Investigating the effect of ionizing particle radiation on the hypervelocity impact performance of UHMWPE-stuffed space debris shields

Abstract

Here the impact of environmental ionizing proton dose on the hypervelocity impact (HVI) performance of aluminium foam sandwich panels (AFSP) stuffed with the composite of Ultrahigh Molecular Weight Polyethylene (UHMWPE) Dyneema HB311 when serving as the outer wall of a satellite in sun-synchronous low earth orbit (LEO) is examined. A series of Dyneema samples are subjected to varying total ionizing doses by proton exposure calculated to be representative of that which might be imparted during representative LEO missions. The irradiated samples are then subject to quasi-static mechanical tensile tests and changes in ultimate tensile strength (UTS) are determined. The irradiated samples are examined using Attenuated Total Reflectance Fourier-Transformed Infrared (ATR-FTIR) Spectroscopy, from which a clear change in sample chemistry is identified. The measured changes in UTS are then fed into a pre-validated finite element numerical model to determine the effect on the protective capability Dyneema-stuffed AFSPs for space debris protection. The simulations yield a worst case reduction in performance of 11%, measured in terms of the critical diameter of a spherical aluminium projectile, d_c, impacting at 7 km/s. Over the range of ionizing doses imparted a weak dependence of d_c on applied dose is identified. Together, this analysis suggests the LEO radiation environment is not a significant factor in decreasing the impact protection performance of a Dyneema-stuffed AFSP over the lifetime of a typical LEO spacecraft mission.