In the future, more space missions will be put on the agenda, and thus astronauts will spend more time in space. Understanding the effects of long-term space travel will be more than beneficial to help scientists design and modify countermeasures to conquer space hazards for astronauts. This research paper illustrates the negative effects of long-term spaceflight. Microgravity in space causes a decrease in bone density. Some astronauts are prone to get bone fractures after their space mission; some astronauts have to lay on the stretcher after landing. Such phenomenons let scientists make assumption that long time space travel may decline bone density of human beings. Since observing the change in distribution of bone density requires a long time …show more content…
Lack of gravity can cause the heart to be reshaped, becoming spherical like a ball. The round heart shape may increase the rate of cardiovascular disease[6]. Due to microgravity, after only two weeks in the space, the aerobic ability of the heart is lessened, compared with when on earth[7]. Because of weakened heart function, some astronauts have extremely low blood pressure after going back to earth; some people faint after stepping out the spacecrafts; some people have abnormal heart