In this image provided by NASA the space shuttle Discovery is seen from the International Space Station as the two orbital spacecraft accomplish their relative separation on March 7, 2011 after an aggregate of 12 astronauts and cosmonauts worked together for over a week. The area below is the southwestern coast of Morocco in the northern Atlantic. During a post undocking fly-around, the crew members aboard the two spacecraft collected a series of photos of each other's vehicle.  Discovery ended its nearly 27-year flying career when it landed Wednesday. (AP Photo/NASA)

In this image provided by NASA the space shuttle Discovery is seen from the International Space Station as the two orbital spacecraft accomplish their relative separation on March 7, 2011 after an aggregate of 12 astronauts and cosmonauts worked together for over a week. The area below is the southwestern coast of Morocco in the northern Atlantic. During a post undocking fly-around, the crew members aboard the two spacecraft collected a series of photos of each other's vehicle. Discovery ended its nearly 27-year flying career when it landed Wednesday. (AP Photo/NASA)