A wide range of environmental exposures, stringent payload interface conditions, a low risk requirement, low allowable heater power, constraints of a fixed price contract and aggressive schedule presented a challenge in developing the FUSE bus (spacecraft) thermal design. The bus provides power, attitude control and telemetry for the satellite, which includes the bus and instrument payload. The thermal design that evolved is remarkably self-regulating. This is attributed to the synergistic effect of a compact structure that allows cross-coupling of radiators with different exposures in addition to the advantages of a large louver. This paper discusses the design approach, key thermal control features, supporting analyses and trade studies, and how predicted results compare with requirements for the design envelope and beyond.