Time spent in zeroG changes the body: Astronauts come home with bone loss and weakness. But what happens in their heads?
失重会改变身体：宇航员回家时会有骨质流失和肌肉无力的感觉，但是他们的大脑里会发生什么呢？
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With the crew aboard the International Space Station packing up Endeavour for its return flight to Earth, several astronauts reflected on life in zero-G.