Experimental study of a smart radiator device (SRD) for enhanced passive thermal control of small satellites

小型航天器由于其成本低、外形小和发射成本低，在各种轨道应用中越来越受到公司和研究人员的欢迎。 小型航天器在低地球轨道的应用包括地球观测、空间科学甚至互联网数据回传。 空间系统的小型化对大多数分系统都是一个挑战，包括热控和电源分系统。 由于太阳能电池的可用面积有限，电源子系统设计人员需要仔细检查每瓦的消耗。 为了最大限度地提高动力子系统的效率，热工程师试图避免对加热器的需求，因为加热器的功率可以更好地用于为有效载荷和其他航天器系统提供动力。 然而，由于热控制工程师必须为最坏情况下的热场景确定散热机制（散热器）的大小，大多数航天器需要为所有其他（较冷）热场景提供补充加热器，因为传统的散热器具有固定的发射率和面积。 为了解决这个问题，MPBC开发了一种新型的航天器散热器，称为智能散热器设备（SRD），它可以随温度变化而改变其发射率。 SRD在低温下比高温下辐射更少的热量。 如果大小和调整得当，SRD可以最大限度地减少或消除对许多航天器加热器的需求，因为当航天器冷却下来时，散热器会有效地关闭。 Magellan Aerospace对SRD技术作为航天器热控制的创新手段感兴趣，但在建模或将SRD集成到航天器方面没有任何经验。 本研究项目的目的是评估小型卫星SRD面板的可行性。 我们将热模型SRD面板和验证模型中的热真空室测试。 我们还将量化SRD提供的节能和热控制改进。 这项研究将使未来的卫星设计师将SRD纳入他们的设计，使用该项目中开发的模型和热控制策略。 通过这样做，由于更精确的热控制和对补充加热器功率的需求减少，航天工业将能够获得更广泛的设备和有效载荷。

Small spacecraft are becoming popular for companies and researchers for a wide range of orbital applications, due to their reduced cost, small form-factor and low launch costs. Applications of small spacecraft in low earth orbit include earth observation, space science and even internet data back-haul. Space systems miniaturization is a challenge for most subsystems, including the thermal control and power subsystems. With limited area available for solar cells, power subsystem designers need to scrutinize every watt of consumption. To maximize the power subsystem efficiency, thermal engineers try to avoid the need for heaters, since heater power could better be used to power payloads and other spacecraft systems. However, since thermal control engineers must size heat dissipation mechanisms (radiators) for the worst-case hot scenarios, most spacecraft require supplemental heaters for all other (colder) thermal scenarios, since traditional radiators have a fixed emissivity and area. To remedy this, MPBC has developed a new type of spacecraft radiator known as the Smart Radiator Device (SRD) that changes its emissivity with temperature. The SRD radiates less heat at cold temperatures than at hot temperatures. If sized and tuned properly, the SRD could minimize or eliminate the need for many spacecraft heaters because the radiator would effectively turn itself off when the spacecraft cools down. Magellan Aerospace is interested in the SRD technology as an innovative means of spacecraft thermal control, but does not have any experience in modelling or integrating SRDs into spacecraft. The purpose of this research project is to evaluate the feasibility of an SRD panel for small satellites. We will thermally model an SRD panel and verify the model in a thermal-vacuum chamber test. We will also quantify the power savings and thermal control improvements the SRDs provide. This research will enable future satellite designers to incorporate SRDs into their designs, using the models and thermal control strategies developed in this project. By doing so, the space industry will have access to a wider range of equipment and payloads, thanks to the more precise thermal control and the reduced need for supplemental heater power.