Summary

Since its inception, the U.S. human spaceflight program has grown from launching a single man into orbit to an ongoing space presence aboard the International Space Station (ISS) with partners from many nations. Human spaceflight inherently involves a high degree of risk during all phases of any space mission, including terrestrial training and vehicle testing, launch, inflight during the mission, and landing. Health risks during long duration and exploration spaceflights include short-term health consequences (e.g., nausea or fatigue from acute radiation exposure during a solar storm, injury, blurred vision), as well as long-term health consequences that arise or continue months or years after a flight (e.g., radiation-induced cancers, loss of bone mass). Long duration and exploration spaceflights (including extended stays on the ISS or exploration missions to an asteroid or Mars) will likely expose crews to levels of known risks beyond those allowed by current health standards, as well as to a wide range of risks that are poorly characterized, uncertain, and perhaps unforeseeable.

The National Aeronautics and Space Administration (NASA) asked the Institute of Medicine (IOM) to develop an ethics framework and to identify principles to guide decision making about health standards for long duration and exploration class missions “when existing health standards cannot be fully met” or adequate standards cannot be developed based on existing evidence (see Box S-1). The committee was not asked to review NASA’s risk management processes.

To respond to its statement of task, the IOM convened the Committee on Ethics Principles and Guidelines for Health Standards for Long Duration and Exploration Spaceflights. This report provides the committee’s recommendations on ethics principles, responsibilities, and a decision framework to guide decisions about the application of health standards to long duration and exploration spaceflights. The recommendations include many components that NASA has considered or is already implementing in its work on health standards for spaceflight. However, the adoption of the recommended ethics principles and responsibilities and decision framework not only introduces new processes and responsibilities but also alters the context in which existing components operate.

HEALTH STANDARDS FOR HUMAN SPACEFLIGHT

The use of health standards to protect individuals engaged in specific types of work or activities is not unique to space exploration. Health standards are used throughout occupational settings to protect workers and guide design, research, and engineering efforts, among other purposes. The committee examined various high-risk occupations and activities and identified some common factors (such as types and severity of risk; types and distribution of potential risks and benefits; activity purpose; and the presence of independent oversight) that aided the committee’s deliberations. However, the committee was not able to identify existing ethics frameworks or decision-making models for specific occupations that were directly and wholly applicable to decisions about health standards for long duration and exploration spaceflight.

As the federal agency with institutional responsibilities to conduct and evaluate a wide range of spaceflight missions, NASA addresses health risks associated with spaceflight using a number of strategies, including engineering, design, mission planning, basic and clinical research, surveillance and medical monitoring, preventive and treatment countermeasures, and health standards. NASA’s crew health standards consider three categories of preflight, inflight, and postflight health issues: fitness-for-duty standards, permissible exposure limits, and permis-

sible outcome limits. Additionally, NASA has health standards relevant to human factors, habitability, and environmental health.

If a human spaceflight mission cannot meet current health standards, or if inadequate information exists to revise a health standard, the options, as identified and examined by the committee, would be to: (1) liberalize the NASA health standards, (2) establish more permissive “long duration and exploration health standards,” or (3) grant an exception to the standard in order to conduct these missions before new protective technologies and strategies are available or additional data are acquired which may allow revision of the standard. The committee found the first two options to be unacceptable when evaluated against the ethics principles and responsibilities described in this report.

The committee finds relaxing (or liberalizing) current health standards to allow for specific long duration and exploration missions to be ethically unacceptable. Current NASA policy outlines the administrative processes and levels of approval required to initiate a new health standard or revise a current health standard. NASA’s health standards “are based on the best available scientific and clinical evidence, as well as operational experience.” Moreover, review of health standards occurs every 5 years or can be triggered any time that new research data or clinical observations indicate an update may be necessary. Modifying health standards outside of this established process merely to permit long duration and exploration missions would be arbitrary.

The second option maintains current health standards for all missions except long duration and exploration spaceflight, which would have a separate set of health standards. This approach presumably would entail setting a more permissive ceiling on allowable risk for long duration and exploration missions under conditions in which existing evidence and knowledge make it nearly impossible to quantify those ceilings. The committee found this approach wanting, lacking a clear and compelling justification for why acceptable risks and levels of uncertainty should be greater for long duration and exploration missions than other human spaceflight missions.

Having excluded the options of modifying existing standards or creating a separate set of standards, the committee concludes that the only ethically acceptable option that could allow for increased risk exposures in the context of long duration and exploration spaceflights is granting an exception to existing health standards. The committee believes that exceptions to health standards should be considered on a mission-by-

mission basis and used in very limited circumstances following the ethics-based framework recommended.

When making decisions about whether to allow risk levels that do not meet NASA’s current health standards, it is important that current health standards reflect the most relevant and up-to-date evidence about spaceflight-related risks to human health and safety. Although NASA has formal policies for health standard initiation and revision, the committee believes additional information about decision criteria, process, and application of ethics principles should be available to the public.

Recommendation 1: Expand on the Policies for Initiating and Revising Health Standards

NASA should ensure that its policies regarding health standards detail the conditions or circumstances (and relevant priorities) that initiate development or revision of health standards and explicitly indicate how these policies are fully consistent with the set of ethics principles outlined in this report.

ETHICS PRINCIPLES

Over the course of centuries, philosophers have debated the relative merits and shortcomings of the major theories of western moral and political philosophy: utilitarianism, duty-based approaches, virtue-based theories, and others. One successful approach to avoiding the need for a single ethical theory is to focus on mid-level principles rather than the theory to which they belong or from which they are derived. This approach has proven to be particularly successful when used by expert committees or commissions made up of individuals with diverse commitments in an effort to find common ground on how best to approach challenging ethical issues in the context of public policy. The committee adopted a principle-based approach in recognition of its accessibility and applicability for its task.

Recommendation 2: Apply Ethics Principles to Health Standards Development and Implementation
NASA should apply the following ethics principles in the development and implementation of its health standards for decisions regarding long duration and exploration spaceflights:

• Avoid harm—the principle includes the duty to prevent harm, exercise caution, and remove or mitigate harms that occur. Thus, NASA should exhaust all feasible measures to minimize the risks to astronauts from long duration and exploration spaceflights, including addressing uncertainties through approaches to risk prevention and mitigation that incorporate safety margins and include mechanisms for continuous learning that allow for incremental approaches to risk acceptance.
• Beneficence—the principle to provide benefit to others. NASA should consider in its decision making the potential benefits of a specific mission, including its scientific and technological importance, as well as its potential beneficiaries including current and future astronauts and members of society at large.
• Favorable balance of risk and benefit—the principle to seek both a favorable and acceptable balance between the risk of harm and potential for benefit. In authorizing long duration and exploration activities and in approving particular missions, NASA should systematically assess risks and benefits and the uncertainties attached to each, drawing on the totality of available scientific evidence, and ensuring that benefits sufficiently outweigh risks.
• Respect for autonomy—the principle to ensure that individuals have both the right to self-determination and processes in place to exercise that right. NASA should ensure that astronauts are able to exercise voluntariness to the extent possible in personal decision making regarding participation in proposed missions, that they have all available information regarding the risks and benefits of the proposed mission, and that they continue to be apprised of any updates to risk and benefit information throughout the mission.
• Fairness—the principle requires that equals be treated equally, that burdens and benefits be distributed fairly, and that fair processes be created and followed. NASA’s decision making surrounding missions should explicitly address fairness, including the distribution of the risks and benefits of the mission, crew selection, and protections for astronauts after missions.

• Fidelity—the principle recognizes that individual sacrifices made for the benefit of society may give rise to societal duties in return. Given the risks that astronauts accept in participating in hazardous missions, NASA should respect the mutuality of obligations and ensure health care and protection for astronauts not only during the mission but after return, including provision of lifetime health care for astronauts.

ETHICS-BASED RESPONSIBILITIES

Acting on ethics principles creates specific responsibilities that apply to individuals and organizations engaged in particular activities. NASA, as an employer, a federal agency responsible for innovation and exploration, a research sponsor, and an international partner, has moral obligations to formally recognize and act on responsibilities that logically flow from the ethics principles outlined in Recommendation 2. Specifically, the ethics principles need to be incorporated into decisions about whether risks in excess of those allowed under current health standards are acceptable and, if so, what conditions must be satisfied to engage in ethically acceptable long duration and exploration class missions. These decisions are further influenced by the limitations imposed by costs, time lines, and technological feasibility.

Recommendation 3: Implement Ethics Responsibilities
NASA should adopt policies or processes that formally recognize the following ethics responsibilities related to health standards for long duration and exploration spaceflights:

• Fully inform astronauts about the risks of long duration and exploration spaceflights and make certain that the informed decision-making process is adequate and appropriate.
• Adhere to a continuous learning strategy (including health surveillance and data collection) to ensure that health standards evolve and improve over time and are informed by data gained before, during, and after long duration and exploration spaceflights, as well as from other relevant sources.

• Solicit independent advice about any decision to allow any specific mission that fails to meet NASA health standards or any decision to modify health standards.
• Communicate with all relevant stakeholders (such as astronauts and the public at large) the rationale for, and possible impacts (including harm type, severity, and probability estimates) related to any decision about health standards in a procedurally transparent, fair and timely manner, providing adequate opportunity for public engagement.
• Provide equality of opportunity for participation in long duration and exploration spaceflights to the fullest extent possible. For example, fairness in crew selection means that NASA should accept some group differences in population risk in order to create equality of opportunity to participate in missions, and accommodate individual variance from population-based risk estimates to the extent that individual differences do not jeopardize mission operations.
• Provide preventive long-term health screening and surveillance of astronauts and lifetime health care to protect their health, support ongoing evaluation of health standards, improve mission safety, and reduce risks for current and future astronauts.
• Develop and apply policies that appropriately and sufficiently protect the privacy and confidentiality of astronaut health data.

AN ETHICS-BASED DECISION FRAMEWORK

In assessments of long duration and exploration spaceflights that are unlikely to meet current health standards, NASA can facilitate its planning by structuring decision making in a three-step process (see Box S-2). The first and broadest decision (Level 1) is whether, and under what conditions, any missions that are unlikely to meet current health standards are ethically acceptable. If NASA decides that missions that fail to meet existing health standards are not acceptable, then such missions must be deferred until new knowledge about risk or uncertainties or risk mitigation strategies are available.

If NASA decides that exceptions to existing health standards are ethically acceptable, NASA must then decide what process and criteria should be applied to determine whether a specific mission should be granted an exception. Based on the ethics principles identified, criteria for reviewing exception requests could include requirements that the proposed mission

• be expected to have exceptionally great social value;
• have great time urgency;
• have expected benefits that would be widely shared;
• be justified over alternate approaches to meeting the mission’s objectives;
• establish that existing health and safety standards cannot be met;
• be committed to minimizing harm and continuous learning;
• have a rigorous consent process to ensure that astronauts are fully informed about risks and unknowns, meet standards of informed decision making, and are making a voluntary decision; and
• provide health care and health monitoring for astronauts before, during, and after flight and for the astronaut’s lifetime.

An ethically acceptable process to grant exceptions would also be evidence-based, transparent, and solicit independent advice. The committee emphasizes that exceptions should only be granted in rare circumstances and should increase the responsibilities for NASA and society.

The second decision level (Level 2) is whether a specific, contemplated mission that is unlikely to meet current health standards is ethically acceptable. This requires evaluating whether the mission fulfills the conditions articulated in Level 1. Whereas Level 1 could be a one-time decision by NASA that affects all long duration and exploration missions,¹ Level 2 decisions would be made on a mission-by-mission basis.

Once a specific mission is deemed ethically acceptable, the third level (Level 3) of decision making involves identification of the crew for the mission given the mission’s requisite skills and expertise, the astronauts’ health susceptibilities and personal risk factors (if known), and an individual astronaut’s informed decision to participate. Level 3 includes decisions by both NASA and individual astronauts.

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¹It is important to note that this decision may be revisited by NASA but should adhere to the same ethics-based decision framework to justify any alterations.

Recommendation 4: Adopt an Ethics-Based Decision Framework NASA should apply the relevant ethics principles and fulfill the concomitant responsibilities through a three-level, ethics-based decision framework that examines

• Level 1: Decisions about allowing risk to astronaut health and safety in excess of that permitted by health standards,
• Level 2: Decisions about undertaking specific missions, and
• Level 3: Decisions concerning individual astronaut participation and crew composition.

CONCLUDING REMARKS

From its inception, human spaceflight has pushed the boundaries of acceptable health and safety risks for astronauts. NASA, its international partners, and commercial space ventures will continue to face complex ethical decisions about risk acceptability as technologies improve and longer and more distant spaceflights become feasible. The ethics framework outlined in this report builds on the work of NASA and others and identifies a set of recommendations for ethically assessing and responding to the challenges associated with health standards for long duration and exploration spaceflight. Establishing and maintaining a firmly grounded ethics framework for this inherently risky activity is essential to guide NASA’s decisions today and to create a strong foundation for decisions about future challenges and opportunities.