Speakers
Description
Adjustable Support Structure for Optical Sensors, ASSOSS - Thermal System
ASSOSS is a novel structure designed to provide structural support and efficient thermal management for optical space sensors, developed in a joint venture between Space Structures GmbH, BTU Cottbus-Senftenberg, and Fraunhofer IAP. This innovative project focuses on integrating ultra-lightweight materials, modularity in terms of height adjustment, number of sensors, and thermal strap design, along with high dimensional stability. The primary mechanical structure, research on efficient CFRP to CFRP joining technologies, and the development of a new lightweight thermal strap to transport heat from the optical sensor to the radiator were key development points. An outline of the design, manufacture, and testing of thermal strap and the system level thermal tests of ASSOSS will be presented in ESTEW 2024.
The thermal system of the ASSOSS focuses mainly on the thermal strap – radiator combination for effective heat transfer. The thermal strap was developed as a lightweight alternative to traditional copper-based systems to enhance thermal conductance while reducing mass in space applications. The development was done at BTU, Cottbus as a part of research activities. The developmental process included four key stages: material selection, thermal design, manufacturing, and testing. Graphite was selected for its excellent thermal conductivity and lightweight properties. During the design phase, the strap's configuration was optimized using hand calculations and finite element analysis to meet the ASSOSS project's geometric constraints and thermal requirements. Manufacturing faced challenges in bonding the delicate graphite foils, which were overcome by developing specialized techniques. A custom test rig measured the strap's thermal conductance in a vacuum chamber, confirming its effectiveness in managing thermal loads and validating the design phase results.
At the system level, the ASSOSS assembly is subjected to thermal simulations for radiator sizing and to analyze the performance of the system in orbit at different phases of the project. The initial analyses were done based on assumptions and later the data from the heat strap was included to simulate the unit more accurately. After successful tests of the thermal strap, it is then integrated into the ASSOSS system at Space Structures GmbH, Berlin. The complete system is subjected to thermal ambient cycling, thermal balance test and thermal vacuum cycling tests.
