Two-phase spacecraft equipment cooling loops offer significant improvements in performance as compared to conventional single-phase loops. However, work must be done in the design of two-phase loop components to assure zero-g compatible operation and one-g test verification.This paper presents the development* of a key two-phase component: the evaporative cold plate. A high-performance subscale section was designed, built, and tested. The prototype design allowed interchangeable components so the combination that maximized the performance could be found. The resulting plate showed good heat transfer performance, fast start-up, insensitivity to vapor or gases at the inlet, and fast recovery from dryout.