常見例句The bottom unit consisted essentially of four landing struts equipped with a retrorocket to cushion the descent. 下節(jié)登月艙實際上是由四個登陸支柱和減速火箭所組成的，而減速火箭是在登陸時用來減低沖力的。High-Impulse Retrorocket System 高沖量制動火箭系統(tǒng)retrorocket unit 制動火箭發(fā)動機 返回 retrorocket