Abstract: A twist capsule rotary joint system for passing a fluid through a pressure hull without a dynamic seal. A rotating cylindrical drum positioned outboard of the pressure hull is adapted to be driven in a reciprocating manner through an angle and backward through the same angle. At least one outboard pressure line or hose has a first end attached to a fixed connector that extends through the pressure hull near and radially outward of the rotating cylindrical drum. A second end of the outboard pressure line or hose is attached to a connector that extends through the top outboard surface of the drum. As the drum rotates, the pressure line wraps around the drum, or unwraps from the drum. In an exemplary embodiment, two pressure lines carry two-phase coolant through the pressure hull of a spacecraft in support of a rotating radiator that is adapted to rotate to present a minimum surface area toward the sun.