# Thermal Optimization Design for a Small Flat-Panel Synthetic Aperture Radar Satellite
## 6 Conclusions  
In this study, a thermal design strategy has been proposed for a high-resolution microwave remote sensing satellite, weighing 310 kg and orbiting in LEO. This strategy aims to achieve low weight, minimize energy consumption, and ensure high thermal stability. Utilizing a stacked antenna structure, an integrated structure-thermal design is employed for the antenna. This approach involves arranging active and passive thermal control elements within the structural gaps, along with the utilization of TIM to regulate the temperature levels of the antenna, thereby achieving a zero-power thermal design for the antenna. Simultaneously, it is imperative to maintain the temperature of the antenna support plate on the satellite platform at a constant 20 \({}^{\circ}\)C to minimize thermal deformation of the antenna. By adopting optimized design methods, we have successfully reduced the number of heaters required by 30%. Furthermore, by designing the temperature of the platform to hover around 20 \({}^{\circ}\)C, we have minimized the power consumption for thermal control of the support plate. A thermal simulation analysis was conducted on the satellite, revealing that the TCS can effectively ensure imaging in the typical 2 m stripmap mode for 100 s during each orbit cycle, even under extreme in-orbit conditions. Notably, all onboard components remain within the permissible temperature range, and the temperature variance among the core components of the antenna, specifically the T/RMs, remains minimal. The utilization of temperature-controlled microwave-absorbing devices guarantees the successful conduct of TVAC testing for high-power launches of the satellite. During the testing, the peak temperature of the T/RMs reached 28 \({}^{\circ}\)C, with a temperature variance not exceeding 3.6 \({}^{\circ}\)C, thus validating the efficacy of the thermal design strategy. The testing results also confirm that the thermal control design of the antenna indeed does not incur any energy consumption. This research approach will facilitate the simplification of thermal design for small SAR satellites and communication satellites with comparable configurations.  
Conceptualization, T.B., L.K. and Y.Z.; methodology, T.B. and Y.Z.; software, Y.Z.; validation, T.B., Y.Z. and J.Y.; formal analysis, T.B. and Y.Z.; data curation, T.B. and Y.Z.; writing--original draft preparation, T.B. and Y.Z.; writing--review and editing, T.B., L.K. and H.A.; supervision, L.K., L.Z. and H.A.; project administration, L.K. and H.A.; funding acquisition, J.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Jilin Province Science and Technology Development Plan Project of China, grant number 20230508156 RC.  
Data availability Statement: Data are available on request from the authors.  
Authors [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] were employed by the company Chang Guang Satellite Technology Co., Ltd. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.