为了考察月面高温环境下液体火箭发动机的工作能力，开展了双组元120 N自燃推进剂发动机高空模拟热试车，通过包覆热控组件和添加比例积分微分控制装置实现了对推进剂供应管路和电磁阀壳体的加热和保温，研究了常温和80~135 ℃保温对发动机点火时的稳态工作性能、脉冲工作性能的影响，验证了保温后进行长脉宽脉冲程序点火排出汽化推进剂的可行性。试验结果表明：各个高温条件下，发动机均可实现稳态和脉冲模式工作，稳定后稳态工作性能相当，基于推力测量的启动响应时间较常温条件下明显延长，关机时恢复至正常水平。受推进剂密度和四氧化二氮气液流动状态的综合影响，在保温80、90、105、120、135 ℃时，30 ms脉宽下首个脉冲推力冲量相对常温条件下的占比分别为80%、66%、31%、16%、17%。当脉宽小于或者大于启动响应时间时，推力冲量相较常温下的偏差值随脉宽增大均逐渐缩小。7组128 ms脉宽的脉冲程序可以基本排净推进剂供应管路内汽化的推进剂，排气程序结束后发动机脉冲工作性能恢复至正常水平。

To investigate the working capability of liquid rocket engines in the high temperature environment on the lunar surface， the high-altitude hot fire simulation test of a 120 N bipropellant rocket engine using hypergolic propellants is conducted. The thermal control assembly and the proportion integration derivative control device are used to control the heating and holding temperature of the propellant supply lines and solenoid valve housing. The effects of the holding temperature at normal atmospheric temperature and 80–135 ℃ on the steady-state and pulse working performance of the engine ignition are investigated. The feasibility of discharging the vaporized propellant through the long-pulse ignition procedure after holding is verified. The test results show that the engine can operate in both the steady state and the pulsed mode under all high temperature conditions， with comparable steady-state working performance after stabilization. The start-up response time based on thrust measurement is significantly longer than that under normal atmospheric temperature conditions， and returns to normal level at shutdown. Affected by the combined effect of the propellant density and the nitrogen tetroxide gas-liquid flow state， the first pulse thrust impulse at 30 ms pulse width relative to the normal atmospheric temperature condition is 80%， 66%， 31%， 16% and 17% at holding temperatures of 80 ℃， 90 ℃， 105 ℃， 120 ℃ and 135 ℃， respectively. When the pulse width is smaller or larger than the start-up response time， the deviation value of the thrust impulse compared with that at normal atmospheric temperature gradually decreases with increasing pulse width. The 7 sets of 128 ms pulse width can basically drain the vaporized propellant in the propellant supply lines， and the engine pulse working performance returns to the normal level after the exhaust procedure.