| 1. | This method not only wastes cryogenic fuel , but also causes safety problem . it is necessary to develop new type of precooling method , so the natural circulation cooling system is introduced
因此，为节约推进剂，提高发射的可靠性，简化地面系统以及发射前的操作程序等，需要立即开展新型的自然循环预冷法的研究。 |
