Spacecraft cold-plate designs are small, relatively complex, and expensive. A large-size, low-cost approach is required for the new generation of space power modules and platforms. This paper describes part of an on-going investigation of the feasibility of using large aluminum extrusions attached side-by-side to form a large, two-sided cold plate with integral coolant passages.The objective was to establish and verify a cold-plate-to-equipment interface design that would meet thermal performance requirements and allow easy replacement by extravehicular activity (EVA) component changeout. Approximately twelve filler materials and six interface designs were studied, and these were selected: three filler approaches, an existing adjustable interface pressure design, and a conventional design with no filler and no adjustment. Thermal conductance tests performed on simulated implementations of these approaches measured the contact conductances of each. Two designs met thermal as well as operational requirements.