Read the selection and choose the best answer to each
question.
Going Into Space is Trouble
by Michael Signal
1 Many people have dreamed about blasting into space, but it is not something many people have had the chance to do. The first challenge in getting to space is just becoming an astronaut. The next challenge is actually launching humans into space. Every space launch is dangerous and difficult. But the problems don't end for astronauts, even when they reach orbit around the Earth or dock with a space station. One of the other major problems with space travel is the human body itself. It does not belong in space. That is one reason it is so hard to get picked to become an astronaut. Since space travel takes a serious toll on a person's health, only the healthiest people have any chance of being picked to ride a rocket into space.
2 NASA is the world's most famous space agency. It only recruits astronauts every few years. NASA gets thousands of astronaut applications during each recruitment period, but it is very selective. Only about a dozen of those applicants will become astronauts. In NASA's early days, the first astronauts were all hot-shot military pilots. Military pilots still make up a large part of NASA's astronaut crews, but so do scientists. Along with the physical and intellectual requirements it takes to become an astronaut, NASA also considers candidates' skills and scientific expertise. One of the most important reasons for space travel is for scientific research. So NASA also selects many astronauts from the scientific community. Of course, NASA only considers the top scientists in their fields.
3 Space travel is far from safe. NASA and other space agencies do everything they can to keep astronauts safe, but rockets travel over 17,000 miles per hour. They are fueled by tons of explosive propellants. They carry humans to a barren environment of dangerous radiation, extreme temperatures, and no air. A lot could go wrong, and sometimes it does. American astronauts have died in training, traveling into orbit, and returning to Earth. Other countries have also lost astronauts to fatal accidents. Space agencies make space travel as safe as they can, but it will never be completely safe.
4 Getting into space safely doesn't mean an astronaut is out of the woods. Spending time in space brings its own set of problems. Exposure to the zero-gravity of space has negative effects on the human body. One minor effect of zero gravity is vomiting. Not all astronauts get this space sickness, but throwing up is never pleasant. Imagine doing it while you (and the vomit) are floating and weightless. There are other, more serious side effects of space travel though. In the weightlessness of space, all people actually start to lose bone and muscle mass. Scientists even think that the lack of gravity can make a person's eyesight worsen. The effects increase as astronauts stay in space for longer periods of time. So even though astronauts leave Earth in peak physical shape, they won't be quite as healthy when they return.
5 Only a select few people on the entire planet will ever become astronauts. It is very hard to become an astronaut with any space agency, but becoming an astronaut is not the danger. Sitting on top of a rocket, ready to explode up into space is very dangerous. Traveling past the Earth's atmosphere at thousands of miles per hour is not safe either. Getting into space is nearly impossible, and it's not a safe or healthy place to be in space. Space travel makes the human body weaker. You might think that all those factors would make more people decide against applying to become astronauts, but you would be wrong.