自古以来,人类一直梦想进入太空。可是,进入太空大门的钥匙在哪里?19世纪末20世纪初,人类积累了一定的科学知识和技术,终于找到了打开太空大门的钥匙。由于受地球引力的牵制,航天器要在冲出大气层后环绕地球运行,必须达到每秒7.9千米的第一宇宙速度;若要飞向月球,必须达到每秒10.8千米的速度;要环绕太阳运行, Since ancient times, mankind has always dreamed of entering space. However, where is the key to entering the space gate? In the late 19th and early 20th century, humans accumulated certain scientific knowledge and techniques and finally found the key to opening the space gate. Due to the gravitational pull of the Earth, the spacecraft must run around the Earth after it has exited the atmosphere and must reach a first cosmic speed of 7.9 kilometers per second; it must reach a speed of 10.8 kilometers per second if it wants to fly to the moon; Sun run,