interest. In both these situations, the project manager's diminished powers led to a diminished role for the project scientist, because there were fewer matters on which the project manager needed a scientist's advice, and because the lone PI overshadowed the project science in stature within the project.

After the launch, project scientists administered project funds for data analyses and fielded proposals from members of science teams pursuing longer-term research on their data sets. Once funding for the project ceased, science teams had to obtain funding for analyses in the general competition for NASA program grants.

C. Coordination Among Flight Centers
[Table of Contents]
The cases we studied included three international, multi-flight center projects: two multi-spacecraft projects in which one spacecraft was built at each flight center, and one single-spacecraft project in which the flight centers each built part of the spacecraft. The multi-spacecraft projects were consciously organized to minimize inter-flight center engineering interfaces, to maximize the project managers' individual and collective latitude, and to leave coordination of the project's greater-than-national capabilities to post-launch operations. In one case [ISEE], the project managers maximized autonomy for the two centers by cultivating each other personally and paying careful attention to the interface between the spacecraft. In the other [AMPTE], more lower level contacts among the spacecraft engineers were relied on to achieve compatible spacecraft.

In both these projects, the SWG operated as an international body. In one, SWG meetings were held on both sides of the Atlantic with the host's project scientist chairing the meeting; in the other, the lone PIs for the spacecraft jointly chaired the meetings. In both cases, the SWG decided how and when to operate the spacecraft in a coordinated fashion.

The organizers were not able to divide labor so cleanly in the one-spacecraft project involving multiple flight centers. Two of the three participating centers built components whose design and interfaces directly affected each other[11]. This division enabled the project to take advantage of the centers' complementary strengths (one center had experimented with a new technology that was vital to one component but lacked the resources to build the related components, while the other center lacked experience in the new technology but had the larger staff and budget). Because the components had to be integrated, scheduling appears to have caused more stress in this project than others, both centers straining to avoid being a bottleneck to progress. Representatives of the two parties used frequent telephone calls, attended each other's design reviews, and stationed personnel at each other's shops to insure consistency in design. These practices worked; for example, one center successfully recommended a design change to the other's component in order to accommodate unexpected idiosyncracies in the first center's component. Ironically, this technical intimacy was followed by independent data-acquisition strategies. The centers divided responsibility for spacecraft operations by granting each blocks of time for its own use. However, scientists from each center have occasionally collaborated as individuals in order to create larger chunks of operating time than any could obtain on their own.

Differences in national forms of organization and culture have been apparent to interviewees in these projects, but they never proved a stumbling block to coordination. In two instances, European scientists rather than engineers served as project managers, but their American counterparts recounted no cultural obstacles to communication. In one instance, a European nation designated an original instigating scientist the "project director" in addition to designating a project manager and project scientist, but that reflected well-understood idiosyncracies in the formation of the project and never confused other collaborators about where to go for information.

Europeans have noted that NASA space flight centers, which have routinely assembled and integrated spacecraft, have larger staffs than either ESTEC (which always has contracted out spacecraft construction) or the European research institutes (which have infrequently built spacecraft). Some have noted—sometimes in admiration and sometimes in frustration—that American flight centers seemed to respond to difficulties by holding open brainstorming sessions that drew in their large staffs with their varied specialties, rather than adding a few more people to the project.

Undoubtedly the most significant organizational differences are the obvious ones: ESTEC project managers have never controlled the funding for experiments while NASA project managers have; and ESTEC project scientists have never been PIs while NASA project scientists have. How one could document any effects of this difference is unclear. Perhaps ESTEC project managers have felt broader license to impose technical burdens on PIs, because the managers do not have to fund the work to meet those burdens and because project scientists, not being PIs, lack the status to oppose them.

D. The Scope of NASA Headquarters Officials
[Table of Contents]
Once Headquarters had selected a flight center, selected the PIs, and initiated the flow of money for a project, its officials lost most, but not all ability to exert daily influence over a project. Whether they continued to be active in a project depended on the project's budget and the intensity of conflict between scientists and project management. When a project was expensive for its time, or when conflict within the project was sufficiently intense, Headquarters officials were influential.

Project managers always wanted headquarters program managers to limit themselves to handling the project's external relations with the rest of Headquarters and the political institutions that oversee the agency. In order not to excite suspicions that projects harbored hidden problems, project managers routinely invited program managers to project staff meetings. This tactic worked for conflict-free projects that were part of the low-budget Explorer program. To both scientists and engineers in these projects, it was flight center administrators who were the powerful officials to worry about in the event of technical problems.

In the two projects that were too expensive for the Explorer program, headquarters program managers were more active. In one case, the program manager accepted invitations to design meetings and, to the dismay of the project manager, argued technical points with the project manager and participating scientists. In the other case, the program manager telephoned the project manager so frequently that the program manager felt all major issues were resolved verbally before plans were committed to writing. Neither of these program managers managed one of the Explorer projects we studied, so we have no evidence on whether their activism was a function of project costs or personal styles. But we would guess that when projects have been expensive enough to attract political attention, program managers, who must represent their projects to higher authorities, have needed to participate in project decision-making in order to feel comfortable with their duties.

Program scientists always became significant when participating scientists and project managers could not resolve their conflicts. In our cases, such conflicts only occurred in projects that originated outside the flight centers. In one case [AMPTE], the program scientist had been the headquarters scientist who had supported the scientists' ambitions to form a project. He helped the scientists obtain permission to attempt centralized processing of data, even though the project manager doubted the feasibility of the operation within the project's schedule and budget. In the other case [Einstein], the program scientist had assumed his duties well after the project had been formed and did not wish to see a tradition of self-formed projects become established. When the scientists took to Headquarters their dispute with the project manager over spending additional modest money for mission-extending hardware, they were denied the funds.

IV. ACTIVITIES OF EXPERIMENT TEAMS
[Table of Contents]
"Experiment" in the terminology of space science has referred to the design, construction and operation of an instrument plus processing and interpreting the signals the instrument returns. For purposes of design and construction, an instrument was often broken down into self-contained "boxes," whose mechanical interfaces were cleanly and simply specified at the start of the project and whose digital interfaces could be worked out over the course of construction. In this section, we will use "principal investigator" (PI) to mean the scientist in charge of an experiment, whether or not that was the title used in the project. Other team members with independent standing as scientists usually held the title "co-investigator." The significance of that title, as will be seen, has varied.

A. Origin of Space Experiments
[Table of Contents]
Space-based experimentation has involved many intrinsic technical difficulties not encountered in laboratory work. Instrumentation has had to be light enough to reach its destination on the rockets of the day and mechanically strong enough to survive the vibrations of launch; it has had to operate on the electrical power the spacecraft has provided, keep operating without hardware repairs for a worthy amount of time amidst the environmental hazards of space, and read out electronically so that collected data can be telemetered back to Earth. Experimentalists in space science have routinely employed two strategies for coping with these technical facts of life. First, they have specialized in the design and construction of particular types of instrumentation; once they have been able to "space qualify" an instrument, rarely, if ever, do they even consider diversifying into a new area of instrumentation because of the competition they would face from established specialists. Second, they have relied on commercially available components and industrial expertise in building their instruments. Because many of their technical problems—e.g., detecting faint radiation signals and reducing the weight of equipment—have been generically equivalent to the military's technical problems, space scientists have often been able to adopt or adapt what commercial manufacturers have researched and developed for military use.

Of 27 experiments for which one or more interviewees addressed the relationship of an instrument to earlier work, 23 were described as updated or modified versions of what the PIs or their mentors had flown on a previous mission or designed for a previous mission. One experimenter spoke for many in pointing out that while the basic design of his instruments has remained constant, the detector elements and logic circuits he buys keep getting better. With better detector elements, experimenters obtain information on broader, more continuous bands of radiation frequencies or particle energies. With better logic circuits experimenters can operate their instruments in more modes and obtain more information from their allotted telemetry. Experimenters also occasionally pointed to the availability of exceptionally lightweight materials as essential to making an older design viable in a new mission.

The military context in which the parts and materials of space instrumentation originated has not noticeably hindered space scientists. In only one instance did an interviewee need a low-level security clearance to work with a component. Even with the clearance, he felt he lacked ready access to the information needed to understand the part's internal workings; however, instead of handicapping his work, the restrictions may have helped him to discover that the component could be reliably used without knowing precisely how it worked. In all other instances, space experimenters simply began buying components as their manufacturers obtained clearance to market them, or experimenters contracted with the firms the military used in order to acquire materials or components.

In the rare instances when space scientists attempted to develop technical novelties, they still did not consider the new device suitable to incorporate into a space mission unless an industrial firm took up its manufacture. Even then, difficulties in manufacturing a device could discourage a firm or cause a loss of confidence among other participants in the project. Such problems were cause for helpful intervention by a flight center, which recognized that the viability of a science program depended on commercial suppliers of specialized components.

Scientists interested in carving out a niche for themselves in space experimentation consciously looked for laboratory set-ups they thought could be adapted for use in space. The experiments covered in our cases included three claims of "space firsts" (at least for unmanned space missions)[12] for a particular instrumental technique and one instance where a team sought to create an order-of-magnitude improvement on what another team had previously flown. Three of these four cases nearly ended in disaster. In one case the PI did not realize that some part of his instrument was outgassing material that could distort readings until the instrument was being integrated into the spacecraft; the PI had no chance to change the hardware but fortuitously found a way to minimize the effect. In another case, flight center officials considered mothballing the project because an experiment team's contractor could not manufacture components that equalled the performance of the team's prototype; eventually the contractor was replaced and the project stayed close enough to schedule by using the prototype for testing and integration with the rest of the spacecraft. In a third case, the inexperienced team was so late in delivering the instrument that it was not calibrated as carefully as planned and its effects on other instruments were not checked as fully as other PIs desired; the scientists learned post-launch how to assess and compensate for their effects on each other. Such anecdotes suggest why space experimentalists work within an instrumentation niche rather than venture frequently into new technical areas.

B. Organization of Experiment Teams
[Table of Contents]
Experiment teams have usually had a center-periphery structure. At the center has been a small number of institutions—sometimes just one—overseeing hardware development and basic data-processing software. On the periphery have been several co-investigators, often from other institutions, providing additional expertise in the science analysis of the data. In this manner, work on the many technical problems of space-based instrumentation have been efficiently centralized without shutting out scientists with lesser instrumentation skills or resources, and without wasting data on experimentalists unaware of all the ways the data could be used.

In the projects that were entirely managed in NASA flight centers, one institution almost always oversaw the development of each instrument. PIs struggling to adapt a laboratory instrument for space use sometimes elicited help from the original laboratory developers on an ad hoc basis. Co-investigators never influenced the technical development of an experiment; they were chiefly of symbolic importance, demonstrating the existence of outsiders' confidence in the scientific value of a proposed experiment. In one case, a postdoctoral scientist consciously shifted from a co-investigator's to the PI's institution in search of technical intimacy with the instrument; the postdoc recalled that the PI unilaterally decided to use recently developed detector components that had been discussed only in the proposal's appendix. In another case, co-investigators who had been added to a team at the insistence of NASA Headquarters were unable to budge the PI from building an instrument that was higher in sensitivity and lower in resolution than seemed appropriate for the bulk of the mission.

By contrast, interviewees from more than half of the experiment teams on international projects (whether between NASA and ESA, NASA and the space agencies of individual European nations, or among European nations contributing to an ESA project) reported that their teams divided responsibilities for the development of each individual instrument among institutions from different nations. The leading scientists from each institution had to agree on who among them would be the PI. Often political expediency made one scientist the obvious choice—e.g., an experiment team consisting of an American and European institution would shift the title and duties of PI depending on whose agency was soliciting proposals for the kind of instrument the team made. The other scientists whose institutions would contribute part of the experiment were designated co-investigators. Thus the term "co-investigator" was ambiguous in these missions; it could refer to scientists who contributed part of the instrument or to scientists who boosted the experiment's scientific breadth and credibility but were marginal to the experiment's design and construction.

In experiments with multi-institutional contributions to design and construction, the PI had to decide on the allocation of the experiment's spacecraft resources among the instrument's components and was responsible for keeping the several parts compatible. PIs varied temperamentally in whether they preferred to build consensus or make quick personal decisions over allocation issues. In many cases, the institutions of an experiment team had previously worked together, trusted each other, and built the experiment out of self-contained boxes that interfaced digitally but with minimal mechanical complexity. Even the scientists that were working together for the first time reported nothing particularly taxing in their social arrangements (with one exception, in which the PI was a technically inexperienced theorist whose administrative superior was unsympathetic to his experiment). The overwhelming judgment among scientists in multi-national experiment teams was that the benefits of dividing costs across governments and dividing labor among institutions with complementary strengths far outweighed the extra time and money spent insuring that independently built parts would work well together.

C. Organization of Data Acquisition and Analysis
[Table of Contents]
In all the cases we studied, the engineering of the mission forced participating scientists to work out a more or less elaborate policy for acquiring data. In two cases [IUE and Einstein], instruments could only be used in series and a schedule had to be worked out; in two others [ISEE and AMPTE], the operations of multiple spacecraft and at least some of their experiments needed to be coordinated; in another [Giotto], telemetry formats and spacecraft trajectory needed to be adjusted to suit particular experiments at particular times; in another [Voyager], several instruments were mechanically constrained to operate in unison and a schedule had to be worked out. In all but the last case, experiment teams were unified in their desires and data-acquisition strategies were set in the SWG. In the last case, experiment teams included co-investigators with diverse scientific interests and conflicting data-acquisition strategies. Initially, the PIs were obliged to represent their teams and to learn where divisions in one team coincided with those in another. But over time the project formed cross-team interest groups to discuss how best to share data-acquisition capabilities, and the SWG only dealt with conflicts that the interest groups did not resolve.

Once data were collected, experiments and projects differed in the extent to which they processed and distributed their data. At one extreme were two projects [IUE and Einstein] that standardized processing with the goal of creating data that outside users could confidently analyze and interpret. At the other extreme were two projects [Voyager and especially Giotto] in which each PI controlled a team's data with minimal contractual requirements, few intellectual benefits, and even fewer social incentives to prepare the data for distribution outside the team. Towards the first extreme was one project [AMPTE] that eliminated proprietary rights to data within the project by processing data streams in parallel for collective consideration. Towards the second extreme was a project [ISEE] that required experimenters to distribute their "rough numbers" within the project with the understanding that anyone intrigued by something in another's data would check with the relevant PI before proceeding towards publication.

The three projects that treated data as relatively public property included the two that formed outside flight center auspices. The scientists' ambitions in these community-reforming or community-creating projects required, in the first case, that they collectively document the phenomena they believed should attract attention, and in the second case, that they enable many scientists to convince themselves of the utility of the project's family of techniques. The community-affirming projects that formed within the flight centers usually aggregated scientists' individual ambitions for improved measurements of phenomena of known interest. In these cases, project scientists took a laissez-faire stance towards how PIs shared their data.

Data collectors usually had formal proprietary rights to their data for a defined period (usually one year) and then had to turn over the data to an archive. Still, PIs were often treated by other scientists as the owner of the data for considerably longer periods. (In the projects with standardized processing, data collectors were often not PIs, in the sense of experiment builders, and were less likely to be viewed as owners of archived data.)

Typically, PIs made their experiments' data fully available to all their co-investigators. In the few cases where PIs were hard pressed to produce the hardware or basic data processing software, they thought their co-investigators were better positioned than themselves to take the lead in producing science analyses. Teams varied in whether they regulated who worked on particular topics that could be addressed through the data. Europeans seemed more prone to implement a division of topics.

The overwhelming consensus of interviewees was that experiment teams have striven for, and occasionally achieved, self-sufficiency in their ability to perform scientific analyses. Some see this condition as driven by career and political structures—experimenters need distinctive results to justify the public support they received and to stand out in the competition to participate in future projects. Others see self-sufficiency as driven by technical and cognitive realities—the amount of work an experimenter invests in building an instrument and processing its data into meaningful physical units precludes working with others' data. But in general, projects left PIs to dispose of their data during proprietary periods, and provided neither technical nor moral supports nor impediments to inter-team data sharing or analyses.

Experiment teams, however, were frequently unable to achieve the ideal of scientific independence. In most cases, teams found their way more or less easily to exchanges of processed data, with the understanding that borrowing scientists would have the lending PI check the borrower's work before the borrower disseminated results based on the loaned data. Such exchanges were more easily reached when, for example, members of two teams felt equally dependent on one another; when a borrower's scientific interests required a less refined version of the lender's data than the lender wished to work on; and when a PI owed his spot on the spacecraft to other scientists' success at expanding the payload.

The ease with which errors can slip into data analyses and the importance of having a PI check a borrower's work was stressed by several interviewees. Two of them reported instances in which their mistakes in the use of data were caught by a PI or an instrument operator. One member of an experiment team reported publishing an erroneous analysis of the team's data because of a failure to recognize that a recalibration of the instrument did not leave the instrument trustworthy in all ranges of interest. A member of a different team reported that outside scientists interested in the team's data had the original team process the data for the outsiders rather than work from archived data.

In a few instances, experimenters did become interested in each other's raw data. In one project that originated outside the flight centers [AMPTE], experimenters committed themselves, for particular periods, to collective assessments of their data streams, and consequently had to inter-calibrate their instruments. Such an arrangement was so rare and the confidence of the several PIs in their instruments was so high that one experimenter joked that the project violated "a rule of experimental physics that you should never measure anything more than once, because if you do, you'll get two different answers—and we quite deliberately had overlaps." Differences among the instruments' readings were narrow enough and relationships among the experimenters strong enough that the feared disputation over whose experiment was truly reliable never materialized. By contrast, in a project that originated within a flight center [Giotto], a team took to digitizing the published data of another in order to be able to work with both teams' data. In only one instance, involving a project with standardized data processing, did researchers reprocess raw data from an instrument they had not built. When they used their programs not only on the data and topics they were initially granted as co-investigators, but later on data and topics their collaborators had worked on, their work spawned an intense, open scientific controversy over the quality and interpretation of the two groups' findings.

D. Dissemination of Results
[Table of Contents]
The title "principal investigator" conveys responsibility for the quality and publication of data. In the four projects in which multiple PIs built their own instruments or took their own observations, the PIs judged the content of their teams' publications independently of each other and decided on the time and place of journal submissions. (An exception to this generalization has been the journal issue dedicated to a project's results; in these cases, the project determined time and place of submissions, but the PIs still independently assessed their teams' contributions.) In the two with single PIs, only once did any participating scientist report that a PI tried to use the titular position to demand the right to approve a paper before publication. The participating scientist felt he secured his rightful freedom to publish after threatening to publicize their argument.

Experiment teams in space science have involved few enough scientists that they have not needed formal procedures to regulate the production of scientific papers. Fear of errors in analysis and common courtesy have insured that when writers work with more than one data set, they elicit and recognize contributions from within their team and from other teams. Tolerance of open differences in interpretation of data have allowed writers to publish papers without achieving consensus among all scientists who contributed to the data[13].

V. FUNDING OF SPACE SCIENCE
[Table of Contents]
In the United States, NASA has been the sole supporter of space science. NASA's Office of Space Science (and Applications) gives this in two ways: through grants programs, which discipline scientists use to support analyses of extant data and to support research and development into instruments for taking data, and through contract programs, which program managers use to support the construction of spacecraft and their payloads of scientific instruments. In Europe, the several nations have their individual means for supporting research and development. ESA's Science Directorate has contract programs to support construction of spacecraft for science projects. In both cases, the separation of support for research and development into instrumentation from the support of instrument construction for space projects has encouraged technical specialization and conservatism in projects. With their nations' support for instrument research and development, PIs have been expected to figure out how to "space-qualify" an instrument that could outperform predecessors or measure new parameters. Only then could they reasonably hope for success with a proposal to build an appropriately tailored version for a particular project.

The scientists and engineers who eventually absorbed project funds were rarely privy to decisions that compared the value of science projects serving different areas of science, and none of those we interviewed spoke of any involvement in comparisons of the value of science to other space activities. Project instigators were active in the politics of funding at the level of addressing panels and working groups, whether organized by a national academy or a space agency, in the hopes of establishing that their projects best advanced their field of science. Once that groundwork had been laid, even the best connected of project instigators appear to have been excluded from higher policy discussions. In NASA Headquarters, "branch chiefs" or "discipline scientists" (the title has changed over time) pass their recommendations upward to division chiefs, who cover broader areas of science. Division chiefs report to the Associate Administrator for Science. Each individual in the chain has a working group of scientists to help consider programmatic possibilities; these groups are apparently becoming generators of ideas and plans as well as reviewers of the ideas and plans of others.

A relatively expensive project will be funded only if it is part of a program that has won a dedicated line item in the political negotiations over the NASA budget. Otherwise, a project must be inexpensive enough to fit into the Explorer Program[14]. Project instigators have so badly wanted to fit into the Explorer Program, in order not to have to face the uncertainties of higher political reviews, that they have knowingly resorted to dubious accounting practices. Inclusion in the Explorer Program did, however, come at the cost of ongoing competition with other Explorer projects for the funds that Congress appropriated in any given year.

The ESA Science Directorate has resembled an enlarged Explorer Program. With its budget set on a five-year basis, the ESA Science Directorate does not face a political hurdle equivalent to acquiring a new budget line every time space scientists unite behind a major project. European scientists' and engineers' ideas for projects are reviewed by an astronomy or solar system working group. Surviving plans go to the Space Science Advisory Committee, whose findings are rarely reversed by ESA's Science Policy Committee, a decision-making body that has included a representative from each member nation. As with projects in NASA's Explorer Program, ESA's projects influenced one another's schedules and budgets.

The funding patterns and accountability systems of NASA and ESA have diverged after a project manager has been appointed. Depending on the demands of the project and the supply of resources at the flight center, NASA project managers have had the option of contracting out construction and integration of the spacecraft to an aerospace firm or directly overseeing assembly and integration in-house. ESA project managers have always had to contract out for spacecraft construction and integration. The NASA project manager's budget has had funds for construction of both the spacecraft and its payload of scientific instruments (though occasionally another US government agency or a foreign nation has contributed funds for part of the science payload). The ESA project manager's budget has had funds only for construction of the spacecraft; scientists building instruments for the payload have obtained their funds from their national governments. European scientists, even from the same nation, differed on the severity of the national reviews for the funding of experiments: some thought the review pro-forma given ESA's endorsement of the experiment; others prepared carefully for the review to show respect for national administrators and to guard against any unexpected squeezes on national funds; and some considered the review a major hurdle given the nation's scientific traditions and priorities.

A two-by-two matrix can be constructed for accountability relationships in space projects. Project managers can both oversee construction in-house and manage funds for scientific instruments; or they can build in-house and not fully control instrument funding; or they can build out-of-house and control instrument funding; or they can build out-of-house and not control instrument funding. ESA project managers always fell in the fourth category, and NASA project managers predominantly fell in the first or third. But some NASA project managers have also had a foot in the second or fourth categories when one or more of a project's experiments came from European scientists or from American scientists with non-NASA funding. In practice, none of the NASA projects we studied put project managers entirely in the fourth category.

Whenever project managers had the spacecraft built out-of-house, they wanted communication between scientists and the prime contractor to flow through them. Managers feared that unregulated technical discussions between scientists and contractor personnel could undermine their control of budget and schedule by spawning plans or expectations among people over whom they lacked authority. The fourth-category ESA projects have probably been the most structurally contentious, since the project manager and PIs have drawn their funds from different sources and thus have no direct incentive for keeping each other's costs down. In the case we studied [Giotto], the project manager did impose noteworthy technical burdens on some experiments and prevented back-channel communication between experimenters and spacecraft builders. But the project that seems to have induced the most enduring bitterness involved a third-category NASA project in which scientists struck a deal with the spacecraft builder for extra hardware, only to see the project manager refuse to allocate the funds.

Projects in which the project manager both oversaw assembly in-house and managed the funding of experiments had the least structural conflict. Scientists had less to gain from back-channel communication with a contractor that was providing a particular spacecraft component than from a contractor building the entire spacecraft. Project managers had less to gain from insisting that scientists meet more stringent engineering requirements because the project managers had to fund the extra work involved.

VI. INTERNATIONALISM IN SPACE SCIENCE
[Table of Contents]
Space science has been international at two levels. Projects have combined the efforts of flight centers and scientists in multiple nations. And experiments have been built by multi-national teams of scientists and engineers. Most interestingly, only multi-national experiments, not projects, have been a crucible for the creation of enduring working relationships.

A. Internationalism in Projects
[Table of Contents]
Including the ESA project, which was intrinsically international, four of the six projects we studied were organized on a multi-national basis. Four forces were responsible for making projects international: the desire to combine technical specialties that had become better developed in different nations; the desire to broaden the base of scientists competing to participate in a project; the desire to spread the costs of a project across governments; and the desire to use a quasi-diplomatic agreement to make projects more difficult to cancel. No single force entirely justified the internationalization of any individual project, but different forces were more important in different types of projects.

Two of the four international projects we studied were community-affirming and formed with the active support of flight centers. In both these cases, broadening the scientific base and increasing the commitments of governments were the predominant forces for internationalization. In a NASA-ESA project [ISEE], a European scientist recalled that Europeans and Americans had been independently contemplating similar two-satellite missions. When they became aware of each other's thinking, they saw obvious benefits in cooperating as equals with each agency building one spacecraft: a better scientific payload could be formed from an international competition for instrumentation slots; and the international agreement would make the project less vulnerable to cutbacks in case NASA encountered budgetary pressures. In an ESA project [Giotto], a core of largely German instigators felt they needed more prospective participants from other nations to boost the project's viability within ESA's political structure. The campaign to broaden international participation netted worthy proposals for instruments than had not been in the straw-man payload and significantly increased the project's scientific breadth.

The desirability of spreading costs across governments and of coordinating technical specialties better developed in different nations were relatively unimportant in international, community-affirming projects. The NASA-ESA mission was pursued under the Explorer program on the NASA side; its American advocates may have preferred to keep their needs within the Explorer umbrella, but they could have aimed for an entirely national program with its own line in the NASA budget. The project manager of the ESA mission felt secure enough with the budget to reject a NASA offer of operations and launch support in exchange for a guaranteed spot for an American experiment in the payload. In both of these projects, the participating scientists designed their experiments as independently from one another as spacecraft engineering realities allowed. While agency headquarters selected experiments that complemented one another, neither headquarters nor flight center officials tried to coordinate the PIs' efforts to analyze their data and disseminate their findings.

By contrast, an international community-reforming project [AMPTE] and an international project that bordered on community-creating [IUE] became international primarily to coordinate expertise that was unevenly spread among nations. The former project used research institutes of different nations to build multiple spacecraft to serve complementary functions that the collaboration coordinated in operations. The latter used one nation to build the bulk of the science payload, but delegated responsibility for the most innovative component to another nation, because the other nation had pioneered in developing a technique essential to the component. These two projects were not immune to the other forces of internationalization. One seized on an upgrade in launch capabilities to broaden its scientific capabilities by bringing in a third nation to instrument what had originally been an inert part of the spacecraft. The other spread funding burdens across more contributors by offering responsibility for a spacecraft system that was easily isolated from the science payload to a third flight center. However, in both cases the instigating institutions fit the additional participants into a scheme the instigators had already set. The initial thrust to internationalize lay in the instigators' inability to assemble the needed expertise on a national basis for projects designed to stretch the social fabric of scientific sub-communities.

Mundane logistical difficulties of meeting and communicating accompanied the internationalization of all these projects, but more serious difficulties were concentrated in the projects that had to coordinate expertise. Most important were managerial stresses stemming from the different policies of different space agencies or from the independence of the flight centers. The project coordinating multiple spacecraft that performed different functions [AMPTE] needed to pool data streams to get the benefits of the coordination. American scientists could readily accommodate this as an incremental change, for they were accustomed to NASA requirements that they archive their data. But the European scientist-instigators faced a difficult selling job, for European scientists were accustomed to controlling the use of their data without regulation from ESA (which had no authority over data because it did not fund the experiments). The project that built closely linked components of the scientific payload in different flight centers [IUE] could not shift personnel across national borders in response to problems; the result was probably some extra expense, as people on one side were paid to wait for the other's work, and there were some prickly feelings about who delayed whom.

All of these projects overcame difficulties rooted in their internationalism, and most interviewees spoke warmly of their interactions with colleagues of different nationalities. However, in only one of our cases was there any prior history of collaboration among any combination of the project scientists, project managers, scientist-instigators, or PIs, and nobody spoke of ongoing interests in developing future joint projects with their prior collaborators. International projects, while necessary and desirable, apparently exhausted their participants.

Numerous interviewees noted a recent loss of effectiveness of international agreements as a tactic for securing a project's place in NASA's budget. They usually identified the annual political review of NASA's budget, in contrast to ESA's five-year budget cycle, as the cause of NASA's problems in keeping multi-year commitments to international projects.

The frustrations of Europeans with NASA was somewhat tempered by the realization that the NASA funding structure has favored Europeans over Americans in the competition to fly experiments. Because NASA has funded both experiments and spacecraft construction, NASA could reduce its fiscal burden for a project by accepting a European experiment, which would be funded by the scientists' national government(s). ESA, however, has only funded spacecraft construction; therefore, it has had no fiscal incentive to accept American experiments. A NASA administrator, who decided to drop a European experiment as the scientifically least indispensable part of a payload that was outstripping the spacecraft's weight and power resources, recalled the decision was difficult because it did not ease the project's budgetary pressures on NASA.

B. Internationalism in Experiments
[Table of Contents]
Five of the six projects we studied in space science had formal international collaborators on one or more experiment or user teams. While we lack data from which to measure the prevalence of internationalism over time, the qualitative impression of interviewees is that social and technical forces are encouraging the internationalization of experiment teams.

Internationalization on the experiment level, as on the project level, had obvious fiscal and political advantages. Interviewees often cited spreading the costs of an experiment across governments as a virtue in the eyes of the funding agencies. International experiment or user teams that divided responsibilities with rough equality could use political expediency to determine which member served as PI for a proposal. In trans-Atlantic projects, an American scientist would typically be PI on a proposal to NASA and a European on a proposal to ESA. For an ESA project, international experiment teams would put forward as PI a citizen of a nation that was expected to generate relatively few proposals, because ESA's Science Policy Committee was presumed to be sensitive to the distribution of PIs among nations. However, when one nation's institutions absorbed most hardware responsibilities, the designation of another nation's scientist as PI for the experiment could be interpreted as an act of political chicanery; participants in one project did view one proposal (which was rejected) as such an instance. The national funding of experiments for ESA projects also motivated Europeans to internationalize experiment teams in order to guard PIs from funding problems. In two instances, PIs felt their international collaborators saved their experiments by coming up with resources to trouble-shoot unexpected technical problems that the PIs' national governments and home institutions were not prepared to cover.

Unlike at the project level, where internationalism sometimes consisted of coordinating the operations of independently built spacecraft, at the experiment level, the fiscal and political benefits of internationalism were available only to teams that divided among nations the technical labor for design and construction of single instruments. It is testament to the power of internationalism's advantages at the experiment level that international experiment teams treated interface and integration problems as challenges to technical cleverness. Even the administrative burdens of strict adherence to export- and technology-control regulations were an acceptable price for the benefits of internationally dividing hardware responsibilities.

Scientists who only analyzed data, and who were not citizens of the PI's nation, did not bring the political and fiscal benefits of internationalism. When contributors to an experiment's instrumentation wanted additional co-investigators to do data analyses for topics that were outside their interest or expertise, they usually found domestic collaborators. In one of the few instances where a European scientist was added to analyze the data of an American experiment team, his colleagues appreciated his aggressive pursuit of topics they were not covering, but also found he brought a penchant for redoing work in order to have his own nation's version of the data. Only when teams faced stiff competition for a slot on a spacecraft did they recruit foreign scientists with high prestige or rare expertise to boost the credibility of their proposals. Otherwise, experiment teams preferred not to avoid the risk of nationalist tensions within team dynamics.

VII. SPACE SCIENCE CAREERS AND SPACE SCIENCE PROJECTS
[Table of Contents]
Space-based research has been a risky foundation for a scientific career because of a combination of two factors. First, space-based data acquisition has been beset with problems beyond scientists' control—launch failure, spacecraft problems, or unlucky encounters between instruments and meteors or cosmic rays. Second, space scientists have not comprised a discipline unto themselves; American scientists who depend on space-based instrumentation to provide data join such societies as the American Physical Society, the American Astronomical Society, or the American Geophysical Union but have never formed something comparable around space science. Consequently, they must compete in these disciplines with ground-based observers and laboratory experimenters with more secure sources of data. Space scientists' careers have been based on the presumption that the quantity and quality of scientific papers that can be written on the basis of a successful space-based experiment justify the risk of total failure.

Intensifying the high-risk character of space science careers is the impression of virtually all interviewees that the length of time needed to prepare space projects for launch has been increasing and the number of flight opportunities has been decreasing. Although the greater length in project durations is assumed to be accompanied by larger project budgets and science payloads, the extra money and instrument slots, interviewees believe, not only fail to compensate for the smaller number of flights but also add unwelcome administrative burdens and political interest in the disbursement of research funds. Some scientists advocate and practice a reconsideration of their institutions' roles in the creation of future space scientists.

The greater difficulty of pursuing space science is predictably lamented by instrument designers, especially those based at universities. They believe that graduate students find participation in space-based hardware projects to be too long and risky a route to an advanced degree in comparison to other possibilities. Of the graduate students we interviewed, only one had tried to pursue a hardware project, which personal circumstances forced him to drop, and he, like the other students we interviewed, launched his career on his ability to extract important measurements from data generated by instruments he had not helped to build. Some instrument designers also felt a lack of academic recognition for their activities. One in particular wonders whether his academic career was slowed because as a postdoctoral scientist he was consumed by hardware problems while working for a PI, when he could have better kept up with the literature, assumed some academic responsibilities, and still had access to the data (though less technical sophistication in analyzing them) while working for one of the PI's co-investigators. Another scientist found that his work on project hardware qualified him mainly for industrial positions he did not want or for another post in a generically similar project. He characterizes scientists as playing "chicken" with each other—keeping the rewards for instrumentation development low and assuming "that somebody's going to be foolish enough to spend some time building something for the sake of the community."

By contrast, scientists who have participated in a project but not had direct responsibility for instrumentation have happily prospered in academic