Construction of the International Space Station (ISS), under development since the late 1980s, began with the launch of its first element in November 1998 and is ongoing. In the spring of 2001, the National Aeronautics and Space Administration (NASA) announced that it would make major changes in the final configuration of the ISS in order to address serious construction cost overruns. The new ISS configuration is referred to by NASA as “Core Complete”; the earlier configuration was based on NASA’s Rev. F design documentation. Some decisions regarding the new configuration are yet to be finalized, but the changes from Rev. F currently include the deletion of a crew return vehicle, which will force a reduction in the number of ISS crew from six or seven to three; the deletion of a number of the major science facilities planned for the ISS; and a reduction in the number of annual shuttle flights to the ISS. Serious concerns have arisen within the science community and elsewhere that these changes would jeopardize the ability of the ISS to support the world-class science that has often been cited as its primary purpose. This report examines the factors, including ISS design changes, that limit the ability of the science community to utilize the ISS for research and makes recommendations for maximizing the ISS’s research potential.
IMPACT OF CORE COMPLETE DESIGN ON RESEARCH
The task group reviewed individually most of the principal areas of science that were intended to be supported on the ISS and considered the impact that the design changes would have on each. The level and type of impact resulting from the design changes in the ISS vary considerably from discipline to discipline. The physical sciences received the majority of the cuts made in facilities and equipment for experiments. Two of the three materials science research racks planned for the ISS were canceled, along with all but two of the experiment modules for the remaining materials facility. More than half of the planned materials investigations on the ISS were deselected, and the scope of work for those that remain has been reduced dramatically. One of the two facilities supporting fluids research (it was also intended to support combustion research) was canceled, along with a number of experiment modules. About 28 percent of the planned fluid physics experiments have been canceled so far, with the remaining experiments now expected to fly in 2005-2008 if funds become available for the development of the experiment modules. The only remaining facility for combustion research was canceled and then reinstated, but its future remains uncertain. The stowage space for combustion research was reduced by half and its allocation of crew time by 70 percent. The result is that each set of combustion experiments has been replanned and will be constrained to fewer tests over a smaller range of conditions, thus reducing their scientific value.
Fewer cuts were made in the equipment needed for research in bioastronautics, but the lengthy delay in availability of the centrifuge and the delay or cancellation of animal habitats will prevent research on the animal models needed to study radiation effects and bone and muscle loss until those facilities can be built and installed. Cell science and biotechnology research, which includes research on bone and muscle cells, will now be limited to two EXPRESS racks instead of six. The reduction in crew size will reduce by at least half the number of subjects from which critical data on human physiology and behavior can be collected, thus doubling the number of years needed to obtain a statistically significant data set. In areas such as plant biology and radiation studies, considerable specialized training is needed to perform experiments, and this training is far less likely to occur with a smaller crew. In fundamental biology many experiments are labor-intensive, and the reduction in crew time is expected to critically compromise experiments in this area.
While some research areas are more severely affected than others by the changes, clearly NASA’s revision of the ISS to the Core Complete configuration has drastically reduced the overall ability of the ISS to support science. The reduction, singly or in combination, of upmass capability, research facilities and equipment, and available crew time for science activities severely limits or forecloses the scientific community’s ability to maximize the research potential of the ISS. Moreover, the absence of any overarching, well-articulated goal on which to base scientific priorities that would unify or guide the downsizing process has further exacerbated the already significantly diminished capability of the ISS. The impact on the various scientific disciplines of revising the ISS to the Core Complete configuration varies but in all cases is substantial. Although NASA’s stated goal for its ISS program is to create a world-class laboratory, it is the opinion of the task group that the actions taken with regard to crew time, equipment, facilities, and logistics make this unlikely. Specifically, the task group found the following to be the most significant factors limiting the ability of the science community to maximize the research potential of the ISS:
Interdisciplinary priorities not in place. Decisions to cancel or greatly delay experimental facilities and equipment vital to specific scientific disciplines were made in the absence of cross-disciplinary priorities to guide the selection process. In many cases these decisions were made based primarily on what equipment had not yet been built, without any apparent weighting of the impact on overall scientific objectives.
Crew time. The most widespread and significant impact of ISS design revisions on the achievement of scientific objectives stems from the more than 85 percent reduction in crew time available for scientific activities.1 This limitation has an impact on every discipline examined, ranging from a potential total elimination of the ability to achieve even a modicum of meaningful work on the ISS in the areas of radiation biology, systems physiology, crew behavior and performance, and fundamental biology, to lesser impacts on disciplines such as plant science, materials science, fundamental physics, combustion science, and fluid physics. Even these potentially less seriously affected fields will probably sustain significant negative impacts when they are forced to compete with the remaining scientific complement for the minimal time available.
International partner participation. ISS partners will also experience major reductions in their ability to perform science on the ISS as a result of the Core Complete design. As a result, serious questions have been raised about whether international partners will continue to support ISS development at originally planned levels. Such reductions could seriously reduce the remaining science capabilities of the ISS since the international partners are responsible for elements critical to many U.S. investigators. Loss of the Japanese experiment module exposed facility, for example, would all but eliminate research in fundamental physics.
Science facilities and equipment. Many U.S. experiment racks have been eliminated or delayed indefinitely in the redesign of the ISS. In addition, the modules containing the functional equipment that goes into the remaining racks have also been reduced significantly in number, worsening an already dramatically reduced capability. The scientific disciplines affected most severely by these reductions are materials science, fluid physics, fundamental biology, and muscle and bone physiology.
Shuttle upmass capacity. The upmass and stowage volumes for many of the experiments are expected to be severely curtailed as a result of the reduction in shuttle flights and facility changes in Core Complete, and the quantity of scientific work is expected to be reduced accordingly. In fact, the constraints of meeting ISS operational needs with only four shuttle flights per year is expected to leave
very little shuttle volume for ferrying supplies and equipment to experiments on orbit or for returning samples to the ground.
Research community readiness. The factors cited above, when combined with the poor track record of NASA and the ISS in meeting schedule, budget, and scientific performance targets, further detract from the ability of the ISS to garner the support of the scientific community. The uncertainty and instability in the ISS program are disincentives to participation by both established and next-generation scientists, whose careers can be seriously damaged by the failure of the ISS program to provide the promised scientific opportunities.
MAXIMIZING RESEARCH POTENTIAL
In considering ways in which the research potential of the ISS could be maximized, the task group looked at two possibilities: options based on the restoration of certain critical capabilities to the ISS, and options based on the current Core Complete configuration. Described below are the steps that would have the greatest impact on the overall research potential of the ISS. Suggestions for additional steps that would maximize research in specific disciplines are made in the discipline chapters of the report.
Currently a tension seems to exist between using ISS research resources (such as crew time) to enable the human exploration of space, and using those resources to perform research that has intrinsic scientific importance. These two goals are not mutually exclusive, but without cross-disciplinary prioritization both within and across the research supporting the two goals, intelligent use of the scarce and costly resources of the ISS is impossible. As this report is being written, no cross-disciplinary prioritization plan exists.2 This lack of cross-disciplinary prioritization exacerbates the uncertainty that is undermining the confidence of the scientific community and its readiness to support the program.
Recommendation: NASA should create a cross-disciplinary research prioritization plan with accompanying rationale, based on overall program goals for the ISS, that permits ranking and can be used to effectively manage the scientific program.
In the life sciences, the human physiology research and operational medicine programs both involve activities that influence or perturb the same physiologic parameters in astronauts. Currently, these activities are not coordinated systematically, which can result in inadvertent corruption of scientific data as well as inefficient expenditure of resources.
Recommendation: NASA should establish systematic coordination between human physiology research and operational medicine on the ISS so that crew care is not compromised and coordinated acquisition of scientific data is facilitated.
As already noted, the time available for science activities on the ISS is wholly inadequate and is the single biggest factor that is limiting achieving science objectives. Of the approximately 20 hours of crew time per week currently identified by NASA for science-related activities, the United States will be allotted only 7.5 hours. This is not sufficient to take advantage of even the reduced scientific capabilities of the Core Complete ISS. According to NASA, the factor currently limiting the crew size to three is the inability, in the event of an on-board emergency, to deorbit more than three crew members due to the limited capacity of the Soyuz and the indefinite postponement of the planned Crew Return Vehicle.
Recommendation: In view of the effect of crew return options on crew size, NASA should reevaluate the assumption that the crew return requirement in case of an emergency is the best approach to maintain crew safety and achieve mission success. For example, there may be other options such as safe haven concepts that would maintain crew safety and permit a crew of seven. If it is determined that there is a requirement to return the ISS crew to Earth immediately, NASA should develop a plan whereby the original complement of seven crew members can be accommodated by a return vehicle so that the scientific objectives of the ISS can be met.
Recommendation: NASA should evaluate the adequacy of the time allotted to perform the science that is scheduled for the ISS, taking into account interdisciplinary priorities and the equipment and facilities that are available. Caution should be used when allocating the hours available for science investigations, since small allocations to individual crew members often involve overhead that may render the time operationally ineffective for research even though the total time spent meets the experiment requirements documentation. In addition, NASA should carefully consider what steps could be taken to reduce demands on on-orbit crew time. For example, any reduction in the time needed for ISS maintenance would have a large positive impact, in percentage terms, on the small amount of crew time now available for science.
The transition of the ISS from Rev. F to Core Complete has severely limited the facilities available to accomplish U.S.-based scientific research. Increased collaboration with international partners to share facilities and crew time could enable research that the U.S. science community cannot accomplish alone.
Recommendation: To maximize ISS facility usage NASA should promote further collaborative interactions between the ISS science programs of the United States and those of its international partners in all disciplines.
Experiment Equipment and Facilities
The elimination or postponement of ISS experiment racks, modules, and equipment has greatly reduced the potential scientific yield of the ISS. Once a science prioritization on a cross-disciplinary basis is accomplished and the number of crew members available for scientific activities is finalized, the decisions about which experimental modules and experimental equipment are needed can be addressed intelligently. A rational plan that is consistent with stated scientific priorities is critical to assuring the scientific community that the ISS has a scientific future.
Recommendation: NASA should develop a plan providing for ISS experiment racks, modules, and equipment that is consistent with the scientific priorities of NASA and the ISS and is achievable within fiscal and schedule constraints.
The development cost to the United States of the ISS as currently planned is approximately $26 billion. The additional cost to increase the crew number to seven has been estimated at approximately $5 billion (IMCE, 2001).3 This 20 percent increase in development cost would yield a 900 percent increase in the crew time available for research (4.5 versus 0.5 crew available for scientific activities). If the primary objective of the ISS is indeed to be a world-class laboratory in space, then the cost-benefit of taking this course of action is obvious. Not to do so would be akin to building a million-dollar home but stopping short of running electrical and water services to it. Without plans and decisions based on cross-disciplinary priorities that are clearly articulated and supported by corresponding allocations of resources, the ISS can never achieve the status of a world-class research laboratory.