Flying The Flag

This picture and other filmed footage of  the American flag on the moon seems to show it fluttering.  How is this possible if there's no atmosphere or wind on the moon?

This is one of the most common questions about the Apollo landings and is often used as evidence of a hoax.  Fortunately there is nothing peculiar about what we can see here at all.  Not if we remember this is happening on the moon.

• Firstly the flag had a horizontal bar attached to it at the top.  This was done so that the flag would stand out from the flagpole.  NASA appreciated that there would be no wind on the moon, so any normal flag would just hang limply and unattractively down the pole.   To make things look better they added a bar that stood out at 90 degrees from the pole.  The flag was really hanging from this, rather than from the pole.  The bar was also not quite the full width of the flag, so that it was slightly furled to give a 'wave look' to it.

• The moon's surface, once you get past the thin layer of dust, is very hard.  So getting the flagpole to stick in was a tough job.  The footage shows the astronaut twisting the pole back and forth in order to try and get it further into the ground.    This movement made the attached bar and flag flutter.

• The flagpole itself was light aluminium that is quite springy.  Even once the astronaut let go the pole would continue to vibrate.  This in turn would shake the bar and flap the flag.  Without any air to dampen this it would continue to do so for longer than you might expect.

This official NASA website explains the making of the flags taken to the moon.