Updating the Tools Used to Estimate Space Radiation Exposures for Operations: Codes, Models, and Interfaces 2002-01-2457

In order to estimate the exposure to a crew in space, there are three essential steps to be performed: first, the ambient radiation environment at the vehicle must be characterized; second, the mass distribution properties of the vehicle, including the crewmembers themselves must be developed, and third a model of the interactions of space radiations with matter must be employed in order to characterize the radiation field at the dose point of interest. The Space Radiation Analysis Group (SRAG) at the NASA, Johnson Space Center carries the primary responsibility for the operational radiation protection support function associated with manned space flight. In order to provide support during the various planning, execution, and analysis/recording phase activities associated with a given mission, tools have been developed to allow rapid, repeatable calculations of exposure on orbit. The majority of these tools implicitly contain numerical approximations, or other limitations included as a result of either hardware limitations (i.e. processor clock speed, RAM, etc.) present at the time of inception and initial development, or of limitations in scope inherent in the programming language(s) and version(s) of the time. Over the last ten years, prevalent desktop/daily use hardware has increased in speed by approximately three orders of magnitude, and there has been a concurrent improvement in the capacity, scope, and interoperability of programming languages. These improvements in available technology make possible updates to the tools used in exposure evaluation. Obviously, one expects an increase in speed purely as a result of executing existing algorithms on faster hardware. Beyond this, however, removal of some system constraints allows for a re-design of the tool suite in such a way as to provide for greater flexibility, an expanded scope of calculation, the addition of Graphical User Interfaces (GUIs), improved calculation stability and precision, and an additional increase in speed due to “in-lining” calculations and reconstructing of the algorithms in a manner which calls for fewer elemental calculations, as well as time saved through better interfaces with geometry models and code input routines. The overall result is to enhance the radiation protection capabilities available for manned space flight.