Public Release: 

An ethics framework should be used to decide health standards for extended, exploratory spaceflights

National Academies of Sciences, Engineering, and Medicine

WASHINGTON - NASA should use an ethics framework when deciding whether, and under what conditions, spaceflights that venture outside low Earth orbit or extend beyond 30 days are acceptable if they do not meet current health standards, says a new report from the Institute of Medicine, the health arm of the National Academy of Sciences. Exceptions to existing health standards should be granted by NASA on a mission-by-mission basis, and any exceptions should be rare and occur only in extenuating circumstances. The report provides an ethics framework based on six principles and related ethics responsibilities to guide NASA's decision making for such missions. The committee that wrote the report did not make conclusions or recommendations about the value or advisability of future human spaceflight, the prioritization of NASA activities, or the appropriate level of funding NASA should receive to support human spaceflight activities.

For any mission, NASA has to make numerous decisions that balance mission necessity against health and safety risks for the crew, technological feasibility, and financial costs. The possible health risks -- such as vision impairments, bone demineralization, radiation exposure, and impact on behavior -- vary from mission to mission. Long duration and exploration spaceflights, including extended stays on the International Space Station and trips to Mars, will likely expose crews to increased risks. As part of its risk management process to protect the health and safety of astronauts, NASA has adopted standards to provide a healthy and safe environment before, during, and after all flights. The committee stressed that NASA's policies to initiate and revise health standards should reflect the most relevant and up-to-date evidence, but recommended that NASA explicitly indicate how these policies are consistent with the ethics principles described in the report.

"From its inception, space exploration has pushed the boundaries and risked the lives and health of astronauts," said chair of the committee Jeffrey Kahn, Levi Professor of Bioethics and Public Policy, Johns Hopkins Berman Institute of Bioethics, Baltimore. "Determining where those boundaries lie and when to push the limits is complex. NASA will continue to face decisions as technologies improve and longer and farther spaceflights become feasible. Our report builds upon NASA's work and compiles the ethics principles and decision-making framework that should be an integral part of discussions and decisions regarding health standards for long duration and exploration spaceflight."

The committee provided a three-level framework that NASA should follow to make decisions about long duration and exploration spaceflights that are unlikely to meet current health standards. The first decision level requires NASA to decide whether it is acceptable to risk astronaut health and safety for missions that could exceed the health standards. If NASA decides such missions are ethically acceptable, it must then determine the process and criteria for granting exceptions. The second decision level has NASA determine whether a specific mission that is unlikely to meet health standards is ethically acceptable. If a mission is deemed ethically acceptable, the third decision level focuses on the selection of the crew for the mission and an astronaut's decision to participate on that mission.

Within each of the framework's levels are ethics principles that should help guide decisions.

  • Avoid harm by preventing harm, exercising caution, and removing or mitigating harms that occur.
  • Provide benefits to society.
  • Seek a favorable and acceptable balance of risk of harm and potential for benefit.
  • Respect autonomy by allowing individual astronauts to make voluntary decisions regarding participation in proposed missions.
  • Ensure fair processes and provide equality of opportunity for mission participation and crew selection.
  • Recognize fidelity and the individual sacrifices made for the benefit of society, as well as honor societal obligations in return by offering health care and protection for astronauts during a mission and over the course of their lifetimes.

The committee also recommended that NASA recognize a set of ethical responsibilities derived from the above ethics principles when considering the health standards for long duration and exploration spaceflights. Some of the responsibilities include to:

  • ensure fully informed decision making by astronauts regarding the risks of long duration and exploration spaceflights;
  • solicit independent advice regarding health standards for these missions;
  • adhere to a continuous learning strategy so health standards evolve and improve over time;
  • communicate with all relevant stakeholders in a procedurally transparent, fair, and timely manner the rationale for, and possible impacts related to, any decision about health standards;
  • provide equality of opportunity for participation in long duration and exploration missions;
  • require preventive long-term health screening and surveillance of astronauts and lifetime health care; and
  • develop and apply policies that protect the privacy and confidentiality of astronaut health data.


The study was sponsored by NASA. Established in 1970 under the charter of the National Academy of Sciences, the Institute of Medicine provides independent, objective, evidence-based advice to policymakers, health professionals, the private sector, and the public. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. A committee roster follows.


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Pre-publication copies of Health Standards for Long Duration and Exploration Spaceflight: Ethics Principles, Responsibilities, and Decision Framework are available from the National Academies Press on the Internet at or by calling 202-334-3313 or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).


Board on Health Sciences Policy

Committee on Ethics Principles and Guidelines for Health Standards for Long Duration and Exploration Spaceflights

Jeffrey Kahn, M.Ph., Ph.D. (chair)
Levi Professor of Bioethics and Public Policy
Berman Institute of Bioethics
Johns Hopkins University

Nancy E. Conrad
Founder and Chair
The Conrad Foundation
Washington, D.C.

Peter F. Demitry, M.D.
4D Enterprises LLC
Haymarket, Va.

Bonnie J. Dunbar, Ph.D., M.S.
M.D. Anderson Professor of Mechanical and Biomedical Engineering
STEM Center
University of Houston
Seabrook, Texas

Barbara J. Evans, Ph.D., L.L.M., J.D.
Professor of Law and George Butler Research Professor, and
Director of the Center on Biotechnology and Law
University of Houston Law Center

Bernard A. Harris Jr., M.D., M.S.
CEO and Managing Director
Vesalius Ventures

David G. Hoel, Ph.D.
Distinguished University Professor
Department of Biostatistics, Bioinformatics, and Epidemiology
Medical University of South Carolina

Jonathan Kimmelman, Ph.D.
Associate Professor in Biomedical Ethics
Biomedical Ethics Unit
McGill University

Anna C. Mastroianni, J.D., M.Ph.
Assistant Professor
Institute for Public Health Genetics
University of Washington School of Law

Lawrence A. Palinkas, Ph.D., M.A.
Albert G. and Frances Lomas Feldman Professor of Social Policy and Health
School of Social Work
University of California, San Diego
Los Angeles

Carol E.H. Scott-Conner, Ph.D., M.D., M.B.A.
Professor of Surgery
Department of Surgery
University of Iowa Hospitals and Clinics
Iowa City

Michael A. Silverstein, M.D., M.Ph.
Clinical Professor
Environmental and Occupational Health
University of Washington School of Public Health

Ronald E. Turner, Ph.D., M.S.
Distinguished Analyst
ANSER (Analytic Services Inc.)
Arlington, Va.

R. Leonard Vance, J.D.
School of Engineering
Department of Mechanical Engineering Virginia Commonwealth University

Gregory R. Wagner, M.D.
Senior Adviser to the Director
National Institute for Occupational Safety and Health
Washington, D.C.


Catharyn T. Liverman
Co-Study Director

Margaret A. McCoy
Co-Study Director

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