An optimal shielding configuration has been realized during a phase I NASA NIACstudy, and it is referred to as a Magnetospheric Dipolar Torus (MDT).>A This configuration has the singular ability to deflect the vast majority of the GCR including HZE ions. In addition, the MDT shields both habitat and magnets eliminating the secondary particle irradiation hazard, which can dominate over the primary GCR for the closed magnetic topologies that have been investigated in the past. MDT shielding also reduces structural, mass and power requirements. For phase II a low cost method for testing shielding on Earth had been devised using cosmic GeV muons as a surrogate for the GCR encountered in space.
Above – Graphic depiction of Spacecraft Scale Magnetospheric Protection from Galactic Cosmic Radiation Credits: J. Slough
During the phase I study MSNW developed 3-D relativistic particle code to evaluate magnetic shielding of GCR and evaluated a wide range of magnetic topologies and shielding approaches from nested tori to large, plasma- based magnetospheric configurations. It was found that by far the best shielding performance was obtained for the MDT configuration. The plans for phase II include an upgrade of the MSNW particle code to include material activation and a full range of GCR ions and energies. The improved particle code will be employed to characterize and optimize a subscale MDT for shielding GCR-generated muons arriving at the Earth’s surface. The subscale MDT will be designed, built, and then perform several shielding tests using the GCR induced muons at various locations and elevations. The intent is to the validate MDT concept and bring it to TRL 4. A detailed design will be carried out for the next stage of development employing High Temperature Superconducting Coils and plans for both structures and space habitat. A substantial effort will be made to find critical NASA and commercial aerospace partners for future testing in Phase III to TRL 5.