Abstract: A check valve is disclosed that includes a base having a porous first surface, a keeper coupled to the base, and a flexible leaf with a first section that is fixedly coupled between the keeper and the base and a second section that is cantilevered from the first section. The leaf has a first position when the leaf is fully in contact with the base and a second position when the leaf is fully in contact with the keeper. The leaf is configured to sealingly cover the porous first surface when the leaf is in the first position. The leaf is in an unstressed configuration when in the first position, and a maximum stress in the leaf is less than the yield stress when the leaf is in the second position. The check valve is particularly suited for use with cryogenic fluids such as liquid hydrogen and liquid oxygen.