RadWorks Storm Shelter Design for Solar Particle Event Shielding

Abstract

In order to enable long-duration human exploration beyond low-Earth orbit, the risks associated with exposure of astronaut crews to space radiation must be mitigated with practical and affordable solutions. The space radiation environment beyond the magnetosphere is primarily a combination of two types of radiation: galactic cosmic rays (GCR) and solar particle events (SPE). While mitigating GCR exposure remains an open issue, reducing astronaut exposure to SPEs is achievable through material shielding because they are made up primarily of medium-energy protons. In order to ensure astronaut safety for long durations beyond low-Earth orbit, SPE radiation exposure must be mitigated. However, the increasingly demanding spacecraft propulsive performance for these ambitious missions requires minimal mass and volume radiation shielding solutions which leverage available multi-functional habitat structures and logistics as much as possible. This paper describes the efforts of NASA's RadWorks Advanced Exploration Systems (AES) Project to design minimal mass SPE radiation shelter concepts leveraging available resources. Discussion items include a description of the shelter trade space, the prioritization process used to identify the four primary shelter concepts chosen for maturation, a summary of each concept's design features, a description of the radiation analysis process, and an assessment of the parasitic mass of each concept. Nomenclature AcronymsAES = Advanced Exploration Systems BEO = Beyond Earth Orbit BNNT = Boron Nitride Nanotubes CAD = Computer-Aided Design CQ = Crew Quarter CTB = Cargo Transfer Bag DSH = Deep Space Habitat FAX = Female Adult voXel GCR = Galactic Cosmic Ray HAT = Human Spaceflight Architecture Team HDU = Habitat Demonstration Unit HMC = Heat Melt Compactor HZETRN = High charge (Z) and Energy TRaNsport code ISS = International Space Station KPP = Key Performance Parameter LEO = Low Earth Orbit OLTARIS = On-Line Tool for the Assessment of Radiation in Space SPE = Solar Particle Event

Limitations in predicting radiation-induced pharmaceutical instability during long-duration spaceflight

“…56 In collaborative efforts to protect human crew from radiation exposure, there has been much discussion regarding the inclusion of a heavily-shielded compartment of thick aluminum or other radioprotective material, or alternatively by the use of "multi-purpose shielding solutions," such as barriers composed of water or food supplies, on exploration vehicles. 56,59,60 Pharmaceuticals could be stored within a shielded compartment to reduce radiation exposures. While these innovative efforts show promise, it is important to remember that shielding designs may be limited by mass and volume constraints and lift-mass capabilities of the launching vehicle.…”

Design of Two RadWorks Storm Shelters for Solar Particle Event Shielding

“…This section describes the process used, which is very similar to the process used in the previous year's analysis 1,6 , but now utilizes new probabilistic analysis to model the SPE spectra.…”

<strong>Pharmaceutical Solutions for Deep Space Travel and Colonization: Background, Challenges, and Possibilities</strong>

“…Regarding in-flight storage, both pre-established and deployable, "just-in-time" barriers have been proposed as potential radiation shielding solutions [40]. Such structures, by reducing crew exposure to radiation, will mitigate DNA damage, cancer, other health risks [15][44] [59], and the use of more medications to treat these conditions. Simultaneously, pharmaceuticals stored in or moved to these protected areas will be subject to reduced exposure as well [55] [40].…”