Nasa SOFIA project on a modified Boeing B747SP

NASA has recently launched SOFIA — The Stratospheric Observatory for Infrared Astronomy — which lives onboard a modified Boeing 747. At $500 million, the former commercial Pan Am passenger airliner comes with a 17-ton telescope, an oversized window in the fuselage, and a cabin full of instruments carefully studying the view.
SOFIA is the world’s largest airborne observatory.

Read more: http://www.sofia.usra.edu/