Shorty a small voice (I think from Ill.) ask me to investigate if the circle could in fact be as noted :

"The other possibility is that there is a stray hair in the satellite lens. "

I checked with ML and he gave me a good contact with NASA. The NASA rep. said no way it was theirs'. He noted the Hubble sat/tele had a flaw but not like your circle. He said check with the Ruskies and provided a name. They said no , that it must be from a cheap Chinese low orbit satellite with a disposable camera from Hong Kong. The Chinese said no but check with Hollywood. Finally I found the right guy and he provided that the Star Trek , Star Wars and even the Lost in Space satellites were better than that. He said without hesitation (those movie guys really know about cameras) that it was from the following satellite from a c grade movie and in fact you were seeing the results of 2 crossed hairs not one.

http://i43.photobucket.com/albums/e373/brettski69/fleshgordonship.jpg