One look at the image of this carving on a cathedral in Salamanca Spain, Catedral Nueva (Built 16th century) would make anyone do a double take:

You can easily see how closely this resembles a modern American astronaut. Complete with helmet, air tubes, backpack and moon boots.
There is no doubt- that is an astronaut.

Well, that is because that is what it represents. It was part of a modern motif done during restoration work in 1992.
I find it very interesting how many books, like Chariots of the Gods, promote such imagery claiming a "mystery" as to its origin while neglecting details such as the above. Is it because of sales profits? Or a psychological need to convince others of the fantastic?