大気球飛翔環境下での高精度変位計測装置の実証報告: DREAM4

To improve observation performance, for example in X-ray observations, it is important to enhance the alignment accuracy of observation instruments. Addressing the challenge of maintaining the precise shape of large structures—a key requirement for improving alignment accuracy—our group has been developing a displacement measurement system. In this study, on June 20, 2025, we conducted a balloon experiment (B25-03) with a total flight duration of 2 hours and 50 minutes, during which the system measured the displacements of meter-scale structures. As a result, we confirmed that the displacement measurement system functioned properly under the balloon flight environment (low temperature, low pressure, solar exposure, and noise from other instruments). Furthermore, the estimated displacements based on pre-flight tests and in-flight temperature data agreed with the measured displacements within an accuracy of ±100 μm, demonstrating that the pre-flight tests enabled reliable prediction of in-flight displacements. However, differences were found between the finite element analysis (FEA) results and the experimental results, which require further investigation.