My original tumblr post was here. This image is the cover of a paperback novel Starfire by Robert Buckner, and contains the caption “The hilarious exploits of a bashful scientist and a creature gorgeous enough to send any man into orbit.” The image appears to have first been posted on tumblr by Raiders of the Lost Tumblr who in turn attributes it to this tumblr. It was in turn reposted by makinglovebanana who added the comment “That’s one surprised looking astronaut.” It comes to us promixately by other-whimsey.