Dr. Edgar Mitchell, the 6th man to walk on the moon, told a radio station yesterday that he knows for a fact that space aliens exist and have visited Earth. From Wikipedia:
On July 23, 2008 Edgar Mitchell was interviewed on Kerrang Radio. Mitchell claimed the Roswell crash was real and that Aliens have contacted humans several times but that governments have hidden the truth for 60 years stating "I happen to have been privileged enough to be in on the fact that we've been visited on this planet and the UFO phenomena is real". In reply, a spokesman for NASA stated "NASA does not track UFOs. NASA is not involved in any sort of cover up about alien life on this planet or anywhere in the universe. Dr Mitchell is a great American, but we do not share his opinions on this issue."