New Nasa photographs show most of the flags placed by crews of the Apollo spacecraft are still standing on the Moon.
Shadows cast by five of the six US flags put up in the 1960s and 1970s are visible on the surface of the Moon as it spins around the sun.
The remaining flag - planted by Neil Armstrong and Buzz Aldrin during the first moon landing in 1969 - was knocked over as the Apollo 11 craft began ascending from the surface.
Mark Robinson, an investigator with the Lunar Reconnaissance Orbiter Camera (LROC), said: "From the LROC it is now certain that the American flags are still standing and casting shadows at all of the sites, except Apollo 11.
"Astronaut Buzz Aldrin reported that the flag was blown over by the exhaust from the ascent engine during liftoff of Apollo 11, and it looks like he was correct!
"Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did."
The famous Stars and Stripes may not have retained their vibrant red, white and blue colours though. Exposure to heat, cold and light may have caused them to fade, Dr Robinson added.
Flags were placed by US astronauts on all six Apollo landings between 1969 and 1972.