By what acronym is National Aeronautics and Space Administration's telescope carrying aircraft known?

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an 80/20 joint project of National Aeronautics and Space Administration (NASA) and the German Aerospace Center (DLR) to construct and maintain an airborne observatory. NASA awarded the contract for the development of the aircraft, operation of the observatory and management of the American part of the project to the Universities Space Research Association (USRA) in 1996.

SOFIA is based on a Boeing 747SP wide-body aircraft that has been modified to include a large door in the aft fuselage that can be opened in flight to allow a 2.5 m (8.2 ft) diameter reflecting telescope access to the sky. This telescope is designed for infrared astronomy observations in the stratosphere at altitudes of about 12 kilometres (41,000 ft).

The SOFIA telescope is by far the largest telescope ever mounted on a plane and opens a new frontier in astronomical exploration. The telescope can also carry special instruments depending on the mission, making it a versatile tool for scientists.