Future NASA space missions require advanced systems to convert thermal energy into electric power. These systems must be reliable, efficient, and lightweight. In response, we propose to develop a turbo-Brayton power converter with high efficiency and specific power. The converter will use gas bearings to provide reliable, maintenance-free, long-life operation. It will also consist of discrete components that can be packaged to fit optimally with other subsystems, and its continuous gas flow can communicate directly with remote heat sources and heat rejection surfaces without ancillary heat transfer components and intermediate flow loops. Creare is well suited to succeed because we have a long history of developing advanced turbomachines, heat exchangers, and Brayton systems for challenging spaceflight applications. We will complete detailed analyses, trade studies, fabrication trials, and preliminary designs for the components and converter assembly during Phase I, followed by fabrication and testing of a breadboard converter during Phase II.