UFO in NASA image moving towards Earth

This very interesting image has surfaced the internet these days. What appears to be a disk shaped object is caught in two separate images moving towards our Planet.
This object has a very defined shape and this time cannot be mistaken for space debris, bad pixels nor camera malfunction.

In one of the images this unidentified object seems to have a central part that stands out from the rest of the spacecraft. The question here is, who does it belong to? Is this a real extraterrestrial craft? Let us know what you think.
Here are the links to the official NASA images:
 http://eol.jsc.nasa.gov/sseop/images/ISD/highres/AS08/AS08-14-2534.JPG
 http://eol.jsc.nasa.gov/sseop/images/ISD/highres/AS08/AS08-14-2532.JPG