A radiation vest beat a same-mass full-body shield, in a model
Published
What DLR reports: on Artemis I in 2022, two torso phantoms, each built from 38 tissue-equivalent plastic discs, flew with dosimeters. One wore the StemRad AstroRad vest and one did not. No significant solar storm occurred, so the team extrapolated the measured Van Allen belt data to past storms. The extrapolation indicates the vest would cut effective dose by about 60% for an August 1972-type event and just under 40% for an October 1989-type event, and in the model a full-body shield of the same mass gave roughly 30% less protection than the targeted vest. The flown vest weighed about 26 kg. The paper is in Science Advances. Why it matters for materials: hydrogen-rich polymers such as polyethylene tend to stop protons well per kilogram, so the design question is where the mass goes, not only which polymer is used. DLR says only that the vest core is a polymer with a high hydrogen content and does not name it. Our take: the storm figures are modelled, not measured in a storm, from two female torso phantoms on a single flight, and four of the paper's 21 listed authors have StemRad, the vest's developer, as their affiliation (Crossref record). DLR gives the vest mass (about 26 kg) and notes that mass and volume are generally limiting in spaceflight, but gives no target mass or launch-cost figure. As plain reference values for polyethylene, a common hydrogen-rich polymer, our HDPE page lists densities of 0.959 g/cm3 (SCG H5818J) and 0.955 g/cm3 (machining sheet), and our borated polyethylene page lists 1.04 g/cm3 for one 5 % boron grade (JCPE5) and 1.01 g/cc for another (MarShield). What we would watch: whether a real solar particle event gives the same ratio, and what the vest weighs after redesign. Would you fly the mass?