Thermal management for multifunctional structures

Multifunctional structures (MFS) are an innovative concept that offer a new methodology for spacecraft design, eliminating chassis, cables and connectors, and integrating the electronics into the walls of the spacecraft. The MFS design consists of multilayer flexible circuit patches bonded onto a structural composite panel, and multichip modules (MCMs) performing specific functions are bonded onto the circuit patches which are interconnected via flexible circuit jumpers. Incorporation of the high power density two-dimensional (2-D) and three-dimensional (3-D) MCM's into smaller and more efficient packaging designs still has the fundamental requirement to maintain component temperatures within design limits. Higher component qualification temperatures, such as 393 K, can result in smaller spacecraft radiator areas that are consistent with efficient packaging schemes. During the MFS development effort, a structural radiator panel was fabricated using high thermal conductivity (Hi-K) composite facesheets, and several thermal management designs using combinations of Hi-K doublers (150-1500 W/m-K), Hi-K (150-700 W/m-K) corefill, and deployable radiators to maximize MCM's heat rejection. Results of the thermal vacuum tests and details of the thermal design methodology are presented in this paper.