Buzz Aldrin, the second man on the moon, and four others gave accounts of their sightings under strict lab conditions.
According to Aldrin, Al Worden, Edgar Mitchell and Gordon Cooper all took part in the study conducted by the Institute of BioAcoustic Biology in Albany, Ohio.
The tests, reportedly more reliable than standard lie detector tests, showed he was telling the truth, the reported.
Apollo 15 pilot Worden, 85, and Apollo 14’s Mitchel also claimed to have seen UFOs while Cooper says he actually tried to chase a cluster of objects.
Tests analysing their voice patterns suggested they were also telling the truth about their strange encounters.
Aldrin answered questions about his alleged encounter with alien life in an online discussion with fans last week.
In one post he said: “There may be aliens in our Milky Way galaxy, and there are billions of other galaxies. The probability is almost certain that there is life somewhere in space.
“It was not that remarkable, that special, that unusual, that life here on earth evolved gradually, slowly, to where we are today.”
On July 21, 1969, Neil Armstrong made history by becoming the first person to set foot on the earth’s moon.
Upon landing, he is famously quoted as saying: “That’s one small step for man, one giant leap for mankind.”
Aldrin was on the same mission, Apollo 11, as Neil Armstrong and soon followed in his footsteps – making him the second man on the moon.
Armstrong and Aldrin were on the lunar surface for only 21 hours, 36 minutes and 21 seconds.
