Image caption John Young salutes the flag while jumping in this picture taken by Charles Duke on the Apollo 16 mission

Images taken by a Nasa spacecraft show that the American flags planted in the Moon's soil by Apollo astronauts are mostly still standing.

The photos from Lunar Reconaissance Orbiter (LRO) show the flags are still casting shadows - except the one planted during the Apollo 11 mission.

This matches Buzz Aldrin's account of the flag being knocked over by engine exhaust as Apollo 11 lifted off.

LRO was designed to produce the most detailed maps yet of the lunar surface.

Each of the Apollo missions that touched down on the Moon planted an American flag in the soil.

Scientists had previously examined photos of the landing sites for these flags, and had seen what looked like shadows cast by them on the lunar surface. But this was not considered conclusive.

Now, researchers have studied photos of the same areas taken at different points during the day and have observed shadows circling the points where the flags are thought to be.

Prof Mark Robinson, the chief scientist for the spacecraft's camera instrument, LROC, said in a blog entry: "From the LROC images it is now certain that the American flags are still standing and casting shadows at all of the sites, except Apollo 11."

The Arizona State University scientist added: "The most convincing way to see that the flags are still there, is to view a time series of LROC images taken at different times of day, and watch the shadow circle the flag."

"Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did. What they look like is another question (badly faded?)"

LRO began its mission in lunar orbit in September 2009, to identify mineral and other resources on the Moon as well as scout promising landing sites for future missions.