Rocket propellant has barely changed in the more than 50 years since the launch of the first artificialsatellite Sputnik.
自第一颗人造卫星史泼尼克发射以来,火箭推进剂在超过50年的时间内变化不多。
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Sputnik - the first artificialsatellite - is launched by the Soviet Union on October 4, 1957, as a global positioning system for precise weapon delivery and paves the way for GPS as we know it today.