Benefits of surface coatings for impacted composites for cryogenic tankage

NASA intends to use composite materials for both fuel tanks and fuel feedlines on future generations of reusable launch vehicles in an effort to reduce the overall vehicle weight, which in turn increases the weight of payload that can be sent into orbit. Composite feedlines have been found to be vulnerable to impacts (dropped tools and accidental bumps, etc.). Because composites dissipate impact energy through the formation of damage, it was necessary to determine whether polymeric coating materials could be used to improve the composite's resistance to impact, and also whether these same coatings could prevent fuel permeation through any damage that would result from these impacts. Furthermore, many polymeric materials continue to embrittle with time, and so the effects of aging were studied. Finally, thermal cycling of the coated composite specimens was performed to simulate the conditions present in launch-to-landing cycles.