and Astronaut Health
Managing and Communicating Cancer Risks
Committee on Assessment of Strategies for Managing Cancer Risks
Associated with Radiation Exposure During Crewed Space Missions
Board on Health Sciences Policy
Board on Health Care Services
Health and Medicine Division
Nuclear and Radiation Studies Board
Division on Earth and Life Studies
A Consensus Study Report of
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This activity was supported by a contract between the National Academy of Sciences and the National Aeronautics and Space Administration. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.
International Standard Book Number-13: 978-0-309-47966-0
International Standard Book Number-10: 0-309-47966-5
Digital Object Identifier: https://doi.org/10.17226/26155
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2021. Space radiation and astronaut health: Managing and communicating cancer risks. Washington, DC: The National Academies Press. https://doi.org/10.17226/26155.
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COMMITTEE ON ASSESMENT OF STRATEGIES FOR MANAGING CANCER RISKS ASSOCIATED WITH RADIATION EXPOSURE DURING CREWED SPACE MISSIONS
HEDVIG “HEDI” HRICAK (Chair), Chairman, Department of Radiology, Memorial Sloan Kettering Cancer Center
R. JULIAN PRESTON (Vice Chair), Special Government Employee (Expert), Radiation Protection Division, U.S. Environmental Protection Agency
AMY BERRINGTON DE GONZÁLEZ, Branch Chief and Senior Investigator, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health
ANN BOSTROM, Weyerhaeuser Endowed Professor in Environmental Policy, Daniel J. Evans School of Public Policy and Governance, University of Washington, Seattle
CASEY CANFIELD, Assistant Professor of Engineering Management and Systems Engineering, Missouri University of Science and Technology
HARRY M. CULLINGS, Consultant, Radiation Effects Research Foundation
LAWRENCE T. DAUER, Attending Physicist, Memorial Sloan Kettering Cancer Center
BERNARD A. HARRIS, JR., Chief Executive Officer, Vesalius Ventures
ALEJANDRA HURTADO DE MENDOZA, Assistant Professor, Georgetown University
JEFFREY KAHN, Andreas C. Dracopoulos Director, Johns Hopkins Berman Institute of Bioethics
GUILLERMINA LOZANO, Hubert L. Olive Stringer Distinguished Chair in Oncology, Professor and Chair, Department of Genetics, The University of Texas MD Anderson Cancer Center
GIOVANNI PARMIGIANI, Associate Director for Population Sciences, Dana Farber/Harvard Cancer Center; Professor, Department of Data Sciences, Dana-Farber Cancer Institute, and Department of Biostatistics, Harvard T.H. Chan School of Public Health
ROBERT L. SATCHER, Associate Professor, Orthopaedic Oncology, The University of Texas MD Anderson Cancer Center
CAROL SCOTT-CONNER, Professor Emeritus of Surgery, University of Iowa Carver College of Medicine
IGOR SHURYAK, Assistant Professor of Radiation Oncology, Center for Radiological Research
GREGORY R. WAGNER, Adjunct Professor of Environmental Health, Harvard T.H. Chan School of Public Health
GAYLE E. WOLOSCHAK, Professor, Department of Radiation Oncology, Feinberg School of Medicine, Lurie Comprehensive Cancer Center, Northwestern University
LYDIA B. ZABLOTSKA, Professor of Epidemiology, Salvatore Pablo Lucia Chair in Preventive Medicine, University of California, San Francisco
REBECCA ENGLISH, Study Director
OURANIA KOSTI, Senior Program Officer
LEAH CAIRNS, Program Officer
CLAIRE GIAMMARIA, Associate Program Officer (until May 2021)
RUTH COOPER, Research Associate (from January 2021)
CYNDI TRANG, Research Associate (until January 2021)
KENDALL LOGAN, Senior Program Assistant
MICHAEL K. ZIERLER, Science Writer
SHARYL NASS, Senior Director, Board on Health Care Services
ANDREW M. POPE, Senior Director, Board on Health Sciences Policy
This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report:
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions
or recommendations of this report, nor did they see the final draft before its release. The review of this report was overseen by ELI Y. ADASHI, Brown University, and JOE W. GRAY, Oregon Health & Science University. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
Understanding and mitigating the health effects of exposure to space radiation has challenged scientists and engineers for decades. While science has advanced our knowledge of the effects of radiation on the human body on land and in space, uncertainties remain regarding how best to assess, manage, and communicate radiation risks to those affected.
The present study—focused on space radiation and astronaut health—occurs at a time when plans are being developed for long-duration spaceflight missions beyond low Earth orbit to the Moon and Mars. These missions, particularly to Mars, could introduce health risks and challenges unlike others experienced by previous astronauts and their space agencies. Our study committee took on the task of providing advice to the National Aeronautics and Space Administration (NASA) on the space radiation health standard with enthusiasm and a sense of significance, as the implementation of the standard will have a measurable impact on astronaut health, opportunity for spaceflights, and overall mission viability.
The committee worked to develop this report in an objective manner based on the options and suggested approaches for updating the space radiation standard provided by NASA, available scientific evidence, and individual committee member expertise and knowledge. During this process we were specifically attendant to the considerable importance of the uncertainties and developing knowledge around radiation and cancer risks, as well as the uniquely complex and challenging mission of NASA. As astronaut Ellison Onizuka’s words are memorialized on the last page of every U.S. passport, “Every generation has the obligation to free men’s minds for a look at new worlds … to look out from a higher plateau than the last generation.”
NASA has many tools and resources for continued evaluation and reconsideration of health standards. It is the committee’s hope that this report provides an incremental step forward for NASA and its astronauts in the planning of space travel farther afield.
Hedvig “Hedi” Hricak, Chair
R. Julian Preston, Vice Chair
Committee on Assessment of Strategies for Managing Cancer Risks Associated with Radiation Exposure During Crewed Space Missions
The committee thanks the National Aeronautics and Space Administration (NASA) for sponsoring this study and engaging with the committee in public meetings and providing thoughtful, timely responses to the committee’s questions and requests for information throughout the study process. We are appreciative of NASA’s willingness to engage with external experts on a complex issue such as space radiation as the safety and success of space travel is of national interest. We especially thank NASA staff—David Francisco and Edward Semones—for providing a technical review of portions of this report describing NASA programs and processes. The committee is also grateful to members of the International Commission on Radiological Protection Task Group 115 on Risk and Dose Assessment for Radiological Protection of Astronauts—particularly presenters Marco Durante and Werner Rühm—for sharing information with the committee during the April 2021 public webinar on international space radiation dose limits. The speakers provided valuable information and perspectives on the complex work of considering standards for spaceflight across international agencies.
It was our great privilege to work with such dedicated committee members, each of whom thoroughly engaged in the study, generously shared their expertise, and contributed significant time and effort to this endeavor. This was a complex task, and the committee members truly stepped up to meet the challenge. Their reasoned and thoughtful discussions made this report possible.
We were all fortunate to work with a diligent and outstanding team of National Academies of Sciences, Engineering, and Medicine staff, and
we deeply thank Rebecca English, Ourania Kosti, Leah Cairns, Claire Giammaria, Ruth Cooper, and Kendall Logan, led by Sharyl Nass and Andrew Pope, senior board directors in the Health and Medicine Division. We also sincerely thank Michael Zierler for his thoughtful writing and editing work, Rebecca Morgan of the National Academies Research Center staff for her assistance with fact-checking the report, and Michael Berrios for his thoughtful Japanese-English translation.
Why NASA Is Considering Revisions to the Current Radiation Exposure Standard and Associated Risk Management
Committee’s Charge and Approach
2 SPACE RADIATION AND CANCER RISKS TO ASTRONAUTS
The Space Radiation Environment and Its Impact on Human Health
Factors Affecting Radiation-Induced Cancer Risk
The Current NASA Model for Estimating Cancer Risk
3 NASA’S SPACEFLIGHT RADIATION EXPOSURE STANDARD
Radiation Exposure Standards Used by Other Agencies
The Basis for NASA’s Current Space Radiation Exposure Standard
Committee’s Analysis of NASA’s Proposed Space Radiation Exposure Health Standard
4 COMMUNICATING ABOUT RADIATION-INDUCED CANCER RISKS
NASA’s Aims When Communicating Cancer Risk
Risk Communication Recipients and Their Needs
Considering NASA’s Proposed Risk Communication Tool for the Space Radiation Standard
Risk Communication and NASA’s Waiver Process
Risk Communication Research Opportunities for NASA
Acronyms and Abbreviations
|ALARA||as low as reasonably achievable|
|ARS||acute radiation syndrome|
|DDREF||dose and dose-rate effectiveness factor|
|EAR||excess absolute risk|
|ERR||excess relative risk|
|ESA||European Space Agency|
|GCR||galactic cosmic rays|
|HMTA||Health and Medical Technical Authority|
|ICRP||International Commission on Radiological Protection|
|ISS||International Space Station|
|JAXA||Japanese Space Agency|
|LD50||lethal dose to 50 percent of the human population|
|LDEF||low dose effect|
|LEO||low Earth orbit|
|LET||linear energy transfer|
|LSS||Life Span Study|
|NASA||National Aeronautics and Space Administration|
|NCRP||National Council on Radiation Protection and Measurements|
|NSCR||NASA Space Cancer Risk|
|OSHA||Occupational Safety and Health Administration|
|PMD||permissible mission duration|
|RADS||radiation-attributed decrease of survival|
|RBE||relative biological effectiveness|
|REIC||risk of exposure-induced cancer|
|REID||risk of exposure-induced death|
|RSA||Russian Space Agency|
|SPE||solar particle event|
|SPEL||space permissible exposure limit|