当宇航员返回地球后,长时间的太空飞行可使其健康出些问题。俄国人创下了在太空逗留最长时间(超过一年)的纪录。同时他们也花费了最多的时间,在失重和受限制的太空旅行中,对人类长时间生存的能力进行实验。最近美苏联合实验显示,老鼠的骨骼强度及肌力都受到严重的损失。 After astronauts return to Earth, prolonged space flight can cause problems with their health. The Russians set the record for the longest stay in space (more than a year). At the same time, they also spent the most time experimenting with the long-term survival of humankind in weightless and restricted space travel. Recent United States-Soviet joint experiments showed that the strength of the bones and muscle strength of mice suffered serious losses.