The space shuttle Endeavour (top) is seen with the International Space Station in the foreground and the earth in the background after the undocking of the two spacecraft in this image from NASA TV May 30, 2011. [Photo/Agencies]

The space shuttle Endeavour is seen with the International Space Station in the foreground after the undocking of the two spacecraft in this image from NASA TV May 30, 2011. [Photo/Agencies]