What? The atmosphere has nothing to do with flags waving for hours. The pole itself would create losses. If you bend something repeatedly it gets warmer as internal friction of the materials change the energy into heat. Unless NASA have created a
perpetual motion machine and plonked it on the moon in 1969.
[/quote]Oh my, you don't understand what a perpetual motion machine would be. First, please learn the definition of "perpetual". Then tell us how long you observed the flag wave, without interruption. Now tell us that you've misused the term.
Next, please study thermodynamics. Since the flag is not a closed system, you can't argue that it must stop waving based on your limited understanding of TD and perpetual motion. Surely uneven heating by the Sun on the flag, for example, could keep the flag waving throughout the photography period of each mission.