Speakers
Description
Advanced Data Handling Architecture (ADHA) standard [1] (under development by ESA with industrial partners) is a standard for the on-board computers and data handling systems to assure interoperability and cost efficiency. It utilizes standardized plug-in electronic modules interconnected in larger enclosures called electronic boxes. A similar philosophy was adopted to an older standard called SpaceVPX (Vita 78). However, with rising power demands for on-board spacecraft processing of data, comes increased thermal dissipation which limits the possible performance of the ADHA and SpaceVPX based modules. Simulations and experiments performed by KP Labs showed the importance of proper thermal design of such modules. In some scenarios, temperatures of electronics can rise above 75°C, which is undesirable for a reliability of electronic components [2]. Additionally, the periodic operation of the module’s electronics creates thermal cycles that significantly reduce the component’s lifetime [3]. To address these issues, the authors proposed the utilization of a novel 3D printed mechanical enclosure with embedded Phase Change Material (PCM), applied on a module level. The goal of this solution is to store energy in the form of latent heat during high power dissipation phases and release it during non-operational phases. This in turn would reduce temperature fluctuations and prevent overheating of electronics, thus enhancing their reliability.
The core novelty of the authors’ approach lies in the design and development of a PCM based Data Processing Unit (DPU) module to the ADHA and SpaceVPX standards, marking the first known integration of a PCM system with these standards. This extends the authors' previous work, which tested only the module enclosure with embedded PCM. In current work, for the first time, electronics are used with PCM enclosure in the form of the Engineering Model of Lion DPU developed by KP Labs for SpaceVPX standard.
The authors conducted numerical simulations of the new DPU with a PCM-based enclosure. The detailed numerical FEA model was used to analyze the processes within the DPU module in detail. It allowed for an in-depth study of the entire concept, including the influence of gravity vector on the heat transfer. However, to speed up the future development, the complex FEA model was simplified to a nodal model in ESATAN TMS. Such simplification will also allow for easier exchange of thermal models with Large System Integrators (LSI). In ESATAN, the DPU’s geometry was represented as a network of 1D nodes with representative heat capacitances and power dissipations, connected by one-dimensional conductive links. The PCM was modeled as a node with temperature-dependent heat capacity. This approach reduced computational power and shortened calculation times, a significant benefit for the engineering community designing space electronics.
A physical DPU prototype was manufactured and tested inside a Thermal Vacuum Chamber (TVAC). Paraffin n-eicosane, with a melting temperature of 37°C and a latent heat of 247 kJ/g [3], was used as the PCM. To address the challenge of low thermal conductivity of the selected paraffin, the aluminum PCM container was created with additive manufacturing technology. This approach allowed for the creation of a hollow mechanical enclosure with 3D printed fins, while keeping the mechanical requirements of SpaceVPX standard.
The experimental procedure consisted of a Thermal Balance Test (TBT) and a Thermal Cycling Test (TCT). During the TBT, phase change occurred, slowing the temperature rise of the Lion’s electronics, which experimentally confirmed the PCM's positive impact on the DPU's thermal design. Following these real-life results, the simulations (both the detailed and simplified) were validated and compared. During the TCT, the PCM stabilized the temperature variation of the electronic components. The obtained results and correlation between numerical simulations and TVAC tests will be presented in detail during the author’s presentation.
The simulations and subsequent TVAC tests of Lion DPU EM proved the concept of the PCM-based module for SpaceVPX in real operational scenarios. By utilizing a phase change, temperature spans can be significantly reduced with relatively low additional mass added to the DPU. This solution offers benefits in terms of extending the operational lifetime of the electronic components. The authors are currently working on the possible extension of this approach to the ADHA standard, to meet future demand of the growing on-board data handling solutions market.
References:
[1] Advanced data handling architecture - adha, accessed: 2024-03-24. URL https://technology.esa.int/page/advanced-data-handling-architecture-adha
[2] S.M. Sohel Murshed, C.A. Nieto de Castro, “A critical review of traditional and emerging techniques and fluids for electronics cooling”, 2017
[3] Sharon, Gil & Caswell, Greg. . Temperature cycling and fatigue in electronics. Advancing Microelectronics. 42. 18-24. (2015)
[4] Serale et al. Potentialities of a Low Temperature Solar Heating System Based on Slurry Phase Change Materials (PCS). Energy Procedia. 10.1016/j.egypro.2014.12.397. (2014).
