© unknownAstronaut Edwin 'Buzz' Aldrin poses next to the U.S. flag July 20, 1969 on the moon
Did all the manned U.S. lunar landings between July 1969 and December 1972 actually take place or were they hoaxes?

A Canadian book publisher has taken a closer look at images acquired by the Apollo 14 astronauts just before they left the moon 40 years ago.

What Robert Godwin uncovered will probably provide more ammunition for those who doubt a U.S. astronaut ever set foot on Earth's celestial neighbour.

Apollo 11 astronauts Neil Armstrong and Buzz Aldrin are credited with being the first humans to set foot on the moon, on July 20, 1969.

One frequently used argument is that video of the Stars and Stripes planted on lunar soil appears to show the flags blowing in the wind - even though there's no atmosphere on the moon.

Godwin says two frames of film taken from the Apollo 14 lunar lander in February 1971 may lead some people to believe that's true.

In one frame, the American flag is pointed to the right, while in another frame, it's pointing in another direction - to the left.

Godwin, 53, says he was drawn to Apollo 14 after viewing high-resolution images of that landing site which were taken recently by a lunar reconnaissance satellite.

"I've watched every scrap of film, every scrap of video and looked at every single photograph I got from NASA," he told The Canadian Press in an interview from Toronto.

That amounts to about 40,000 still pictures and "many, many hours of film footage" - and all TV footage from Apollo 11 through Apollo 17. (The Apollo 13 mission had to be aborted before the spacecraft reached the moon).

He tried to stitch together a composite picture to show the entire view out the window of "Antares", the Apollo 14 lunar lander, using some photos.

Godwin said one still image was missing - but, fortunately, the astronauts had filmed it with a movie camera from almost exactly the same location.

"So I went to grab the final part of the missing panorama from the 16-millimetre movie and in the process of doing that I realized there was this interesting disparity between frames on the 16-millimetre film," he told The Canadian Press.

"My first reaction was: 'What's going on here? How is it possible that the flag can turn around 120 degrees?'."

Godwin says he also noticed that the shadow of the big antenna that astronauts Alan Shepard and Edgar Mitchell used to communicate with Earth disappeared from one frame to the next.

"That's a pretty big thing to have disappear," said Godwin, who has written or edited more than 100 books and is the founder of Apogee Books.

Godwin says that on further investigation, he discovered that the American flag had also been flipped around on the Apollo 12 mission.

And that's when his concerns about the flapping flag were put to rest.

"In fact, it had happened on Apollo 12, that 55 minutes before liftoff, part of their procedure was to test-fire the thrusters on the lunar module," he said.

"That's basically a pretty big rocket engine - just above where the flag is located - and when they did that, it blew over the antenna that was communicating with the Earth and it rotated the flag about 120 degrees."

The same thing happened with the Apollo 14 thrusters.

Godwin adds that the small rockets were powerful enough to set off a seismometer which was set up about a quarter of a mile away.

Bart Sibrel, a Nashville, Tenn., filmmaker, has remained skeptical about the American boast that they landed men on the moon.

He even documents his arguments in a 2001 video called: "A Funny Thing Happened On The Way To The Moon," which is available on the Internet.

Among other claims, the video wonders how the lunar-bound astronauts could have survived travelling through the dangerous Van Allen radiation belt which circles the Earth.

Sibrel and a camera crew confronted many of the lunar astronauts after they returned to Earth, demanding they admit the landings were faked.

He was punched in the face when he went after Aldrin, but a U.S. judge later dismissed the assault charge against the astronaut.

The conspiracy theorist was contacted twice by The Canadian Press, but did not respond when asked to comment on the Apollo 14 flag images.

But Godwin says he has answers to the questions raised by the non-believers.

He dismisses claims that fans on a movie set were making the flags move, arguing the banners were set in motion by the astronauts who planted them into the lunar surface.

"There's a spring inside that flag (and) when you let go of the pole and stop shaking it, the spring has momentum and the flag itself has momentum," he explained.

"It continues to wobble until that momentum has been dispersed.

"There's no air to stop it from flapping so, in actual fact, the momentum will continue longer in a vacuum than it will in air."

As for passing through the lethal Van Allen belt, Godwin says the astronauts just blasted through at the thinnest point.

"If you were to stay in, it would kill if you stayed inside the belts for a week, but they didn't," he added.

But his strongest argument is that all Apollo missions were tracked by the Jodrell Bank Observatory in England, a privately owned facility - and the Russians.

"If anybody had a vested interest in saying it was faked, you'd think it was them," he said.

"Even the Russians sent letters of congratulations saying: 'Well done'!"

Godwin's current project is New Horizons, a photo book featuring lunar panoramas from the Apollo missions. It will be released in July.