Review of NASA Plans for the International Space Station (2006)

NASA gave the panel background materials and briefings that explained at varying levels of detail how the International Space Station (ISS) would or should be utilized in support of the exploration initiative. A number of common terms were used in these materials that had specialized meanings to NASA within the context of these programs. For the sake of clarity, the panel defines in Box 2.1 its understanding and use of these terms: enabling research, operational experience, operations demonstrations, technology demonstrations, utilization, and utilization planning.

The ISS utilization roadmapping effort sought to integrate several separate analyses that bear on ISS utilization in the context of the current exploration systems architecture. These studies include, in roughly chronological order:

• Research Maximization and Prioritization Task Force study, an external review of the established ISS research portfolio, conducted in 2002.

• Zero-Base Review of the Human System Research and Technology Office, an internal study that preceded definition of the exploration systems architecture. The findings of this review and earlier realignments of the role of the former Office of Biological and Physical Research resulted in reductions in non-exploration-related elements of the NASA research portfolio, including fluid physics, materials science, combustion, atomic physics, and animal/cell biotechnology.

• Exploration Systems Architecture Study (ESAS) Technology Assessment, an internal study utilizing a formalized decision analysis methodology, whose goal was to identify and enable key technologies required for the exploration systems architecture.

• Exploration Systems Mission Directorate (ESMD) Analysis of ISS Utilization Requirements, an internal analysis that used a decision support methodology with quality function deployment and analytical hierarchy process, and whose purpose was to establish the priorities for ESMD utilization of the ISS.

• Station/Shuttle Configuration Options Team analysis, a recent internal study that recommends deletion of the Russian science power module and the Japanese-built centrifuge accommodation module.

Although these reports had not been integrated to produce a complete roadmap at the time of this panel’s review, it was clear that a great deal had been accomplished in a fairly short time. Unfortunately, time pressure led to a more superficial treatment of some issues than would normally be desirable, and several areas of concern were noted by the panel.

First, the results presented from the various decision support tools did not seem to contain any weightings associated with relative or absolute risk. There are numerous relevant risks, for everything from human health to small team dynamics to system operations to organizational risks.¹ The panel is concerned that these tools will therefore provide unreliable guidance to decision makers as they trade off risks and resources.

Second, the requirements for use of the ISS to support the exploration missions (out to and including a Mars mission) do not appear to be fully identified, even though the ISS might prove to be a necessary facility to address these requirements (irrespective of its current set of manifests and payloads). This is particularly troubling because if the ISS is shown to be the only facility where specific risk-

reducing R&D or operations demonstrations can be conducted, these tasks must be migrated to a new ISS utilization plan as soon as possible if there is to be any chance of carrying them out.

Third, none of the planning, prioritization, or utilization studies that the panel was shown appeared to have fully and thoroughly aligned ISS utilization with the needs of the exploration missions as expressed in the ESAS Technology Assessment. While this issue is similar to the one raised above, the point here is that the panel did not see evidence that even current ISS payloads have been aligned thoroughly with exploration mission needs.

Finally, the panel believes it is highly likely that a limited number of new research experiments and operations demonstrations will be identified as necessary to enable the full suite of exploration missions if NASA’s process for realigning ISS utilization rigorously reassesses needs without regard for current ISS utilization planning. In the information presented to it, the panel saw no place within the planning process for inserting new research experiments or operations demonstrations.

The ESAS Technology Assessment presented to the panel showed that the decisions leading to the selected exploration architecture^a had relied heavily on a computerized decision support tool (for use in prioritizing technologies and ISS experiments, for instance). This tool was able to produce detailed tables and data summaries that created the impression they were supported by validated data.

Unfortunately, the panel found that many of the weighting factors (such as for risk) had been based, at best, on expert opinion and not on hard data. While this may have been a consequence of time pressures, it means that the prioritization decisions were not based on any standardized evaluation of risk to the mission or crew as compared to a defined acceptable level of risk. Absent a means to compare the relative risks in this way, the data from any decision support tool will incompletely inform NASA’s decision-making process and may well provide unreliable information to those who must make the final decisions that trade off risks and resources.

Finding: A widespread lack of explicit risk-based go/no-go criteria is notable in the evaluations presented to the panel. This weakness is manifest in many areas but is particularly critical when it comes to prioritizing what work needs to be done with respect to time and other limited resources such as cost, crew time, and so on.

Recommendation: As has been discussed elsewhere,² the characterization of risk should be clearly communicated, along with concrete go/no-go criteria for missions, so as to achieve a rational and supportable allocation of ISS resources.

In all the presentations it was clear that the overarching goal was support of exploration missions: a crew exploration vehicle to low Earth orbit (LEO)/ISS, a lunar sortie, a lunar outpost, and a Mars mission. However, it was not clear which criteria and procedures were used to set priorities for utilization of the ISS in support of these quite different missions, nor do the requirements for use of the ISS to support the exploration missions (out to and including a Mars mission) appear to be fully identified, even though the ISS, irrespective of its current set of manifests and payloads, might turn out to be a necessary facility to address those requirements.

Efforts to align the current ISS payload portfolio with the ESMD ISS utilization requirements can best be described as nascent. The ESMD utilization team specifically recommended that its results should not be used to prioritize individual payloads or experiments, saying “more work would be required to refine data at the project level.” In response to follow-up questions, briefers stated explicitly that no activity was complete that attempted to prioritize individual experiments in the current payload portfolio in relation to ESMD requirements for research and technology (R&T). The ESMD utilization team used assessments by subgroups in each R&T area reflecting the subgroups’ perceptions of the value of each ISS facility toward accomplishing their R&T requirements. In these assessments, lunar missions were emphasized. The current portfolio of funded payloads (many of which had been designed, proposed, and reviewed in the mid- to late-1990s) was then used to populate the facilities deemed most valuable, without consideration as to how specific data or results obtained by that experiment would meet exploration goals.

In addition, in the ESMD Analysis of ISS Utilization Requirements a weighting factor for relevance was employed that assigned the lunar outpost a priority of 0.44 as compared to 0.27 for the Mars mission, 0.23 for a lunar sortie, and 0.05 for a crew exploration vehicle to LEO/ISS (Figure 2.1). These relative weights reflected internal stakeholder opinions about what needed to be improved to meet the exploration objectives, but the criteria on which the opinions were based were not clear to the panel.

In particular, this prioritization method did not seem to take into account the possibility that weight factors are cross-correlated. For example, assigning a high priority to one mission could have a significant effect on the ability to complete another, later mission. Other issues include the possibility that earlier missions might use up the resources needed by later missions, or that long lead-time items that are part of the critical path for later missions will be ignored until it is too late to make scheduled milestones. NASA’s decision analysis results using uncorrelated weighting factors are shown in Figure 2.2.

Finding: The criteria and processes used to examine priorities for utilization of the ISS are poorly defined with respect to allocation of ISS-based resources for different exploration missions. In particular, the materials presented to the panel did not seem to take into account the effects that high priorities assigned to one mission would have on factors such as the ability to complete another, perhaps later mission, through depletion of necessary resources or limitation of necessary lead times.

None of the variety of plans provided to the panel appear to have fully and thoroughly aligned ISS utilization with the needs of the exploration missions as expressed in the ESAS Technology Assessment. The panel did not see evidence that even current ISS payloads have been aligned completely with the needs of exploration missions. (This explained NASA’s failure to present any overview of an integrated plan describing how the various requirements for a successful exploration program would be achieved, especially with respect to an optimal utilization of the ISS.) This is cause for concern due to the limited time left for utilization of the ISS, the complex relationship between the components of any single exploration mission and the components of other missions in the exploration initiative, and the possibility that, for a Mars mission, the ISS may be the only facility capable of conducting some crucial studies.

Finding: No evidence of an integrated resource utilization plan for use of the ISS in support of the exploration missions was presented to the panel, and indeed it appears that no such integrated plan exists.

Recommendation: NASA should develop an agency-wide, integrated utilization plan for all ISS activities as soon as possible. Such a planning effort should explicitly encompass the full development of the Exploration Systems Architecture Study technology requirements, migration of current ISS payloads to meet those requirements, identification of remaining gaps unfilled by current ISS payloads, and the R&D and technology or operations payloads needed to fill those gaps. An iterative process that includes Exploration Systems Mission Directorate stakeholders and the external scientific and technical community should be employed to ensure that the as-flown experiments closely match the integrated ISS utilization plan.

There is a complete absence of consideration for enabling research that may be necessary to solve exploration problems or to reduce crew and mission risk. For example, the panel expected to see such R&D gaps identified in the ESAS Technology Assessment, but they were not. The ISS offers a unique opportunity to conduct such research and may well represent the only timely opportunity before a Mars mission.

Finding: Enabling research is not a clearly stated objective for use of the ISS in support of exploration missions. Even in an era of extremely limited resources, for R&D that is necessary to solve exploration problems and reduce crew and missions risks, the ISS may well represent the only timely opportunity to conduct such R&D prior to a Mars mission.

Recommendation: NASA should state that the objective for ISS utilization in support of exploration missions is to conduct enabling research for (1) technologies for exploration, (2) ways to maintain crew health and performance for missions beyond low Earth orbit, and (3) development of an operational capability for long-distance flights beyond low Earth orbit.

Recommendation: Based on the involvement of a broad base of experts and a rigorous and transparent prioritization process, NASA should develop and maintain a set of research experiments to be conducted aboard the ISS that would enable the full suite of exploration missions. These experiments should be fully integrated into the ISS utilization process.

Although one of the objectives for ISS utilization for exploration missions is to “gain operational experience that can be applied to exploration,” it appears that operations demonstrations have not been included in the current planning for ISS. The ISS environment offers a unique and timely opportunity to demonstrate operations protocols and procedures such as autonomous crew operations and protocols for communications between the crew and the ground.

Finding: A rigorous definition of operations demonstrations requirements for exploration missions has not been done, and such requirements are not a part of the exploration utilization plan.

Recommendation: Using a rigorous process based on formal prioritization and involvement of the operations community, NASA should develop and maintain a set of operations demonstrations that need to be conducted on the ISS to validate operational protocols and procedures for long-duration and long-distance missions such as the ones to Mars. These demonstrations should be integrated into utilization of the ISS to support exploration.

The stated goal of the ESMD Analysis of ISS Utilization Requirements was to establish priorities for ESMD use of the ISS for research purposes. Life support technologies and environmental controls and monitoring were accorded the highest priority with respect to both “need for ISS” and “contribution to requirements.” The panel agrees with this assessment.

The recent IOM and NRC review of NASA’s bioastronautics roadmap emphasized as follows:³

It is troubling, therefore, that the information presented to the panel suggests use only of advanced environmental control and life support systems currently under development. What appears to be missing is an analysis of risk and a consequent risk reduction program to drive the next generation of effective and efficient life support system technologies that will be needed for long-duration, long-distance missions to Mars. For these lengthy, low-gravity, no-abort transit missions, life support equipment that functions and can be maintained in microgravity for prolonged periods will be needed in some form. It is highly unlikely that the ISS advanced environmental control and life support systems currently under development will meet these needs. However, any new concepts for such equipment will have to be tested in a relevant environment.

Finding: Next-generation life support system and environmental control technology demonstration requirements for long-duration, long-distance exploration missions have not been defined and are not included in ISS exploration utilization planning.

Recommendation: Using a well-defined risk-based prioritization scheme and including broad-based expertise, NASA should develop and maintain a set of requirements for ISS technology demonstrations for next-generation life support and environmental control systems for long-duration, long-distance missions.

The failure to thoroughly scrutinize the results generated by evaluation tools can be attributed to the short time NASA had to formulate ISS plans and to the state of flux in many areas at NASA. However, the panel strongly believes that some form of ongoing external review would improve NASA’s ability to produce an actionable plan for ISS utilization that addresses and solves gaps in knowledge and understanding necessary to successfully complete exploration missions.

Recommendation: Scheduled periodic reviews of the ISS utilization plan with the participation of a broad group of stakeholders (internal and external, scientific and operations) are needed to ensure that the plan remains appropriate and it continues to promote an integrated approach to attaining the ultimate program goals.

1. Institute of Medicine (IOM) and National Research Council (NRC). 2006. A Risk Reduction Strategy for Human Exploration of Space: A Review of NASA’s Bioastronautics Roadmap. The National Academies Press, Washington, D.C.

2. IOM and NRC. 2006. A Risk Reduction Strategy for Human Exploration of Space.

3. IOM and NRC. 2006. A Risk Reduction Strategy for Human Exploration of Space, pp. 82-83.