Official NASA Caption: STS102-E-5363 (18 March 2001) --- The International Space Station (ISS) backdropped against black space was photographed with a digital still camera from the Space Shuttle Discovery on March 18, 2001. It is a standard practice for the shuttle to make a final fly-around of the outpost following unlinking from it. A new crew comprised of cosmonaut Yury V. Usachev and astronauts James S. Voss and Susan J. Helms will spend several months aboard the station.
What are we looking at? Behind the ISS, in the referenced "black space" of the solar system, there is an unidentified object. It is clear where the reflection of the astronaut photographer on the glass - and it appears this 'object' is not a part of this reflection.