490N液体火箭发动机被广泛使用于航天器远地点机动入轨或者为其他轨道机动提供推力。我国第一代490N发动机真空比冲为304.7s，曾经成为制约我国航天器寿命上台阶的技术瓶颈，因此开展了基于铌合金材料的高性能第二代490N发动机研制工作，比冲提高10s。对第二代490N轨控发动机的研制和在轨飞行验证结果进行了总结和分析。第二代490N发动机研制过程中突破了高性能喷注器、耐高温材料及涂层、发动机头部喷注器法兰和燃烧室壁面结构温度控制、抗高量级力学环境能力以及热防护罩等多项关键技术，真空比冲达到了317.8s，单台发动机累计199次启动工作寿命40000s以上，工作性能达到国际同等水平。

The 490N liquid apogee engines have been widely applied for the maneuvering into orbit of apogee spacecrafts or providing thrust of other orbital maneuvers. The vacuum specific impulse of the first generation 490N engine in China is 304.7s, which has become the technology bottleneck restricting the life of spacecraft in China. Therefore, the development of the second generation 490N engine with high performance based on niobium alloy materials has been carried out, and the aim of the specific impulse increased by 10s. The development of the second generation 490N orbit control engine and the results of on-orbit flight verification are summarized and analyzed. During the development of the second generation 490N engine, many key technologies include high performance injector, high temperature resistant material and coating, temperature control of head flange and wall structure of combustion chamber, high-level mechanical environment resistance and thermal shield. The vacuum specific impulse has reached up to 317.8s, the cumulative starting life of a single engine has reached up to more than 40000s and it had 199 start-ups, and the working performance has reached the international advanced level.

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