Gap Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement? (Closed. Transferred to Operations)
Last Published:  07/30/21 01:05:31 PM (Central)
Responsible Element: Space Radiation (SR)
Status: Closed
Closure Rationale

Technologies for space radiation shielding are very well understood and, unlike GCR exposures, it is established that it is possible to effectively shield against radiation exposures from solar particle events, with polyethylene or water as optimal shielding materials. A recent review by the National Research Council (NRC, 2012) states, “The Committee considers that the radiation environment and shielding transport models used in the NASA’s proposed model are a major step forward compared to previous models used. This is especially the case for the statistical solar particle event model. The current models have been developed by making extensive use of the available data and rigourous mathematical analysis The uncertainties conservatively allocated to the space physics parameters are deemed to be adequate at this time, considering that the space physics uncertainties is only a minor contributor to the overall cancer risk assessment. Although further research in this area could reduce the uncertainty, the law of diminishing returns may prevail.”  This is borne out by flight experiments comparing the HZETRN/QMSFRG model to dosimetry and spectrometry data (Cucinotta et al., 2008; Badhwar and Cucinotta, 1998; 2000) and accelerator experiments with various shielding materials (George and Cucinotta, 2007; Durante et al., 2005).


Shielding optimization analysis is required during mission design to reduce mass and ensure other material requirements for spacecraft structures are satisfied. Aluminum shielding is shown to reduce SPE risks to small doses (<100 mSv) for all recorded SPE’s, however shielding mass reductions can be found using polyethylene, water or other hydrogenous materials. Accurate estimation of organ dose, models of the space radiation environment, and tools for optimization of shielding for specific mission design have been developed. The ARRBOD model combines the Acute Radiation Risk (ARR) code and NASA Baryon Transport code (BRYNTRN) in a user friendly GUI that can be used to calculate organ doses and risk of crew/mission impairment due to acute radiation exposure and EVA mission timelines; and OLTARIS (The On-Line Tool for the Assessment of Radiation in Space is a web-based set of tools and models for assessing the effects of space radiation on spacecraft, habitats, rovers, and spacesuits and is useful for shelter design/ configuration including specification of any material.  A full description of the technologies for shielding analysis for acute radiation exposures can be found in the references listed below.






National Research Council, Technical Evaluation of the NASA Model for Cancer Risk to Astronauts due to Space Radiation. NRC, 2012.


Badhwar, G. D. and Cucinotta, F.A.:  Depth Dependence of Absorbed Dose, Dose Equivalent, and LET in Polyethylene and Comparison With Model Calculations.  Radiation Research 149, 209-218, 1998.


Badhwar, G.D., and Cucinotta, F.A. A Comparison on Depth Dependence of Dose and Linear Energy Transfer Spectra in Aluminum and Polyethylene.  Radiation Research 153, 1-8, 2000.


Kim, M.Y., Hayat, M. J., Feiveson A. H., and Cucinotta, F.A. Prediction of Frequency And Exposure Level Of Solar Particle Events. Health Physics  97, 68-81, 2009.


Kim, MY, Hu X, Cucinotta, FA. Effect of shielding materials from SPEs on the lunar and Mars surface. Reston, VA: American Institute of Aeronautics and Astronautics; paper number AIAA 2005-6653; 2005.


Myung-HeeY. Kim, Francis A. Cucinotta, John W. Wilson.  Mean occurrence frequency and temporal risk analysis of solar particle events. Radiation Measurements 41, 2006. 1115– 1122.


Myung-Hee Y. Kim and Francis A. Cucinotta. PROBABILISTIC ASSESSMENT OF RADIATION RISK FOR SOLAR PARTICLE EVENTS Proc. of ‘3rd IAASS Conference – Building a Safer Space Together’, Rome, Italy 21–23 October 2008, (ESA SP-662, January 2009)


Myung-Hee Y. Kim, Shaowen Hu, Hatem N. Nounu, and Francis A. Cucinotta. Development of Graphical User Interface for ARRBOD (Acute Radiation Risk and BRYNTRN Organ Dose Projection) NASA/TP-2010-216116. February 2010.


R. Singleterry, S. Blattnig, M. Clowdsley, G. Qualls, C. Sandridge, L. Simonsen, J. Norbury, T. Slaba, S. Walker, F. Badavi, J. Spangler, A. Aumann, E. Zapp, R. Rutledge, K. Lee, and R. Norman. OLTARIS: On-Line Tool for the Assessment of Radiation in Space. NASA/TP-2010-216722. July 2010. 


Cucinotta F.A., Kim M.H., Willingham V., George K.A. Physical and biological organ dosimetry analysis for International Space Station Astronauts. Radiation Research 170, 127–138, 2008.


F.A Cucinotta, M.-H.Y. Kim, and L.J. Chappell. Evaluating Shielding Approaches to Reduce Space Radiation Cancer Risks. NASA TM-2012-217361 May 2012.


Durante, M., George, K., Grossi, J.F., Miller, J., and Cucinotta, F.A.: Cytogenetic Effects of High-energy Iron Ions: Dependence on Shielding Thickness and Material. Radiation Research 164, 571-576, 2005.

George, K., and Cucinotta, F.A. The influence of shielding on the biological effectiveness of accelerated particles for the induction of chromosome damage. Advances in Space Research, 39(6), 1076-1081, 2007.

Closure Documentation:
No Closure Documentation Available

1. Present state:
Closed. Transferred to Operations. Future work in this area will be performed by them.

2. Target for Closure: 

NASA has invested in shielding technologies for many years and understanding is nearly complete. Solar events can be shielded: HZETRN/BRYNTRN, NSRL-AGS experiments show polyethylene or water shielding are optimal materials. (Note, this is distinct from galactic cosmic ray exposure, which would require enormous mass to shield because of high energies and secondary radiation). ARRBOD model allows calculation of gender specific whole body effective dose for astronauts inside spacecraft, with specified shielding thickness, coupled with and probabilistic assessment of risk of acute radiation effects. ARRBOD and OLTARIS will be used for shielding assessments for future mission design as required.

3. Interim Stages (Metrics):

  • Lunar Architecture Shielding Assessments – completed.
  • Constellation Architecture Studies – completed.
  • Future Exploration Architecture Studies -as required.

 4. Approach:


1)      Integrated Radiation Analysis and Design Tool Delivery Milestone: 3/31/2012  (Sandridge,  Direct)

2)      Patterns of Energy Deposition by HZE Particles in Cellular Targets Delivery Milestone: 10/30/2011 (Dingfelder SR NRA)

3)      Space Radiation Risk Assessment Project: Perform a comprehensive assessment of available acute radiation risk projection models, and t develop simulation software of acute risk for mission design assessments. Mission and Vehicle radiation analyses, as required


Delivery Milestones:

ESAS shielding analysis results to mission planners (2006)             

Lunar Architecture Shielding Assessments.    (2007)

Design Tool Inputs Received       (2007, 2008)

Acute Radiation Risk Body Organ Doses (ARRBOD) (9/2009)

Constellation Architecture Studies CAT (Data Analysis) (2010)

End-to-end mission radiation analysis     (2010)

Design Tool Inputs (2012)

ARRBOD model updates (2013, 2016)

Target for Closure
No Target for Closure available.
You are here! Gap Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement? (Closed. Transferred to Operations)

Multi-Disciplinary Research Plans

No Documentation Available