The control of temperature and humidity in spacecraft cabins is a vital component of environmental-control and life-support systems. Separating the two phases (i.e., water and air) that result from cooling air for humidity control represents a major technical challenge in the microgravity environment of space.With NASA funding, Bend Research has developed a membrane-based condensate-recovery heat exchanger (CRX) to address this challenge. The CRX offers substantial advantages in simplicity, reliability, mass, and volume over competing technologies. The high heat transfer and mass transfer in this device promise to provide superior humidity control without the need for complex mechanical separators. Moreover, these high transfer rates are achieved with minimal pressure drop, reducing power requirements.In this paper, we review previous work to develop a mathematical model of the CRX and compare the performance of CRX modules during testing with the performance predicted by the model, as well as with the performance of conventional temperature- and humidity-control devices.