Characterization of an Ice Adhesion Reduction Coating for the Space Shuttle Liquid Hydrogen and Liquid Oxygen Umbilical Systems

Abstract NASA has recently developed an ice adhesion reduction coating given the designation Shuttle Ice Liberation Coating (SILC). SILC provides reduced adhesion of ice to a variety of substrate materials commonly found on the Space Shuttle External Tank (ET) and Orbiter. ET thermal protection system (TPS) material substrates, Stepanfoam BX-265, North Carolina Foam Industries (NCFI) 24-124, and Polymer Development Laboratory (PDL)-1034, were tested in tensile mode to evaluate ice adhesion. Tensile testing of ice grown onto these substrates was conducted at −18°C (0°F) and −7°C (20°F). For all tests the ice adhesion to the sample was reduced by approximately 90% for test samples coated with SILC compared with uncoated test samples. The durability of the SILC material was demonstrated by consistently good performance after multiple test cycles. SILC durability was verified by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive Spectroscopy (EDS) and contact angle goniometry experiments on pristine, mechanically tested and weathered and aged samples. SILC development, mechanical testing, and testing of flight hardware for ice adhesion on Space Shuttle hardware in relevant atmospheric conditions demonstrated the ability of SILC to reduce and affect the formation of ice and its ability to adhere.