Major Gordan Cooper is one of the original Mercury Astronauts and the last American to fly in space alone. On May 15, 1963, he shot into space in a Mercury capsule for an orbit journey around the world and reported one of the first Astronaut UFO Sightings.

During the final orbit, Major Gordon Cooper told the tracking
station located in Muchea, Australia that he could see a
glowing, greenish object ahead of him quickly approaching his
capsule. The UFO was solid and real, because it was picked up by
Muchea's tracking radar. The National Broadcasting Company, which was assigned the covering of the Gordan’s flight also reported the sighting; but when Gordan landed, reporters were told that they would not be allowed to question him about the UFO sighting. He experienced a similar incident some ten years earlier; in 1951 where he had sighted a UFO while piloting an F-86 over Western Germany. According to Gordan, he saw metallic, saucer-shaped discs at considerable altitude that could out-maneuver all American fighter planes.

Major Cooper even testified before the United Nations and told that he strongly believe that the UFO’s and aliens are visiting this planet from other planets. He concluded that there are quantity of documents and thousands of witness reports to prove this but the government does not want these reports to be public.

According to the NASA astronaut Neil Armstrong, aliens have a base on the Moon and they told us clearly to stay off from the Moon. According to un-confirmed reports, both Neil Armstrong and Edwin Aldrin saw UFO’s shortly after that historic landing on the Moon in Apollo 11 on 21 July 1969. According to a former NASA employee Otto Binder, unnamed radio hams with their own VHF receiving facilities that bypassed NASA's broadcasting outlets picked up the following exchange:

NASA: What’s there?
Mission Control Apollo11: These are huge, Sir! Enormous! OH MY GOD! You would not believe it! I am telling you there are other spacecraft out there, Lined up on the far side of the crater edge! They are on the Moon watching us!

Neil Armstrong relayed the message to mission control that three large, mysterious objects were watching them after having landed near the moon module. However, the public never heard this message because it was alleged that NASA censored it. According to a NASA employee who was a part of mission control, Aldrin even took color movie film of the UFO’s from
inside the module, and continued filming them after he and
Armstrong went outside. Armstrong confirmed that the story was
true but he refused to go into further detail, beyond admitting that
the CIA was behind the cover-up.