Via CBS News, asked and answered:
The flags waving behind are now among the most defining images of our time. But what happened to them is a question University of California Santa Barbara librarian Annie Platoff has been trying to answer.
Her research can account for four of the flags, including the one planted by the Apollo 17 mission. She believes the first two from Apollo 11 and 12 did not survive the ignition gases of the lunar liftoff.
"It wasn't the intention for the flag material itself to last. It was just to be there during the, the event - the landing and departing from the moon. We didn't have a requirement that the flag, the U.S. flag, had to withstand all the environments for eons," Platoff says.
Made from nylon just like the ones at a dime store, though ordered off the shelf from a government supply catalogue, Annie Platoff's theory is they are probably darkened and maybe more than a bit tattered.
Find out more about what happened to the flags, as well as technical difficulties experienced planting them on the moon at CBSNews.com.