NASA funded: The project has identified two PCM HX concepts that have paths for possible infusion to future vehicles such as Orion. The project includes development and an eventual technology demonstration on the International Space Station (ISS). The first heat exchanger is wax-based and has reached a TRL of 4. The project will build a wax-based PCM HX in partnership with UTC Aerospace for flight demonstration on ISS. Testing a wax-based PCM HX in a relevant environment will allow an "off the shelf" option for future vehicles, such as Orion, that require long duration supplemental heat rejection.