Factors Affecting the Utilization of the International Space Station for Research in the Biological and Physical Sciences (2003)

This report represents phase II of a study requested by Congress and conducted by the Task Group on Research on the International Space Station to examine factors affecting the utilization of the International Space Station (ISS) for research. The phase I report, released in September of 2001, looked at the readiness of the scientific community to utilize the ISS¹ and the benefits and costs of flying additional shuttle missions dedicated to science during the station build-up² (NRC, 2001). During the course of that study, the National Aeronautics and Space Administration (NASA) announced that it would make major changes in the final ISS configuration in order to address construction cost overruns. These design changes (discussed below) would reduce considerably the research capabilities of the ISS and therefore had to be taken into account when the task group made its phase I recommendations. While the task group concluded in that report that the research community was in fact ready to utilize the ISS, it also pointed out that the uncertainty resulting from years of schedule delays, funding fluctuations, and lack of flight opportunities seriously threatened the continued viability of the ISS research community in many disciplines. The task group also noted that the planned reductions in ISS capabilities would exacerbate this problem considerably.

An implication of the conclusions of the phase I report is that, given the research capabilities of the redesigned ISS, the planned science would be best supported by flying additional annual shuttle missions dedicated to science even if the cost of such missions slowed ISS development. However, implementation of the task group’s recommendation now appears extremely unlikely—in fact, since the release of the phase I study, NASA has effectively canceled one³ of its two remaining shuttle missions dedicated to science and has reduced the total number of shuttle flights per year.

For phase II of the overall study, the original charge⁴ to the task group was as follows:

While these tasks remained unchanged as the task group began its work, concerns about the impact of the ISS redesign prompted Congress⁵ to ask that the task group attempt to address additional issues during its phase II study. The task group was unable to accommodate that request fully, given the time available for the study, but it did agree that the following requested analysis fell within the scope of its current task: “compare and evaluate the research programs of the ISS which can be accomplished with a crew of three and a crew of six [or seven].”

Though the task group had addressed in its phase I report the overall impact on research of the changes to the ISS design, in order to address the above issues it needed to perform a more detailed analysis of that impact. In the chapters that follow the report looks at the impact of the redesign on a discipline-by-discipline basis, compares within each discipline the types and levels of research that could be supported by the previous and current designs for the ISS, and attempts to provide specific suggestions

for steps that NASA and the research community could take to maximize the research potential of the ISS.

When a major redesign of the ISS was announced in the spring of 2001, the new ISS configuration was initially referred to as the Rev. G design (the previous design had been Rev. F). Many aspects of the Rev. G design,⁶ which is now called “Core Complete,” are still highly fluid, and NASA has left open the possibility that it might eventually be able to restore some of the deleted elements of the Rev. F design in the eventuality that cost and schedule problems are resolved and money becomes available. Despite this possibility of restoration, in the past year NASA has moved forward rapidly with plans to adopt the Core Complete design, including extensive changes in shuttle schedules and facility funding. Tables 1.1 and 1.2 illustrate the task group’s understanding of many of the current differences between the Rev. F and Core Complete designs for ISS.

The most critical difference between the Rev. F design and the Core Complete design resulted from the deletion of the crew return vehicle, which reduced the number of crew that could live aboard the completed ISS, from six or seven to three. Since NASA has estimated that 2.5 crew members will be needed to maintain and operate the ISS, the number of crew available to perform scientific research drops from 3.5 or 4.5, to 0.5, a decrease of at least 85 percent. Of this remaining research time, the U.S. share is currently 50 percent⁷ and will drop to 38 percent once the laboratories of the international partners are brought into orbit.⁸ Based on NASA’s planned work week of 40 hours per crew member, a total of 20 hours would be devoted to research each week, with about 7.5 hours of this going to U.S. research. NASA data indicate that early ISS crews have chosen to work considerably longer than 40 hours per week, and some of that time has been devoted to performing additional experiment runs and procedures. However, this additional effort is unplanned and so the amount of supplementary science that can be obtained in this way is likely to be modest. NASA guidelines require that payload planning must be based on the assumption of a 40 hour week as this most accurately describes what can be accomplished on orbit. This assumption is further supported by the fact that NASA anticipates that crew time required for ISS maintenance and repair will rise on future missions as more elements are added to the ISS and the original elements accumulate hours of operation.

Since the release of the phase I report, NASA has reduced the number of planned shuttle flights for ISS to four flights per year. This may be an even more serious constraint on ISS science than the reduction in crew size. The task group has learned that NASA’s current analysis predicts that by the time the centrifuge accommodations module is launched,⁹ the entire upmass capacity of the four flights per year will be needed for the ISS logistics and maintenance hardware, leaving only limited capability for research outfitting and resupply. NASA is currently studying this issue, and few details are available at this time.

Also affecting the science capabilities of the completed ISS is the elimination of a number of research facilities from Rev. F, as shown in Table 1.2. Note that the loss of racks shown here does not capture the additional impact of deleted experiment modules, which are the functional experiment units that go into these racks. Most of these facilities and modules supported research in specific scientific fields and, as noted in the phase I report and discussed in detail in the chapters that follow, the impact of their elimination will vary by discipline. While the centrifuge, a key facility for life sciences research, is

currently still included in the Core Complete design, it has experienced numerous development delays and is not expected to be launched prior to 2007 at the earliest.

Ironically, it is the capabilities that were most unique to the ISS that are most threatened by the changes in the configuration. The complex, dedicated scientific facilities and the availability of astronaut scientists with time to perform experiments, analyze results, and then design successive series of experiments based on those results were intended to enable sophisticated research studies to be carried out in space much as they would be on the ground. This opportunity to perform iterative experiments and to replicate results—particularly unexpected results—was a key advantage of the ISS as compared to Spacelab. Also important were the advanced scientific facilities that required too much volume, power, or other resources to be feasible on a Spacelab mission. Under current planning scenarios, the ISS will now provide less crew time dedicated to science annually than did Spacelab, and many facilities that were to perform world-class science are threatened with cancellation or downgrading to smaller, less capable equipment. While the ability to run experiments that require more than 10 to 14 days for completion is an advantage that Core Complete still retains over Spacelab, this capability may not be useful without adequate crew time and other resources.

In comparing the science capabilities of Rev. F and Core Complete, the task group considered the possibility that facilities provided by international partners—such as those planned for the European Space Agency’s (ESA’s) Columbus module—could replace capabilities that would have been provided by canceled U.S. facilities. Current ISS partner agreements allocate an overall percentage of time on these facilities to U.S. investigators. It should be noted, however, that the time available to the task group did not allow for a thorough exploration of this option. Furthermore, since the choice of international partner facilities was made with the intent of complementing rather than duplicating U.S. capabilities, the task group did not expect to find numerous instances where partner facilities could actually replace U.S. capabilities. In addition, because ISS design changes have created uncertainty about the eventual level of

participation by international partners, the task group considered it problematic to assume that these facilities would be available on the ISS and thus to U.S. investigators.

The manner in which scientific disciplines in the biological and physical sciences have been categorized and labeled in NASA programs has varied considerably during the past decade. To consider separately every discipline or subdiscipline that is, or has been, defined in NASA programs was not practical in this brief study. However the task group has analyzed a representative sampling of the scientific disciplines that have been supported by the Office of Biological and Physical Research (OBPR), and most of the disciplines that were expected to be heavily dependent on the ISS as a vehicle for future space research are discussed specifically in the chapters that follow.

For the benefit of general readers, the research areas covered in this report are organized into the broad categories of physical sciences, fundamental biology, and bioastronautics (human physiology and performance). It should be noted that these categories do not necessarily align with current OBPR organizational charts, some of which have been considerably altered in recent years. For each discipline examined within those categories, a separate and independent assessment was made of:

• The impact of ISS changes on the discipline,

• The factors limiting the utilization of the ISS by that discipline community, and

• Possible steps for maximizing the research potential of the ISS for that discipline community.

This discipline-by-discipline examination was intended to ensure that the task group understood both the differences and similarities of ISS utilization by the discipline communities in more detail than would have been possible with a more global analysis. Each discipline section of the report, therefore, has a similar structure, and issues common to multiple disciplines appear repeatedly in different sections of the report. The findings and recommendations that are common to many disciplines are summarized in Chapter 5. For issues and recommendations specific to a limited number of disciplines the reader is referred back to the individual chapters.