Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report of the Committee on Review of NASA’s Bioastronautics Critical Path Roadmap

SUMMARY

Extending the spatial and temporal boundaries of human space flight are important goals for the National Aeronautics and Space Administration (NASA), yet human space flight remains an endeavor with substantial risks. NASA’s Bioastronautics Critical Path Roadmap (BCPR) defines risk as “the conditional probability of an adverse event occurring, or a system performance-related inefficiency.” Potential hazards include exposure of the crew to space radiation, degraded crew performance related to human behavioral and other health changes, failure of life support systems, and the adverse effects of space flight on human biological systems including the musculoskeletal, cardiovascular, neurovestibular, endocrine, neuropsychiatric, and immune systems. Human factors are critically important in risk assessment and countermeasure development, including engineering design for human space flight. The BCPR is designed to provide summary assessments of the importance of each risk, and the current state of science and technology with respect to minimizing them.

In 2003, NASA asked the Institute of Medicine (IOM), in collaboration with the Division on Engineering and Physical Sciences of the National Academies, to conduct a review of the BCPR (see Appendix B for the version of the BCPR that the committee reviewed). Specifically, NASA asked the committee to (1) conduct a comprehensive assessment and report of the strengths and weaknesses of the content and processes of the BCPR as applied to the missions described in the President’s exploration initiative



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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report of the Committee on Review of NASA’s Bioastronautics Critical Path Roadmap SUMMARY Extending the spatial and temporal boundaries of human space flight are important goals for the National Aeronautics and Space Administration (NASA), yet human space flight remains an endeavor with substantial risks. NASA’s Bioastronautics Critical Path Roadmap (BCPR) defines risk as “the conditional probability of an adverse event occurring, or a system performance-related inefficiency.” Potential hazards include exposure of the crew to space radiation, degraded crew performance related to human behavioral and other health changes, failure of life support systems, and the adverse effects of space flight on human biological systems including the musculoskeletal, cardiovascular, neurovestibular, endocrine, neuropsychiatric, and immune systems. Human factors are critically important in risk assessment and countermeasure development, including engineering design for human space flight. The BCPR is designed to provide summary assessments of the importance of each risk, and the current state of science and technology with respect to minimizing them. In 2003, NASA asked the Institute of Medicine (IOM), in collaboration with the Division on Engineering and Physical Sciences of the National Academies, to conduct a review of the BCPR (see Appendix B for the version of the BCPR that the committee reviewed). Specifically, NASA asked the committee to (1) conduct a comprehensive assessment and report of the strengths and weaknesses of the content and processes of the BCPR as applied to the missions described in the President’s exploration initiative

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report and (2) identify the unique challenges for accomplishing its goals and objectives. Specific questions for the committee to answer included but were not limited to the following: How can the BCPR better capture and describe the critical risks and key research and technology issues for risk reduction and management so as to provide a framework for informed decisions regarding resource allocation? Does the BCPR use an appropriate method of risk assessment and expression of risk assessment? Does it adequately communicate the methods underlying risk assessment and the resulting activities for different mission scenarios? How well does the BCPR address different types of risk (e.g., health, engineering) and their impact? Are the categories of critical research issues and the metrics used to analyze them appropriate (risk assessment and characterization, mechanistic/process research, countermeasure development, and medical diagnosis and treatment)? Are efficiency and technology issues properly and adequately addressed? This is the interim report of the IOM committee’s review of NASA’s BCPR. The purpose of this report is to provide NASA with preliminary conclusions regarding the strengths and weakness of the BCPR. Over the next several months, the committee will continue to gather data and information and meet with NASA personnel, including senior leadership, other NASA decision makers, and those in operational areas related to the human space flight program. The committee’s final report, due in August 2005, will elaborate on these preliminary conclusions and provide NASA with recommendations about how to address the issues that are identified by the committee. The BCPR was developed collaboratively by NASA’s Office of Biological and Physical Research, the Office of Space Flight, and the Office of the Chief Health and Medical Officer. NASA describes the BCPR as a framework for identifying and assessing the risks to crews that are exposed to the hazardous environments of space.1 The roadmap identifies risks 1   Bioastronautics spans research, technological, medical/operational, and policy issues related to understanding and managing the human consequences of space flight.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report and associated research questions related to human space flight. The goal of the BCPR is to obtain empirical evidence and systematic data for risk reduction and management. The roadmap represents a comprehensive and thoughtful approach to meeting the challenges of the President’s space initiative, specifically, a 1-year mission to the International Space Station, a month-long stay on the lunar surface, and a 30-month round-trip journey to Mars. Currently, the BCPR identifies 35 human health–related risks and 15 risks related to systems performance and efficiency clustered in five cross-cutting areas (human health and countermeasures, radiation health, behavioral health and performance, autonomous medical care, and advanced human life support technologies). Efforts to understand and manage the risks associated with human space flight have been ongoing at NASA for many years, and specific activities related to the development of a roadmap began in the early 1990s. The process of risk identification that resulted in the BCPR commenced in 1997, in brainstorming sessions involving NASA and non-NASA experts who rated risks within their own discipline areas. With guidance from NAS and other advisory reports (see Appendix C), 150 risks were identified. More recently, and after several iterations, the list was culled to the 50 risks that are the focus of the current BCPR. The final risks and related critical questions were identified by the discipline teams using the advisory committee reports as well as other recent research findings. The Bioastronautics Science Management Team, which includes NASA scientists, managers, and flight surgeons, and the National Space Biomedical Research Institute (NSBRI) Director, reviewed and discussed the risks and provided oversight for the project. The current set of 50 risks is the product of those deliberations. For communication and decision-making regarding these risks, the BCPR uses a visual metaphor called a stoplight chart in which red/yellow/green categories replace the NASA standard 5 × 5 model of risk assessment (see Box 1). In the spring of 2004, NASA held several consensus workshops that included the research community and NASA operations communities (flight surgeons, astronauts, and the medical office) to address the sample size needed for research related to the risks identified, the use of animal models, and the ranking of the 35 biomedical risks in the BCPR from the point of view of the astronauts and flight surgeons. Of note, the Workshop on Requirements for Human Subjects for Exploration Research, held on June 9, 2004, concluded that although 10 research subjects per flight experiment (astronauts may participate in more than 1 research project per

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report BOX 1 NASA 5 × 5 Matrix Model SOURCE: Connley, Warren. Code 300 All Hands: NASA-wide risk reporting. NASA. November 7, 2002. flight) would serve as a feasible minimum sample, it would still place limits on the statistical power of the data from in-flight research. Since its creation in January 2004, the Committee on Review of NASA’s Bioastronautics Critical Path Roadmap has held three meetings (see Appendix A for details). Each meeting included a data-gathering session where testimony from NASA officials and space science experts was heard. At each meeting, the committee also held closed sessions where it deliberated and developed conclusions. This interim report presents the committee’s preliminary assessment of the strengths and weaknesses of the BCPR in terms of risk identification, inclusion of operational priorities, sample size considerations, understanding about the interactions among risks, and risk-assessment and communication methods. The report outlines areas in the BCPR that merit more attention from NASA and provides the committee’s preliminary conclusions concerning the need for users of the BCPR to be able to assess the quality of the science that forms the basis for decision making reflected in the document;

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report the potential impact of the President’s space initiative on the organizational-level risk that NASA faces; the importance of time as a dimension of risk analysis, especially in the context of long-term missions; the problems associated with very small sample size, which characterizes in-flight, health-related studies; the need for incorporating results of ongoing research into the calibration of risk in the BCPR to help ensure that the roadmap is a dynamic document that is used throughout the agency; the importance of human factors in space engineering design; and the relevance of data from analog environments for understanding the risk of human space flight. INTRODUCTION As the boundaries of distance and flight duration are extended, demands on the crew change and increase. The nature and severity of the risks also change as the duration of space flight increases, and time becomes an important element in assessing the risks associated with human space flight. On a 30-month Mars mission, for example, abort modes and opportunities for early return do not exist, demanding greater commitment from NASA and the crew. The need for the crew to function autonomously becomes imperative. Social tensions, lack of privacy, noise, disrupted sleep patterns, and lack of leisure time can produce mounting stress on the crew. Expectations for autonomous performance of the crew include diverse skills such as the delivery of medical care, including self-care; provision of food and water; maintenance of vehicle systems; and performance of independent research. In the President’s space initiative, NASA has a proposed schedule that demands considerable resources, notably time and funding. Crew safety and mission success require an understanding of the effects of long-duration space flight, which entails, for example, prolonged isolation, exposure to microgravity, and the potential of technology failure. As flight duration increases, the cumulative impact of risks and their sequencing may change. Unfortunately, the number of astronaut-days remaining on the International Space Station (ISS) is very limited relative to the time needed for carrying out critical research and testing countermeasure readiness.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report The President’s Initiative On January 14, 2004, President Bush announced his vision for space exploration. The President’s plan for continued human and robotic space exploration is summarized in Box 2. The BCPR refers to three scenarios in the plan as “design reference missions” and describes them as follows: (1) a 1-year mission to the ISS; (2) a 1-month stay on the lunar surface; and (3) a 30-month journey to Mars and back. Overview of the BCPR NASA describes the BCPR as a framework for identifying and assessing the risks to crews that are exposed to the hazardous environments of BOX 2 President Bush’s Vision for U.S. Space Exploration The President’s plan for steady human and robotic space exploration is based on the following goals: First, America will complete its work on the International Space Station by 2010, fulfilling our commitment to our 15 partner countries. The United States will launch a re-focused research effort on board the International Space Station to better understand and overcome the effects of human space flight on astronaut health, increasing the safety of future space missions. To accomplish this goal, NASA will return the Space Shuttle to flight consistent with safety concerns and the recommendations of the Columbia Accident Investigation Board. The Shuttle’s chief purpose over the next several years will be to help finish assembly of the Station, and the Shuttle will be retired by the end of this decade after nearly 30 years of service. Second, the United States will begin developing a new manned exploration vehicle to explore beyond our orbit to other worlds—the first of its kind since the Apollo Command Module. The new spacecraft, the Crew Exploration Vehicle, will be developed and tested by 2008 and will conduct its first manned mission no later than 2014. The Crew Exploration Vehicle will also be capable of transporting astronauts and scientists to the International Space Station after the Shuttle is retired.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report space. The roadmap identifies risks and associated research questions related to human space flight. The goal of the BCPR is to obtain empirical evidence and systematic data for risk reduction and management. Some risks (see Table 1) are specific to traditional space life science disciplines, whereas others are of a cross-cutting nature and require an integrated approach, for example, human response to stress, which may include psychological, neurological, and immunological change. Examples of discipline-specific risks include the acceleration of age-related osteoporosis, decompression sickness, and cardiac dysrhythmias. All of the risks in the BCPR were initially identified and assessed through the deliberation of expert panels that included extramural scientists, NASA intramural scientists, and operational and management staff. Third, America will return to the Moon as early as 2015 and no later than 2020 and use it as a stepping stone for more ambitious missions. A series of robotic missions to the Moon, similar to the Spirit Rover that is sending remarkable images back to Earth from Mars, will explore the lunar surface beginning no later than 2008 to research and prepare for future human exploration. Using the Crew Exploration Vehicle, humans will conduct extended lunar missions as early as 2015, with the goal of living and working there for increasingly extended periods. The extended human presence on the Moon will enable astronauts to develop new technologies and harness the Moon’s abundant resources to allow manned exploration of more challenging environments. An extended human presence on the Moon could reduce the costs of further exploration, since lunar-based spacecraft could escape the Moon’s lower gravity using less energy at less cost than Earth-based vehicles. The experience and knowledge gained on the Moon will serve as a foundation for human missions beyond the Moon, beginning with Mars. NASA will increase the use of robotic exploration to maximize our understanding of the solar system and pave the way for more ambitious manned missions. Probes, landers, and similar unmanned vehicles will serve as trailblazers and send vast amounts of knowledge back to scientists on Earth. SOURCE: http://www.whitehouse.gov/infocus/space/vision.html.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report TABLE 1 BCPR Discipline Teams and Cross-Cutting Areas (Table 4-2 of the BCPR) Discipline Teams Cross-Cutting Areas Bone Loss Muscle Alterations & Atrophy Neurovestibular Adaptation Cardiovascular Alterations Immunology, Infection & Hematology Environmental Effects Human Health and Countermeasures (HH&C): Focuses on understanding, characterizing, and counteracting the whole body’s adaptation to microgravity, enabling healthy astronauts to accomplish mission objectives and return to normal life following a mission. Radiation Health Radiation Health: Defines the research strategy and sets radiation shielding and monitoring requirements, thus increasing allowable crew time in space and reducing uncertainty for cancer and other radiation risks. Psychosocial Adaptation Sleep & Circadian Rhythm Problems Neurobehavioral Problems Cognitive Abilities Behavioral Health and Performance (BH&P): Focuses on maintaining the psychosocial and psycho-physiological functions of the crew throughout space flight missions and providing an optimal set of countermeasures. Clinical Capabilities Autonomous Medical Care (AMC): The capability to provide medical care during a mission with little or no real-time support from Earth. Crew medical officers or other crew members provide routine or emergency medical care using available resources. The local resources in an autonomous system augment and support the caregiver. Additionally, part of creating an autonomous medical care system includes preventing or reducing the likelihood of conditions before a mission starts, thus reducing the capabilities and consumables needed in the medical system. Advanced Food Technology (AFT) Advanced Life Support (ALS) Advanced Environmental Monitoring & Control (AEMC) Advanced Human Support Technologies (AHST): Focuses on developing efficient, reliable, and autonomous technologies and systems to support human habitation in

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report Discipline Teams Cross-Cutting Areas Advanced Extravehicular Activity (AEVA) Space Human Factors Engineering (SHFE) Advanced Integration Matrix (AIM) spacecraft and planetary dwellings. These technologies include food and life support systems, environmental monitoring and control systems, extravehicular activity technologies, and human factors solutions through integrated testing in appropriate facilities. SOURCE: NASA, 2004. Risk assessment criteria included the determination of the likelihood of occurrence and the severity of consequences of each risk in terms of crew health and safety, and performance of mission objectives. Relative risk priorities were derived from that assessment. Each risk has a set of critical questions whose answers are intended to lead to (1) risk assessment and quantification, (2) the development of countermeasures to prevent or mitigate the deleterious effects of space flight, (3) an improved basic understanding of underlying processes, and (4) medical diagnostic and treatment capabilities. This risk-based approach was devised to enable the development of a more rigorous decision-making process for the allocation and implementation of resources, risk prioritization, access to facilities, operational requirement implementation, and crew time, as well as for the development of cost-effective countermeasures, and the design and implementation of effective advanced life support technology. The determination of risk always involves an element of uncertainty. To fully communicate the likelihood of occurrence of an event, it is necessary to communicate the extent of uncertainty in the assessment. For risk communication, the uncertainty associated with a risk may be represented by objective measures such as statistical confidence intervals or by subjective measures based on narrative descriptions of the risk (e.g., expert opinion obtained in focus group settings). The version of the BCPR reviewed by this committee does not include any expression of uncertainty either in terms of reported confidence intervals or in narrative discussion. The committee was informed that NASA is working at this time to establish confi-

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report dence bands and acceptable levels of risk so that it can communicate such information to the research and operations communities. The committee has observed that the risks identified in the BCPR occur within the context of a larger set of risks to the human space flight program and to NASA as an organization. Highly visible failures, such as the loss of the space shuttles Challenger and Columbia, have the potential to erode public confidence in, and congressional support for, human space flight and for NASA as an agency. Under certain circumstances, the presidential initiative announced in January 2004 could add an additional risk: that of pressure being applied to achieve the goals of the initiative without sufficient time or resources for adequate preparation, which could compromise mission safety. Pressure can increase when critical biomedical research is delayed by a disaster-related response, such as the one that occurred after the loss of the Challenger. The single most substantial organizational risk that NASA faces may be the possibility that a thoughtfully conceived critical path roadmap could be pre-empted or abandoned as a result of such pressures or of an abrupt change in policy direction. STRENGTHS AND WEAKNESSES OF THE BCPR The BCPR is a broad and complex document, one that has been developed with care and thought. NASA has sought internal and external expert opinion to evaluate and refine the risks and the critical research questions that are associated with those risks. One of the strengths of the BCPR is its breadth of coverage. The discipline areas identified in the roadmap are broad—for example, the area of human health and countermeasures includes bone and muscle loss, neurovestibular adaptation, cardiovascular and immunological changes, and environmental effects. Advanced human life support comprises food and life support systems, environmental monitoring and control systems, and extravehicular activity technologies and the human factors related to these technologies. However, grouping risks into broad discipline areas can result in uneven attention being focused across topics. For example, some areas, such as bone loss in the Human Health and Countermeasures area, have received considerable attention and investigation, whereas others, such as the psychological and physical impacts of stress on crew performance in the Behavioral Health and Performance area, have not been adequately addressed. In the area of Advanced Human Support Technologies (AHST), NASA faces challenges that may be divided into two areas: (1) the determination

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report of optimal technology and (2) the engineering development and qualification of the hardware, software, and operational procedures required to realize the systems performance of the selected technology. Determining the optimal technology involves interrelated studies within the physical, chemical, and biological sciences, and frequently builds on accumulated experience. Reliance on mechanical systems that are subject to degradation and breakdown underscores the need for engineering to effectively engage with other disciplines to ensure that all relevant human factors are properly evaluated. In the context of long-duration missions, ensuring highly reliable performance of technologies will depend on two principal means of verification: stress testing and full duration life testing. In the first approach, relevant environmental factors are made more stressful (e.g., hotter/colder than normal) to permit evaluation of long-term performance in a short period of time. The “full duration” approach is to build the apparatus and operate it within normal limits for an extended period of time—preferably several times the actual requirement. Coupled with failure analysis and remediation, the full duration approach gives the greatest confidence. To accomplish this sort of qualification with advanced life support systems, accumulated operational experience with such systems or their immediate predecessors is necessary.2 To respond to these and other challenges, NASA has sought feedback from scientific researchers, operational managers, and administrators; examined the value and implications of research involving crews in analogous environments, such as the Antarctic or submarines; and explored the applicability of findings from animal models. NASA also has initiated efforts to understand the implications of small sample size on space-related research. Such efforts are appropriate for the efficient design of a research program that supports long-term, long-distance space flight. NASA’s commitment to external review and expert advice is evidenced by its request for the current study as well as other related reviews by the National Academies (see Appendix C). The committee’s final report will include a summary of the recommendations from these previous reports that remain relevant to the current study. 2   The Russian-built Elektron oxygen generator is a case in point. A U.S.-designed and built system using more advanced technology awaits launch in mid-2008. The United States is engaged in adapting the Russian system rather than using the intervening time to qualify the U.S. apparatus.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report Risk Identification NASA’s decision to rely on expert opinion in identifying and ranking risks is a reasonable strategy, given the broad array of topics addressed in the BCPR. Expert opinion in health care and the life sciences is influenced both by systematically derived data and by heuristics, or “rules of thumb,” that are derived from personal and group experience. In a cautionary note, the committee observes that several factors contribute to the complexity of the issues that the BCPR addresses, including the number of identified risks, the heterogeneity of risk types, and the interdependence among risks. Risks range from theoretical concerns, such as virus-induced lymphomas and leukemias, to practical issues, including nutrition, motion sickness, and bone and muscle loss. In addition, some risks are specific (e.g., renal stone formation), whereas others are general (e.g., ambulatory care). Further external review may assist NASA in evaluating and prioritizing risks. Inclusion of Operational Priorities Many stakeholders with diverse points of view have contributed to the BCPR. To scientists, it is a research agenda for investigator-initiated projects that will advance the knowledge base of science. To NASA’s line managers, it is a set of operational challenges to be addressed to support the proposed missions to the International Space Station, the Moon, and Mars. The committee concludes that in order to further refine and focus the goals of the BCPR, NASA should label risks according to their relevance to operational requirements and according to temporal urgency—or the timeliness of countermeasure development—notably as related to medical operations. To be included meaningfully in the decision making process, biomedical countermeasures and life support technologies must be validated well in advance of the final integrated mission architecture. The committee further concludes that the identification of operational priorities requires the active and ongoing collaboration and exchange of perspectives among the key stakeholders (e.g., line managers, clinicians, researchers, and astronauts) in the human exploration of space. Sample Size Considerations A subject sample size of 10 imposes significant limitations on the information that can be obtained from the resulting data sets. Specifically,

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report very small sample size makes it impossible to state findings within reasonable confidence intervals, or to compare alternatives using tests of statistical significance. The committee recognizes that health-related studies based on observations of space mission crews will, for the foreseeable future, suffer from small sample size, and consequently inferences based on single missions will have inadequate statistical power. Hence, the committee does not propose that crew size be dictated by the requirements for statistical power. The committee proposes that, rather than rely on data from a single mission for inference, NASA could use two techniques to analyze data pooled from several missions. Drawing on the findings of the 2001 NAS report, Small Clinical Trials,3 the committee suggests the following: (1) a Bayesian sequential trials approach4 and (2) hierarchical random or fixed effects methods to account for variation across missions.5 Specifically, for the Bayesian sequence of studies approach, the committee proposes that studies be designed to incorporate as many missions as possible, somewhat in the manner of sequential clinical trials, and also that they incorporate prior information from archival data and ground-based studies to the extent practicable. In a Bayesian framework, a prior uncertainty distribution for degree of mineral bone mass loss as a function of age, sex, and time in space, for example, would be incrementally modified by new information gained from, and incidental to, a series of missions. The goal would be to develop a sequence of posterior distributions about the quantity of interest, the latest of which would always summarize the current accumulated information. For effective pooling, at least in terms of the hierarchical modeling analysis, a number of consistency issues need to be addressed. For example, consistency is needed across the pooled missions in terms of what is measured and the frequency of longitudinal measurements. Small Clinical Trials provides a discussion of such modeling (IOM, 2001:67–70). With good planning and execution and some consideration of these issues, the resulting data should be suitable for such hierarchical methods. 3   See page 14 of Small Clinical Trials for an example of pooling of data across missions. 4   See pages 72–73 of Small Clinical Trials for a discussion of Bayesian methods in this context. 5   See pages 67–70 of Small Clinical Trials for a discussion of hierarchical methods in this context.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report Understanding the Interactions Among Risks The committee notes with approval that NASA has identified five cross-cutting risk areas (human health and countermeasures, radiation health, behavioral health and performance, autonomous medical care, and advanced human life-support technologies) and suggests that these cross-cutting areas deserve further attention. Notably, the committee suggests that crew health is an important driver of engineering design requirements. For risk reduction and management in human space flight, important factors include the interactions and interrelationships among risks, the sequence of risks, and the resultant cumulative risk. Design reference missions are used by many groups within NASA for planning and operations. To be most useful to NASA, design reference missions could be better defined by inclusion of additional relevant information to help the BCPR’s intended audience assess the overall system design and biomedical countermeasure requirements. An example for the ISS mission might be the estimated evacuation time for medical emergencies; for a month-long lunar mission, knowing the availability of powered surface locomotion, or whether the base is mobile or “buried” for radiation shielding would be important. For the 30-month mission to Mars, the ratio of orbital period to surface stay time, the cultural diversity of the crew, and the level of electrical power available are relevant considerations. To better understand interactions among risks, the design reference missions could be developed using “straw man” techniques, for example, to compare a Mars mission that orbits the planet affording no “real” gravity to a Mars mission wherein the crew lived on the surface for several months in one-third “g” (gravity). The former mission description would more strongly indicate the need for centrifugally induced “artificial gravity” than the latter. Importantly, up-to-date human factors engineering requirements could be applied to straw man missions, facilitating assessment of the nature and location of shortcomings. Under the rubric of human behavior and performance issues, NASA could examine interactions among risks by focusing on the full dimensions of human performance failure, including (1) intrapersonal factors, such as personality and coping styles; (2) interpersonal factors, such as attitudes toward cooperation and conflict; and (3) organizational factors, including the cultural and value systems of the participating national space agencies and contractors. The physiological response to stress also includes hormonal changes that influence human performance and affect cardiovascular health,

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report immune system function, and other risk areas identified in the BCPR. Attention to the complexities of human behavior and performance issues would strengthen the BCPR. Risk Assessment and Communication The committee has identified aspects of risk reduction and management that require further attention in the BCPR, including methods of communication that would support the full range of BCPR stakeholders, notably NASA medical operations personnel, investigators, and astronauts, and the need for a more comprehensive analysis of risk, including its identification, assessment, estimation, and evaluation. Communication of risk, including the response to accidents and disaster, is an important element of the BCPR. Methods of information communication that could enhance the usefulness of the BCPR include the following: levels of supporting evidence for each risk; evidence supporting the selection of enabling questions for each risk; information about the interaction and interrelations among risks; confidence intervals for quantitative data, and narrative comments about the strength of qualitative conclusions; information about how both qualitative and quantitative data were derived; and a glossary. Although final policy decisions about risk must be simple—for example, “go” or “no-go”—and the visual metaphor of stoplight colors in the BCPR is appealing in this context, the committee concludes that the assignment of risks to red, yellow, or green status has pushed this simplification down to a point that occurs too early in the risk-analysis process. Final, simplistic decisions should be made only after a thorough analysis of the risk factors has been conducted at the more fundamental levels. Specific problems associated with the stoplight chart include the following: a given color designation has numerous possible (disparate) paths; multiple and varying dimensions are reflected in each color designation, including the severity and probability of occurrence; there is an absence of threshold values and consistent information

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report about confidence intervals or the robustness of the data that support specific risk considerations; the dimension of time is not factored properly into risk assessment in the BCPR. This prohibits analysis of the impacts of long-distance space flight on crew health and life support systems, prioritization of risks, and assessment of countermeasure readiness; and the design reference missions (DRMs) are inadequately defined in terms of data and information that are relevant to the diverse users of DRMs. The committee observes that risks are not expressed in the BCPR in the format of the NASA-wide Continuous Risk Management system,6 even though the systemwide use of this format is well understood by NASA personnel and would be an effective way of communicating the elements of the BCPR throughout the organization. NASA developed the Continuous Risk Management System in 1996 to help project managers continuously identify, analyze, and manage risk throughout the life-cycle of a project and for use as a proactive tool for managers to monitor resource allocation and ensure that critical project milestones are achieved within acceptable levels of risk. The use of the Continuous Risk Management system results in a set of actionable risks that can be assessed with regard to the probability and consequences of occurrence. This information can be used to plan mitigation measures indicating that all risks have been reduced to “green” by the projected launch date, to inform cost–benefit analyses and prioritization efforts, and to help NASA obtain adequate resources (funding, time, expertise) to carry out these measures. The importance of evaluating the timeliness of research and countermeasure and system development is illustrated by the needs of the Mars Design Reference Mission, for which the lack of a qualified life support system will be more critical in 2020 than it is today. Risks could be formulated using the straw man techniques described above to evaluate the selection of habitat and pressure suit atmospheres. This would eliminate the need for testing new and optimum pre-breathe protocols and allow NASA 6   For more information on NASA’s Continuous Risk Management system, see http://satc.gsfc.nasa.gov/support/ASM_FEB99/crm_at_nasa.html.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report to address more tractable questions about the effects of prolonged living in selected cabin atmospheres. Because design and countermeasure readiness milestones must significantly precede mission launch milestones, acknowledgment that time is an important dimension of risk implies recognition of the specific link between the date that a validated countermeasure is needed and the actual mission launch target date. Risk Areas Meriting More Attention The committee has identified risk areas in the BCPR that deserve further attention from NASA, including the following: psychological and physical impacts on the ability to perform, including crew selection criteria (social, demographic, and pre-existing health status of astronauts and their response to stress), especially in the context of longer term missions; radiation effects; nutrition; autonomous medical care and self-care, including telerobotic surgery, especially in the context of longer term missions; and environmental factors associated with long-term missions, such as analyses of air and water quality and cabin and extravehicular activities pressure. PRELIMINARY CONCLUSIONS To assess the quality of the science that forms the basis for decision making in the BCPR, users of the document must be able to distinguish risks and countermeasures that have been identified using (1) heuristics (rules of thumb) versus scientific investigation (evidence based), (2) data derived from analog environments versus those obtained from in-flight experience, and (3) data derived from human versus animal studies. As a result of the President’s space exploration initiative, NASA has proposed a schedule that requires considerable resources, notably time and upfront funding. Safety and mission effectiveness may be compromised if the necessary resources are not authorized or allocated promptly. To the technical risks of space flight the President’s initiative has added the organizational risk that elements of the BCPR might be compromised in an effort to meet a societal goal.

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report Time is an important dimension of risk, particularly in the context of long-duration space flight, such as the 30-month Mars mission outlined in the President’s initiative. Lack of attention to the dimension of time makes it difficult to identify risk priorities and determine countermeasure readiness, predict the maintainability of systems and equipment, and understand the impact of space flight on crew health over time. Health-related studies based on observations of crew members always will suffer from small sample size. Consequently, any inferences based on single missions will have inadequate statistical power. Methods are available to address this problem, including the pooling of data from multiple studies or missions in the manner of sequential clinical trials and Bayesian sequential trials. Standard procedures are needed for incorporating the results of ongoing research into the calibration of risk, including the development of mechanisms for updating risk assessment and the establishment of exit criteria for risks for which adequate mitigation measures have been developed. The long time frame of the space initiative makes it likely that new knowledge and technologies will need to be incorporated into the BCPR. A structure that provides focus and attention throughout the agency and at the same time clearly identifies the “owner and manager” of the BCPR will help assure that it remains a dynamic document over the coming decades. Human factors are a high priority in space engineering design, especially in an era of planetary exploration. Linking human factors with engineering perspectives in the BCPR is important for the development of countermeasures, for example, for musculoskeletal weakness upon arrival in a gravitational environment after long-duration space flight, control of radiation exposure, and identification of coping skills and preventive measures to respond to the stresses of prolonged space flight. Analog environments, notably polar expeditions in the Arctic and Antarctic, high-altitude exploration, undersea exploration, and space simulation studies, provide a wealth of data and information that could be further incorporated into the BCPR to make the current analyses more robust. In summary, the current BCPR is a solid beginning for the further understanding, management, and mitigation of the risks associated with longer duration space flight. However, additional refinement and development is required to take full advantage of current evidence regarding these risks and to develop a focused and prioritized plan for their mitigation to

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Preliminary Considerations Regarding NASA’s Bioastronautics Critical Path Roadmap: Interim Report the crew, the mission, the program, the agency, and the national image associated with space flight. This could lead to the development of a management tool that will guide NASA leadership in assigning the operational and research priorities that will be required prior to future lunar and Mars missions. NEXT STEPS The IOM committee plans to engage in information collection efforts over the next 11 months in order to provide NASA with recommendations about risk communication and about the assessment, management, and implementation of the BCPR with respect to bioastronautics research for the missions contemplated in the President’s exploration initiative. The committee’s work will include a visit to the Johnson Space Center, other meetings with NASA personnel, other NASA decision makers, and those in operational areas related to the human space flight program, and analysis of testimony from a wide range of experts in the areas of bioastronautics and risk assessment. The final report will be issued in August 2005. WORKS CITED IOM (Institute of Medicine). 2001. Small Clinical Trials. Evans, C.H., Ilstad, S.T., eds. Washington, DC: National Academy Press. NASA (National Aeronautics and Space Administration). 2004. Bioastronautics Critical Path Roadmap: An Approach to Risk Reduction and Management for Human Space Flight. Houston, TX: Lyndon B. Johnson Space Center.

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