by Gary Li, Danielle DeLatte, Jerome Gilleron, Samuel Wald, Therese Marie JonesForty-five years have passed since humans last set foot on an extraterrestrial body....
To get into orbit, a rocket has to be traveling 11 kilometers a second — 25, 000 miles per hour!...
That fuel is heavy — and getting it moving at such high speeds takes a lot of energy....
综合
美国兰德公司-赛博战专栏
2017-05-17 00:00:00.0