Human beings have been interested in what lies outside the Earth since the dawn of time. People were curious about what zero gravity would be like and what it would do to the human body. Valerie Neal, curator and chair of space history at the Smithsonian National Air and Space Museum, said, “All those normal things that we take for granted, no one was sure what was going to happen” (Smithsonian). At first, scientists sent simple organisms such as mice, dogs, and monkeys into space. Now, thanks to the study of space exploration, scientists are able to send living people to the Moon and beyond. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay After John Glenn became the first person to orbit the Earth and Neil Armstrong set foot on the moon, there was a new vision of what space did for the human body and there were new inventions in space medicine. Space medicine is the development of technologies designed to keep astronauts alive and well in space, and medical experiments performed in orbit to take advantage of the unique environment in space (Leslie). They realized that astronauts can lose bone mass, can have heart and circulatory problems, and brain function can decline. These are just some of the negative effects that space can have on the human body. The human skeletal system is the primary support system, storing key nutrients, producing blood, and protecting many vital organs. In space, astronauts are prone to bone loss. This may not be a big problem while in space, but upon returning to Earth there may be a greater risk of fractures and ruptures. When astronauts travel in space, the weight supported by their bones is drastically reduced. This causes their bones to become weak and begin to deteriorate. A noticeable change occurs when calcium stored in the bones begins to be released into the bloodstream when the bones are not used as usual. This phenomenon is similar to the osteoporosis disease that people experience on Earth when they do not use their muscles and bones properly. The most undeniably present change in bone mass occurs between two and five months in space. Some astronauts on the Mir spacecraft lost up to 20% of their bone mass (Dunbar). John Uri, a mission scientist for the shuttle-Mir cooperation program, found that the spine, legs and hips tend to lose more bone mass than anywhere else. (NBC, 1998) To date, we still don't know the exact cause of osteoporosis upon returning from space. Fortunately, several scientists from the United States and Canada have worked out and concluded that the best way to keep most of your bone mass intact is to do weight-bearing exercises such as walking, jogging, volleyball, and basketball (Canadian Space Agency). These recreational activities can also increase your heart rate, keeping your heart pumping and your blood pumping strongly. The heart and circulatory system are another important factor in keeping people alive and healthy in space. Staying in space for extended periods of time can cause heart problems when returning to Earth. In space, the heart physically changes shape. On Earth, the heart is more like an oblong oval, and when it is in space, after a while it becomes more like a sphere. "The heart in space works less, which can cause a loss of muscle mass. This can have serious consequences after returning to Earth, so we are examining,.