Since the United States landed on the Moon on July 20th 1969, there has been an American flag standing on its surface. While 5 out of the 6 flags still stand (Neil Armstrong reported that Apollo 11′s flag was knocked over by engine thrust), the colors of Old Glory have faded due to the Suns harsh radiation.
“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,” LROC principal investigator Mark Robinson wrote. “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!”
On the surface of Earth, even with our protective atmosphere, flags flown in bright sunlight for 44 years will fade severely. The Moon doesn’t have any protection or shade so the flags on it’s surface would have been exposed to glaring sunlight since they were planted. They are also bombarded by the Suns radiation due to not having any protection.
“Over the course of the Apollo program, our astronauts deployed six American flags on the Moon. For forty-odd years, the flags have been exposed to the full fury of the Moon’s environment – alternating 14 days of searing sunlight and 100° C heat with 14 days of numbing-cold -150° C darkness. But even more damaging is the intense ultraviolet (UV) radiation from the pure unfiltered sunlight on the cloth from which the Apollo flags were made. Even on Earth, the colors of a cloth flag flown in bright sunlight for many years will eventually fade and need to be replaced. So it is likely that these symbols of American achievement have been rendered blank, bleached white by the UV radiation of unfiltered sunlight on the lunar surface. Some of them may even have begun to physically disintegrate under the intense flux.”