&lt;p&gt;Project has identified two PCM HX concepts that will be designed, developed and demonstrated on-board the International Space Station (ISS):&lt;/p&gt;&lt;ul&gt;&lt;li&gt;The first heat exchanger is wax-based, is currently at TRL4. The heat exchanger utilizes paraffin wax to aid in the process of supplying a vehicle a sources of supplemental heat rejection when needed. NASA Johnson Space Center has partnered with UTC Aerospace via a NASA NRA.&lt;/li&gt;&lt;li&gt;The second heat exchanger is a water-based Phase Change Material Heat Exchanger and is currently at a TRL of 3. Johnson Space Center has partnered with Mezzo Technologies to develop the next generation of light weight water based PCM HXs.&lt;ul style="list-style-type:circle"&gt;&lt;li&gt;Leveraging a Phase III Maturation SBIR in partnership with Mezzo Technologies to evaluate multiple water-based PCM HX concepts.&lt;/li&gt;&lt;/ul&gt;&lt;/li&gt;&lt;/ul&gt;&lt;p&gt;Initial phase of development includes the development and fabrication of wax PCM HX with UTAS for flight demonstration on the International Space Station. The ISS Program is supporting the project by providing resources to build and certify for flight a platform that can aid in demonstrating these PCM HXs on the ISS. In parallel to this effort, the project will work with Mezzo Technologies to advance the TRL of the water based PCM HX. Water is known to have the double latent energy storage of wax based PCMs. With this increase in energy storage, by using water as a PCM, the project can leverage possible mass and volume savings. If determined viable, the project will transition the development into the fabrication of a flight water PCM HX for demonstration on the same ISS research platform. Through testing these heat exchangers in an environment that only the International Space Station can provide, NASA will help advance PCM HX technology for future exploration and commercial crew vehicles. Currently, Orion has baselined the use of PCM HXs in its Exploration Mission 2 architecture.&amp;nbsp;&lt;/p&gt;