Thermal Control System Design and On-Orbit Validation for the 6U CubeSat SPHERE-1 EYE


In recent years, there has been an increase in smallsats and CubeSats performing complex missions in near-Earth and deep space environments. These complex missions require smaller sizes and higher performance in subcomponents, resulting in higher power densities and more difficult thermal design. In an Earth-orbiting satellite, the direct sunlight and eclipse phases repeat. This cycle is particularly intense for LEO satellites, and it is crucial to design satellites that take care of both the cold and hot sides. Generally, equipment keeps within its allowable temperature range through passive thermal control, such as changing surface characteristics or designing internal thermal paths. If it is still difficult to deal with, active control is performed by turning on heaters or changing the power status of equipment. The Intelligent Space Systems Laboratory (ISSL) at the University of Tokyo has developed two Earth-orbiting 6U CubeSats with a versatile bus system. One is SPHERE-1 EYE, whose mission is to capture images at will by general users. The other is ONGLAISAT, whose mission is to perform Earth remote sensing using Time Delay Integration (TDI) technology. This paper introduces the design of the thermal control system, including the hardware and software of SPHERE-1 EYE. A thermal design description of SPHERE-1 EYE, including requirements, thermal hardware accommodation, and thermal control algorithms in software, is presented. It also describes the checkout procedures for thermal hardware during a limited pass time and on-orbit thermal condition, including initial temperature control by battery heater and checkout status of temperature sensors.


Kazuki Takashima, The University of Tokyo, Japan
Shingo Nishimoto, The University of Tokyo, Japan
Yuki Kusano, The University of Tokyo, Japan
Kazuki Toma, The University of Tokyo, Japan
Toshihiro Shibukawa, The University of Tokyo, Japan
Shinichi Yokobori, The University of Tokyo, Japan
Akihiro Ishikawa, The University of Tokyo, Japan
Shuhei Matsushita, The University of Tokyo, Japan
Ryu Funase, The University of Tokyo, Japan
Shinichi Nakasuka, The University of Tokyo, Japan
ICES107: Thermal Design of Microsatellites, Nanosatellites, and Picosatellites
The 52nd International Conference on Environmental Systems was held in Calgary, Canada, on 16 July 2023 through 20 July 2023.


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