They are nocturnal, so they don't normally move around a lot during the day. Could it have been injured by being hit? Possibly, and if it is injured, there's not much to do. The best thing you can do for it is let it be. However, not flying doesn't necessarily mean it's hurt; it may have just decided that this new location was also fine after some hopping. It will become more active come nighttime.

Not for sure if it is hurt. So what you said could be case. I've never encountered one before and after research I find them very interesting and was concerned for it. So wanted to make sure it was gonna be ok for the short amount of time it has in adult life. Thank you for your reply

In my family, we call luna and polyphemus moths "floppers." The defense they have evolved is flopping around when they feel threatened. It makes them a pain to release the ones we've raised since when they go into flop mode, they refuse to hang on to anything and being on the ground makes them vulnerable to mammals like chipmunks, squirrels, and mice.

My belief is the flopping is useful if the moth is attacked while high up in a tree. The moth is unable to fly because it has not prepared itself to fly (this takes a few minutes to warm up). So it draws its legs close to its body and flops which causes it to drop through branches and escape from the predator. This defense is not worth much if it was already located near the ground.

So bottom line is the luna was probably NOT injured. You just observed its usual defense mode.