电磁监测试验卫星（张衡一号）是中国地震立体监测体系的首个天基电磁平台，是中国地球物理场探测卫星计划首发星，用于获取地球磁场、空间电磁波场、电离层等离子体原位和结构参数及其变化信息，为探索地震前兆信息、空间环境监测预报和地球系统科学研究提供新的技术手段，为未来建立地震前兆电磁监测卫星业务化系统进行技术准备。介绍张衡一号卫星的系统设计、研制历程，特别卫星特殊的轨道设计、工作模式设计、磁电洁净度设计以及伸杆机构设计等关键技术特点。

China Seismo-Electromagnetic Satellite (CSES) is the first space-based electromagnetic platform of China’s stereo seismic monitoring system and the first satellite of China’s geophysical field exploration satellite program that will be used to obtain the in-situ structural parameters and their effects on Earth’s magnetic field, space electromagnetic wave field, and ionospheric plasma. According to the objective of CSES, the parameters of the satellite orbit, satellite platform, and payloads, including the satellite footprint, magnetic and charging cleanliness control and boom design, and the isoelectric potential on the platform surface, are analyzed and tested. On February 2, CSES was launched, and the commission test proved that the system works well. The entire team has overcome difficulties in the R&D phase. The platform and payload can work in orbit, and the preliminary test shows that the main function and performance meet the demand and index designed by the project.