Effect of Simulated Galactic Cosmic Ray (GCR) and Solar Particle Event (SPE) Radiation on Spectra® Restraint Fabric

Spectra®, 6 or a similar ultra-high-molecular-weight polyethylene (UHMWPE) fabric, is the likely choice for the restraint layer in future space suits due to its high strength-to-weight ratio, excellent abrasion and cut resistance, and excellent dimensional stability. During a Mars mission, space suits will be subjected to ionizing radiation during low Earth orbit (LEO), deep space transit to Mars, and the stay on the Martian surface. To ensure that space suit pressure garment materials do not experience unacceptable radiation-induced degradation during mission, it is important to characterize relevant mechanical and physical property changes after irradiation with particle radiation representative of the types of radiation encountered in the space radiation environment. In this paper, the puncture resistance was evaluated for several particle types (protons and iron), energies (30-MeV/amu protons, 1-GeV/amu protons and 1-GeV/amu iron), and doses (40 to 10,300 cGy). In most cases, little or no significant change in the puncture resistance of Spectra® was noted. The largest change observed was a 20.6% drop (for a layer close to the Bragg peak) in the initial puncture extension for Spectra® exposed to a 10,300-cGy proton Bragg peak dose. Similarly large drops in the initial puncture extension were also noted for Spectra® exposed to 400 to 709-cGy 1-GeV/amu iron irradiations. Relevance of the current results and recommendations for future testing are discussed.