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

小型航天器因其成本低、外形小和发射成本低而受到公司和研究人员的欢迎，用于广泛的轨道应用。小航天器在近地轨道上的应用包括地球观测、空间科学，甚至互联网数据回传。空间系统小型化是包括热控和动力子系统在内的大多数分系统面临的挑战。由于可用于太阳能电池的面积有限，电源子系统设计者需要仔细检查每一瓦的消耗。为了最大限度地提高动力系统的效率，热工程师试图避免使用加热器，因为加热器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，由于热控工程师必须为最恶劣的高温情况确定散热机构(散热器)的大小，因此大多数航天器需要为所有其他(较冷的)热情况补充加热器，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)，它可以随着温度变化发射率。SRD在低温下比在高温下辐射的热量更少。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，因为当航天器冷却时，辐射器会有效地自动关闭。麦哲伦航天公司对将SRD技术作为航天器热控制的一种创新手段感兴趣，但在将SRD建模或将SRD集成到航天器方面没有任何经验。这一研究项目的目的是评估小卫星SRD面板的可行性。我们将对SRD面板进行热建模，并在热真空室测试中验证模型。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者能够利用该项目开发的模型和热控制策略，将SRD纳入他们的设计。通过这样做，航天工业将能够获得更广泛的设备和有效载荷，这要归功于更精确的热控制和减少对补充加热器动力的需求。

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.