Cities at night from space: photographed by NASA astronauts on the International Space Station

London at night

Astronauts aboard the International Space Station are treated to a spectacular view of cities on Earth lit up at night. But the relative speed of the space station meant any photos taken at night were blurred. In late 2002 and early 2003, however, astronaut Don Pettit, part of Expedition 6, constructed a device called a barn-door tracker using spare parts from around the space station. This moves the camera to compensate for the movement of the Space Station relative to the Earth below, resulting in clearer images.