In response to the need for a space security situation assessment during orbit, the multi-satellite space environmental risk prediction and early warning system is based on the detection results of the space weather payload of the Fengyun 4A and 4B satellites, as well as the prediction results of the National Space Weather Center, for the first time. By comprehensively utilizing some open-source data, it is the first time that we have achieved a 24 h advanced prediction of the space environment high-energy proton, low-energy particle, and high-energy electron risks for the safety of the Fengyun-series high-orbit satellites, and a real-time warning of satellite single-event upset, surface charging, and deep charging risks. The automation system has preliminarily achieved an intelligent space risk assessment for the safety of multiple stationary meteorological satellites, effectively improving the application efficiency of the space environmental data and the products of Fengyun-series satellites. The business status is stable in operation, and the resulting error between the predicted results of various risk indices and the measured data was less than one level. The warning accuracy was better than 90%. This article uses the system for the first time, to use Fengyun satellite data to, accurately and in a timely manner, predict and warn us about the low-energy particles and surface charging high-risk levels of the Fengyun 4A and 4B satellites during the typical space weather event on 21 April 2023, in response to the impact of complex spatial environmental factors on the safety of Fengyun-series high-orbit satellites. The construction and operation of a multi-satellite space environmental risk prediction and early warning system can provide a reference for the safety work of subsequent satellite ground system operations.

We introduce a novel Rayleigh Doppler lidar (RDLD) system that utilizes a high-power single-frequency laser with over 60 W average output power, achieved through fiber solid-state cascade amplification. This lidar represents a significant advancement by addressing common challenges such as mode hopping and multi-longitudinal mode issues. Designed for atmospheric wind and temperature profiling, the system operates effectively between altitudes of 30 km and 70 km. Key performance metrics include wind speed and temperature measurement errors below 7 m/s and 3 K, respectively, at 60 km, based on 30 min temporal and 1 km spatial resolutions. Observation data align closely with ECMWF reanalysis data, showing high correlation coefficients of 0.98, 0.91, and 0.94 for zonal wind, meridional wind, and temperature, respectively. Continuous observations also reveal detailed wind field variations caused by gravity waves, demonstrating the system’s high resolution and reliability. These results highlight the RDLD system’s potential for advancing meteorological monitoring, atmospheric dynamics studies, and environmental safety applications.

The FY-4B satellite is one of the second generation of China’s geosynchronous meteorological satellites aiming at numerical weather forecasts. The space environment monitoring package (SEMP) onboard the FY-4B is a comprehensive instrument package for plasma, high-energy particle, and energetic neutral particle measurements. The low-energy particle analyzer (LEPA) is one of the instruments of the SEMP and consists of two top hat electrostatic analyzers designed for plasma detection. The electron and ion sensors are back-to-back assembled and are integrated to a shared electronic box. It measures the three-dimensional velocity distribution of low-energy electrons and ions on the geosynchronous orbit. In this paper, we present the ground calibration and in-flight performance of the instrument. With the electrostatic deflectors and the cylindrically symmetric structure, the instrument provides high-cadence measurements of electron and ion velocity distributions with a wide field of view (FOV) of 180° by 100°, an angular resolution of 16.7° × 20°, and a broad energy range for both the electrons and ions from tens of eV to above 30 keV, with a 1 s time resolution. The geometric factors of the electron and ion analyzers are 1.1 × 10⁻³ cm²·sr·eV/eV and 1.4 × 10⁻³ cm²·sr·eV/eV, respectively, which fulfills the requirements of the low-energy plasma measurement. The LEPA monitored typical space environment disturbance such as geomagnetic storms and successfully recorded the responses of plasma energy fluxes. Satellite surface charging events were measured, with the highest potentials of −2000 V in the shadow period and −500 V in the nonshadow period.

This article introduces the instrument design of the medium energy proton detector (energy range: 30 keV–5 MeV) mounted on the FY-3E satellite. Through the design and optimization of the sensor signal processing circuit, the anti-electromagnetic interference ability of the medium energy particle detector is greatly enhanced. The designed aluminum plating on sensors can effectively exclude the light pollution to the medium energy protons. The designed permanent annular magnet has a deflection efficiency of more than 95% for medium energy electrons below 1.0 MeV. Additionally, by designing the logical working mode of the sensor, the contamination by other high energy particles (high energy electrons > 1.5 MeV, high energy protons > 5 MeV, and heavy ions) is excluded. Combining the above methods, the detector achieves the detection lower limit of 30 keV for medium energy protons. Its energy resolution is better than 15%@100 keV and the mixing ratio of electrons is less than 2%.

The radiation damage effect is relatively serious during spacecraft operation in orbit. To know the real cumulative dose in orbit accurately, a radiation dose detector is carried on the FY-4B satellite. It comprises one electric control unit and three dose detectors, with a total of four payloads. Each dose detector includes five dose-monitoring points corresponding to different shielding thicknesses, which are mainly used for the measurement of the dose depth. Three dose detectors with the same function are installed in the X, Y and Z positions and can detect the total dose in different directions during the operation of the satellite. Each detector has the characteristics of small size, high integration and low power consumption. At present, the FY-4B satellite is in orbit. The detectors have been working normally since they were started up, and good preliminary detection results have been obtained. From the power-up of the detectors to April 2022, the maximum dose has reached 2.7 × 10³ rad(Si). We conducted a preliminary analysis of the relationship between total dose and shielding thickness. In addition, the relationship between daily average dose and shielding thickness was further analyzed. These studies have application value for radiation protection design.

Alfven-branch waves provide an efficient means for transporting energy into the auroral oval. Here, we report observations of these waves obtained by the Fengyun-3E (FY-3E)/ACMag instruments, which are designed to detect three-dimensional AC magnetic fields in the 0.05–25 Hz band. The observations suggest that broadband waves are a permanent feature of the auroral oval, although their amplitude and locations vary with the global state of the magnetosphere. We primarily focus on the data obtained from 10 July 2021 to 26 August 2021, during which a series of recurrent storms driven by solar wind corotating interaction regions (CIRs) occurred. Analysis of the observations shows that the auroral-oval waves grow in amplitude (1–3 orders of magnitude) and shift to lower latitude (∼10°) immediately following the decrease in the SYM-H index in each storm. Further investigation reveals the response of the auroral-oval waves has a time scale equal to or less than FY-3E’s effective revisiting time, which is about 45 min. The observations presented in this paper confirm that the FY-3E/ACMag instruments provide a high-resolution monitor of the auroral-oval waves and could further our understanding of auroral physics.