Abstract: The phase-change accommodating rigid fluid container disclosed herein includes a variety of features that protect the container from phase changes of a fluid stored therein. As a result, the container may be in direct contact with the fluid without any flexible membrane or bag there between. For example, the fluid container may include one or more of matched pairs of recesses for physical manipulation of the container, stiffening ribs extending between the recesses, and input/output assemblies acting as inputs for fluid into the container, outputs of fluid from the container, and vents for pressure equalization of the container.