Analyses of Hubble Space Telescope Aluminized-Teflon Insulation Retrieved After 19 Years of Space Exposure

Electron Irradiation Effects on Strength and Ductility of Polymer Foils Studied by Femtosecond Laser-Processed Micro-Tensile Specimens

“…The electron irradiation doses of the outer layer of thermal blankets of the Hubble Space Telescope in the low Earth orbit roughly range from 100 kGy to about 1 MGy for the shortest servicing missions up to the defined end-of-life duration respectively [2,24]. The electron irradiation doses investigated in this study cover this dose range.…”

Small-scale mechanical characterization of space-exposed fluorinated ethylene propylene recovered from the Hubble Space Telescope

“…The exposure levels, based on equivalent solar hours, were estimated to be 24,300 hours for region 1 of Bay 5, 30,300 hours for the patched region (region 11) of Bay 8, and 89,300 hours for the un-patched region (region 1) of Bay 8 [4] . These equivalent solar hour estimates were determined by accounting for the time in orbit, the percent of time the material was shielded by the earth, and a region's nominal angle with respect to the sun.…”

“…In terms of thermal fluctuations, both bays and all regions underwent 110,000 cycles with temperatures estimated to range from -175°C to 0°C for Bay 5 and between -175°C to 40°C for Bay 8 [4] . The as-fabricated material consisting of the FEP film [14] with a thin layer of vapor deposited Al had a nominal thickness of 127μm; however, prolonged exposure to space resulted in cracking of FEP as well as cracking and partial delamination of the Al coating.…”

“…These Al-FEP blankets had been in low earth orbit since Hubble's deployment, with regions varying in exposure to solar radiation, thermal cycling, space debris, and atomic oxygen. Previous NASA studies [1][2][3] [4] were performed to understand the combined effect of temperature cycling and solar radiation on the Al-FEP.…”

“…Ultraviolet and x-ray radiation from the sun as well as a strong flux of protons and 3 electrons from the lower Van Allen belt penetrate the Al-FEP and react with the polymer. Other NASA researchers have made estimates regarding the fluence of x-rays, protons, and electrons [4] , though it remains challenging to isolate and quantify the specific contribution each factor has on the Al-FEP. In general, depending on the temperature conditions, these radiation events can cause either chain scission and/or chain cross-linking [6] [7] .…”