Because, as I was perusing images for a less recent blog post about the moon (mostly), I found these:
This was found in the NASA archives.
This was found in the NASA archives, as well.
This was found in the San Diego Air and Space Museum Archive.
This was found in the George Eastman House collection.
You may have to peruse closely, but trust me - the evidence is there.
I'm hoping that if I post enough pictures of Daleks, the Doctor will show up.