Yuri Gagarin was the first man in space (and also the first man to wear a watch in space), but he died a few years later, when his MIG crashed during what was thought to be a routine training flight. This article explores this crash.
http://www.telegraph.co.uk/news/worldnews/europe/russia/6946383/Yuri-Gagarin-death-mystery-solved-after-40-years.html
When we read this article, perhaps we can understand better why President Kennedy "grounded" John Glenn from future flights, after he became the first American to orbit the earth in space. Gleen was such a hero that Kennedy did not want to take the risk that he could be killed during a subsequent flight. Of course, he flew many years later, aboard the Shuttle, but this was well after the years when his flight was such a sensation.
Jeff
