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许多年以来,美国航宇局(NASA)为了促进航天飞机的发展,几乎淘汰了美国的常规运载火箭。但是,挑战者号航天飞机爆炸的悲剧表明了航天飞机尚不成熟,因此,航天飞机的商业飞行被取消,常规火箭则焕发了青春。美国空军目前是美国重新采用常规火箭的主要倡导者。最近,美国空军为满足军用需要,订购了德尔它、大力神2和大力神4火箭。这使得美国火箭制造商重新涉足于商业发射市场。马丁·马丽埃塔公司已成功地推销了两枚大力神3火箭,迈出了第
For many years, NASA has nearly phase-out U.S. conventional launch vehicles in order to facilitate the development of the space shuttle. However, the tragedy of the Space Shuttle Challenger space shuttle shows that the space shuttle is not yet mature. As a result, commercial flights of the space shuttle were canceled and conventional rockets rejuvenated. The U.S. Air Force is currently the main advocate of U.S. re-use of conventional rockets. Recently, the U.S. Air Force ordered Deltas, Hercules 2 and Hercules 4 rockets to meet military needs. This makes the United States rocket manufacturer re-enter the commercial launch market. Martin Marietta has succeeded in marketing two Hercules 3 rockets, taking the first place