Plastic, the impenetrable shield?
Research, recently conducted, at the University of New Hampshire (UNH) and the Southwest Research Institute (SwRI) indicates that plastic could provide effective shielding against radiation hazards faced by astronauts during space travel. This is not the first time that this property has been mentioned, but this study is the first to confirm it thanks to data gathered in space.
The scientists reached their findings using data gathered by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) which has been in orbit around the Moon since 2009. Specifically, the instrument gauged the radiation dose of cosmic rays after passing through a material known as "tissue-equivalent plastic", which simulated human muscle tissue. The data was then validated against ground-based measurements taken during previous studies. These studies aimed to test various materials by simulating radiation using beams of heavy particles. This enabled scientists to compare the effectiveness of plastic (namely of polyethylene) to that of aluminium. The different results obtained in ground-based and space-based tests helped to confirm the plastic's filtering power. "The shielding effectiveness of the plastic in space is very much in line with what we discovered from the beam experiments, so we've gained a lot of confidence in the conclusions we drew from that work", said Cary Zeitlin of the SwRI Earth, Oceans, and Space Department. NASA had previously developed RXF1, a polyethylene-based material used as shielding for the sensitive parts of spacecraft.
This discovery could provide a solution to the problem of radiation which, even today, is still a considerable obstacle for long-haul space travel. However, although the material blocks out many types of radiation, the strongest of those might still manage to penetrate the material. The research must go on, particularly in light of the fact that the limit of the dose of cosmic radiation the body can endure is still unknown.
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