The thermal analysis of stratospheric balloon payloads is still a complex task due to the variable thermal environment during the flight phases as well as due to the convective effects during the ascent. An experiment named HERCCULES has been successfully launched from Esrange Space Centre (Kiruna, Sweden) in September 2023 as part of the REXUS/BEXUS programme. This experiment aimed of serving as a heat transfer and thermal environment characterization platform that allow to validate previously developed methodologies for the worst-case thermal environmental conditions’ selection and the thermal analysis of these platforms. The experiment has been developed in an academic environment and the design, manufacturing, integration and test activities were mainly performed by Bachelor, Master and Ph.D. students with the mentorship of the European Space Agency. A low-cost design was achieved by using Commercial Off-the-Shelf (COTS) without compromising its performance capabilities. The obtained measurements show a colder behavior of the external elements with regard to the worst-case analysis during the first part of the ascent phase. In addition, radiative fluxes measured during the flight show a deviation in the infrared downward flux of about -50Wm at 5km of altitude and a maximum fluctuation of about the 20% in the solar fluxes measurements. Significant advancements have been made for similar missions in terms of mechanical standardization, the use of COTS sensors and electronic components, the improvement of the reliability of the thermal analysis and the development of a software design adhered to standards and recommendations for critical systems.

中文翻译：

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HERCCULES：BEXUS 32 的大学气球载实验，使用 COTS 来表征平流层的热环境

由于飞行阶段热环境的变化以及上升过程中的对流效应，平流层气球有效载荷的热分析仍然是一项复杂的任务。作为 REXUS/BEXUS 计划的一部分，一项名为 HERCCULES 的实验已于 2023 年 9 月在埃斯兰奇航天中心（瑞典基律纳）成功发射。该实验旨在作为传热和热环境表征平台，以验证先前开发的最坏情况热环境条件选择和这些平台的热分析方法。该实验是在学术环境下进行的，设计、制造、集成和测试活动主要由学士、硕士和博士完成。欧洲航天局指导的学生。通过使用商用现货 (COTS) 实现了低成本设计，且不影响其性能。获得的测量结果显示，在上升阶段第一部分的最坏情况分析中，外部元件的行为较冷。此外，飞行过程中测量的辐射通量显示，在5公里高度处，红外向下通量的偏差约为-50Wm，太阳通量测量的最大波动约为20%。类似任务在机械标准化、COTS 传感器和电子元件的使用、热分析可靠性的提高以及遵循关键系统标准和建议的软件设计开发方面都取得了重大进展。