# Fault Prediction for Rotating Mechanism of Satellite Based on SSA and Improved Informer
## 2 Background  
The space turntable is a crucial component for realizing payload functions. Its reliability not only affects the normal execution of payload functions but also plays a significant role in maintaining the satellite's attitude stability due to the large inertia components it drives and the despinning functions it performs [21]. The satellite turntable subsystem is an essential part of the satellite spatial rotation mechanism that is used to control the direction and angle of the satellite turntable to ensure that the satellite antenna is aligned with the desired ground station. The turntable subsystem primarily consists of the turntable body, the turntable electronic control box, balance wheels, the locking and release mechanism, and supporting software. The structural form of the turntable body is shown in Figure 1. The base is thermally insulated and mounted on the top surface of the satellite platform module, with the bearing housing encased by the payload module. The support shaft system uses a pair of back-to-back angular contact ball bearings, preloaded during installation. The shaft system employs a parallel configuration with bearings located outside the entire turntable. Inside the bearing space, from top to bottom, conductive slip rings and torque motors are sequentially installed. The satellite rotation mechanism links the payload and platform modules, enabling smooth, high-speed rotation while transmitting power and signals. The platform module supplies power and commands to the payload via the slip ring assembly, while the turntable subsystem sends rotational angle data back to the payload manager. Figure 2 illustrates these connections and control relationships. The stability of the turntable temperature is crucial for ensuring the effective operation of the satellite rotation mechanism. It is influenced by several factors, including the turntable motor current, the satellite's attitude and orbit, and the position of the sun. Firstly, the different operational modes of the entire satellite necessitate varying operational modes for the turntable, resulting in different operating conditions. During these conditions, the turntable motor generates a certain amount of current, which in turn produces heat within the motor. Excessive current or poor motor cooling can lead to an increase in the turntable temperature [22]. Secondly, the satellite's attitude and orbit also impact the turntable temperature. Adjustments and movements of the satellite's attitude in space impose different thermal loads on the turntable under various operating states. Therefore, when studying turntable system faults, it is crucial to consider the satellite's attitude characteristics and adjust the turntable's temperature thresholds to maintain an appropriate temperature under various attitude and orbital conditions. Additionally, the position of the sun significantly affects the turntable temperature. Solar radiation is one of the main heat sources, and direct exposure to the turntable can cause its temperature to rise. Consequently, the angle and intensity of solar exposure need to be considered in different satellite missions and working environments. Among these factors, the current of the turntable motor is relatively easy to detect and analyze numerically. Hence, this study aims to quantify the variations in the turntable motor current and analyze its impact on the turntable temperature. Based on the current variation patterns, this paper predicts turntable temperature faults to enable timely adjustments and repairs. By thoroughly investigating the relationship between turntable current and temperature, this study allows us to better understand the operational state and performance characteristics of the turntable and anticipate potential temperature faults in advance. This enables effective control and management of the turntable temperature, which is crucial for enhancing the reliability and performance of the turntable and ensuring the normal operation of the satellite. Figure 1: Structure ofturntable body.