Thermal Design and On-Orbit Data Evaluation of the 3U-class CubeSat TRICOM-1R, Correlation Analysis between the Attitude and Thermal Measurement

This paper describes the thermal design and on-orbit evaluation results of 3U-class nanosatellite TRICOM-1R. TRICOM-1R is the substituting satellite of TRICOM-1, which could not be in the orbit with the launcher failure. TRICOM-1R was launched by SS-520-5 sounding rocket (ISAS/JAXA), and successfully inserted into the orbit on 3, February 2018 and operated for a half year. The satellite has some uniqueness points. At first, the development period was very short. Therefore, the development team skipped the evaluation in the experiment under the thermal vacuum environment for TRICOM-1R and utilizes the TRICOM-1 thermal mathematical model because it can be considered as compatible between TRICOM-1 and TRICOM-1R. Second, the insertion orbit has high eccentricity (0.12) and very low perigee altitude (about 180 km). The sun/eclipse duty ratio has the difference from the typical low earth orbit satellite. The orbit and attitude profile were affected from atmospheric drag. Finally, the satellite separated with high angular rate and it experienced variable attitude changes. In the beginning, the satellite was spin stabilized but it changed the spin axis during the operation because of its energy dissipation. The satellite mounts poor attitude sensors and there had some difficulties to estimate exact attitude. This paper performs the calibrations of the thermal-mathematical model and discusses the reason for the differences with the pre-launch model. For this purpose, the attitude estimation data is also updated with the help of the thermal measurement data, together with the thermal properties calibration. The analysis results with the established model show the acceptable differences from on-orbit measurement data. The reason of the differences are discussed and summarized to utilize for the design and analysis of the similar satellite development.