Moon astronaut says we're not alone

Edgar Mitchell, the sixth man to walk on the moon, says aliens been visiting the earth for the past sixty years.

When it comes to outer space, Edgar Mitchell knows what he speaks of.

As part of the Apollo 14 moon mission in 1971 Mitchell and Alan Shepard walked on the lunar surface for a record nine and a half hours.

So when 77 year old Mitchell said on British radio that aliens exist and have been visiting earth in UFOs, people sat up and took notice.

SOUNDBITE: Former Astronaut Edgar Mitchell saying (English):

"I don't know how many or where or how they're doing it but, uh, they've been observing us and here for quite some time and we see these craft all the time."

Mitchell goes further.

He says the famous alleged discovery of a UFO and its dead crew at Roswell in 1947 did happen.

But he says this event, and many more, have been covered up by the United States government.

SOUNDBITE: Former Astronaut Edgar Mitchell saying (English):

"The reason for the denial was, number one: we didn't, they didn't know if these were hostile and could we protect ourselves from 'em. 'Didn't want the Soviets to know. So, they devised to lie about it and cover it up."

His distinguished career as an Apollo astronaut makes Mitchell one of the most credible voices ever to enter the alien debate.

But it will take much more to convince those like Don Berliner, from the Foundation for UFO research.

SOUNDBITE: Don Berliner, Chairman, Foundation for UFO Research, saying (English):

"I am sceptical, yeah, and that won't change until as I say he backs it up with something or somebody else comes along., somebody who is not unknown prior to yesterday, backs up what he's said."

Only 12 men ever walked on the moon, and having one of them add his voice to a controversial alien conspiracy theory is potentially embarrassing for NASA.

The agency will only say that Edgar Mitchell remains a great American, but NASA does not share his views on aliens and UFOs.

Andrew Potter, Reuters