How do astronauts take their wonderful pictures of Earth from space? ESA astronaut Alexander Gerst demonstrates the European-built Cupola observatory on the International Space Station.

Offering a full 360° view of Earth and the Space Station, its main purpose is to observe approaching spacecraft and monitor spacewalks. When the Station’s robotic arm is used to dock spacecraft or move astronauts on a spacewalk, the arm is controlled from a command centre inside Cupola. The observatory is also used for visual scientific research of Earth but naturally offers a place for astronauts to relax and take pictures, the bay windows offer the best panoramic view of our world.

The windows are protected by external shutters, which can be opened by with the simple turn of a button. The shutters are closed when not in use to protect the glass from micrometeoroids and orbital debris, and to prevent solar radiation from heating up Cupola or to avoid losing heat to space.

Each window has three subsections: an inner scratch pane to protect the pressure panes from damage from inside. Two 25 mm-thick pressure panes to maintain cabin pressure (the outer pane is a back-up to the inner pane), and a debris pane on the outside to protect the pressure panes from space debris when the shutters are open.

The Cupola module was launched and installed in February 2010 during Space Shuttle Endeavour mission STS-130.