Last Published:  11/23/20 11:55:10 AM (Central)
Responsible Element: Space Radiation (SR)
Status: Closed
Closure Rationale
Domain transferred to NASA's Advanced Exploration Systems - Space Radiation Analysis Group.
Closure Documentation:
No Closure Documentation Available

Initial State of Gap:

The ability to determine optimal shielding configurations depends on the ability to evaluate the detrimental effects of radiation exposure and balance that with the cost of adding additional shielding and/or the impact of reconfiguring vehicle systems.  Selection of shielding materials and thickness must also consider the type and quantity of secondary radiations produced by the shielding and considering the LET and Z’s of the particles that ultimately reach the target.  Such an optimization process must support the requirement of “As Low as Reasonably Achievable (ALARA, NASA Standard 3001, Vol. 1)” with a cost benefit analysis; however, current assessments are limited by the uncertainties involved in the evaluation.  Other SRPE gaps cover the effort to reduce the biological and physical uncertainties associated with the evaluation of the radiation exposure and how the radiation is modified as it passes though material. This gap addresses specific issues associated with development of shielding optimization methodologies to accurately evaluate radiation protection strategies while accounting for the inherent multiple uncertainties associated with the problem. For most shield design efforts, effective dose for specific GCR or SPE radiation design environments has been calculated in order to determine the effectiveness of different shielding configurations to meet specific vehicle radiation requirements. However, additional methodologies incorporating probabilistic models are needed to reduce uncertainty in optimization calculations to properly assess the cost (mass savings) vs. benefit of further reducing exposures as required by ALARA. Such integrated optimization methodologies for ALARA do not currently exist.


Research to support the development of models and methodologies that include the probabilities associated with the natural variation in the radiation environment combined with the biological and physical uncertainties associated with risk calculations. SPE are sporadic events, and GCR intensity varies over time. In order to perform risk leveling, the probabilities associated with the variation in environments over time need to be accounted for in uncertainty assessments. Optimization algorithms and strategies using fully probabilistic calculations will be developed to support analysis of ALARA requirements. Ultimately, methodologies will be implemented within a systems, mission and architecture framework to enable quantification of cost versus benefit. Collaborations with NASA mission architecture teams is essential.

Target for Closure
  • Development of probabilistic SPE and GCR environmental models.

  • Methods to accurately quantify the cost versus benefit of shield mitigation strategies across biological and physical solutions for mission implementation.

  • Integration of methods into a collaborative analysis and design framework (Cancer 13).

  • Mission specific shielding recommendations for Exploration Architectures.

Risk Risk of Radiation Carcinogenesis
You are here! Gap Cancer 11: What are the most effective shielding approaches to mitigate cancer risks?

No Documentation Available