Recently, JiuZhou Yunjian "Longyun" 80-ton liquid oxygen methane engine completed the hot test of the whole machine at the engine test base built by itself, and the test was a complete success.

　　Longyun engine has three important features:

　　1. It has multiple starts and deep thrust adjustment capabilities. These two characteristics are the key basis for the rocket's recovery and reuse;

　　2. The engine envelope can meet the 3.35m diameter rocket layout with 5 engines, which facilitates the vertical recovery of the launch vehicle through the substantial throttling of the central engine;

　　3. The first domestic high-thrust liquid rocket engine without pyrotechnic device is friendly to use and easy to use and maintain.

　　In the follow-up, Longyun engines will be tested for multiple startups, thrust adjustments, and reliability to verify their recovery and reuse capabilities.