Dark Shuttle Approaching.

What's that approaching? Astronauts on board the International Space Station first saw it far in the distance. Soon it enlarged to become a dark silhouette . As it came even closer, the silhouette appeared to be a spaceship. Finally, at just past 11 pm ( CST ) last Tuesday, the object, revealed to be the Space Shuttle Endeavour , docked as expected with the Earth-orbiting space station. Pictured above , Endeavour was imaged near Earth's horizon as it approached, where several layers of the Earth's atmosphere were visible. Directly behind the shuttle is the mesosphere , which appears blue. The atmospheric layer that appears white is the stratosphere , while the orange layer is Earth's Troposphere . This shuttle mission , which began with a dramatic night launch and will continue into next week, has many tasks planned . These tasks include the delivery of the Tranquility Module which includes a cupola bay window complex that may allow even better views of spaceships approaching and leaving the space station.