In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
One example is below.
Q: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world. 
 Answer: 10,000,000 or less.
A: How many books are there in the British Library?
Rationale: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.
Q: Article: Human beings have a natural desire to explore the unknown. People with a strong interest in space like to say it is the last place left to explore. But scientists are warning that space exploration for long periods is not going to be easy. They say the human body is not designed to stay in space over an extended period. The New York Times recently published a report about scientists who are preparing astronauts for a trip to the Moon. The newspaper said the scientists want to make sure that their crews return home in good health. But there are many problems to be solved before people are ready for long trips to the Moon, an asteroid or even the planet Mars. Humans developed on a planet with a surface that is more than 70 percent water. Our bodies are also about 70 percent water. When there is no gravity that water moves up toward the head, raising pressure in the skull. Arms and legs grow weaker at what is called zero gravity because they no longer need to push against the force of gravity. Five years ago, astronauts who spent weeks in space reported a change in their eyesight. These astronauts were members of the crew on the International Space Station. Research showed a change in the shape of their eyes. Normally-round eyeballs had become flat during time in space. The research also showed that the right eye was affected more than the left, and that men were more affected than women. Scientists could not find an explanation for the differences. Bone loss was one of the problems first reported by astronauts returning to Earth after longer stays in space. So scientists designed exercise machines to use on the space station. Tests showed that the exercise equipment helped space travelers keep their bones almost as strong as when they left Earth. There are other health issues for astronauts who spend a long time in space. They may have problems eating and sleeping. But the biggest health issue is exposure to radiation. On Earth, human beings are protected by the atmosphere and the planet's magnetic field. In outer space, there is no such protection. 
 Answer: Long periods in space will affect the health of astronauts.
A:
What is the main idea of the passage?