This paper describes an integrated thermal-mechanical architecture for responsive small satellites that combines the intrinsic thermal management capabilities of the Satellite Modular and Reconfigurable Thermal System (SMARTS) with the modular, quick assembly mechanical design offered by the Plug-and-Play Satellite-2 (PnPSat-2) structure. PnPSat-2 is the second generation Plug and Play satellite bus. SMARTS and PnPSat-2 are technology development programs funded by the Air Force Research Laboratory (AFRL) Space Vehicles Directorate at Kirtland AFB, NM. To meet the three-tiered responsive space needs of the DoD, varying levels of responsiveness from immediate (Tier 1), to days (Tier 2), to months (Tier 3) are needed. SMARTS offers an intrinsic thermal solution that combines a multi-heat pipe isothermal bus, oversized body-mounted radiators, a bus-to-radiator loop heat pipe (LHP) thermal transport/switching system, and maximum external insulation. PnPSat-2 offers an intrinsic mechanical solution that includes panels with embedded electronics, multiple component mounting locations, and features that allow the spacecraft to be transitioned to a flat-sat for easy assembly, integration, de-integration, and reassembly. To combine the two architectures, internal half-panels were redesigned to include spreader heat pipes (SHPs) for intra-panel isothermalization, side-to-top panel structural brackets were replaced by a combined bracket-header heat pipe (HHP) for inter-panel isothermalization, and an LHP evaporator was mounted to the HHP to enable variable conductance between the isothermal spacecraft bus and body-mounted (condensers) radiators. To evaluate the concept, a three-panel thermal test bed will be configured to simulate the combined SMARTS/PnPSat-2 configuration. The paper will describe the system design, key analytical trades, hardware status, and available test data.
