This is just a quick over view of astronauts who claim to have seen UFOs at one point or another.
Some of these are rather famous and it may surprise you at their comments.
Donald Slayton -
Donald Slayton, a Mercury astronaut, revealed in an interview he had seen UFOs in 1951: "I was testing a P-51 fighter in Minneapolis when I spotted this object. I was at about 10,000 feet on a nice, bright, sunny afternoon. I thought the object was a kite, then I realized that no kite is gonna fly that high." As I got closer it looked like a weather balloon, grey and about three feet in diameter. But as soon as I got behind the darn thing it didn't look like a balloon anymore. It looked like a saucer, a disk. About the same time, I realized that it was suddenly going away from me - and there I was, running at about 300 miles per hour. I tracked it for a little way, and then all of a sudden the damn thing just took off. It pulled about a 45 degree climbing turn and accelerated and just flat disappeared."
Robert White -
On July 17, 1962 Major Robert White reported a UFO during his fifty-eight-mile high flight of an X-15. Major White reported: "I have no idea what it could be. It was grayish in color and about thirty to forty feet away."
Then according to a Time Magazine article, Major White exclaimed over the radio: "There ARE things out there! There absolutely is!"
Joseph A. Walker -
On May 11, 1962 NASA pilot Joseph Walker said that one of his tasks was to detect UFOs during his X-15 flights. He had filmed five or six UFOs during his record breaking fifty-mile-high flight in April, 1962. It was the second time he had filmed UFOs in flight. During a lecture at the Second National Conference on the Peaceful Uses of Space Research in Seattle, Washington he said: "I don't feel like speculating about them. All I know is what appeared on the film which was developed after the flight." - Joseph Walker To date none of those films has been released to the public for viewing.
Eugene Cernan -
Eugene Cernan was commander of Apollo 17. In a Los Angeles Times article in 1973 he said, about UFOs: "...I've been asked (about UFOs) and I've said publicly I thought they (UFOs) were somebody else, some other civilization."