Stratospheric Observatory for Infrared Astronomy

SOFIA

SOFIA with the telescope door open in flight.
Organization	NASA / DLR / USRA / DSI
Location	Armstrong Flight Research Center, California
Coordinates	34°55′23″N 117°53′06″W / 34.923°N 117.885°W / 34.923; -117.885Coordinates: 34°55′23″N 117°53′06″W / 34.923°N 117.885°W / 34.923; -117.885
Altitude	ground: 702 m (2,303 ft); airborne: 13.7 km (45,000 ft)
Website	SOFIA Science Center NASA SOFIA DLR SOFIA
Telescopes
SOFIA 2.5 meters (98 inches) Bent Cassegrain with chopping secondary mirror and flat folding tertiary, Nasmyth focus
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SOFIA
SOFIA during flight
Other name(s)	Stratospheric Observatory for Infrared Astronomy
Type	Boeing 747SP-21
Manufacturer	NASA/DLR
Construction number	21441/306
Registration	N747NA
First flight	26 April 2007
Owners and operators	NASA
In service	2010-

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an 80/20 joint project of 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. The DSI (Deutsches SOFIA Institut) manages the German parts of the project which are primarily science and telescope related. SOFIA's telescope saw first light on May 26, 2010. SOFIA is the successor to the Kuiper Airborne Observatory.

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). SOFIA's flight capability allows it to rise above almost all of the water vapor in the Earth's atmosphere, which blocks some infrared wavelengths from reaching the ground. At the aircraft's cruising altitude, 85% of the full infrared range will be available. The aircraft can also travel to almost any point on the Earth's surface, allowing observation from the northern and southern hemispheres.

Once ready for use, observing flights were expected to be flown three or four nights a week. Originally scheduled to be operational for 20 years, in its tentative budget for the fiscal year 2015 NASA announced that unless Germany's aerospace center would contribute significantly more than previously agreed upon, the observatory would be grounded by 2015. The SOFIA Observatory is based at NASA's Armstrong Flight Research Center at Palmdale Regional Airport, California, while the SOFIA Science Center is based out of Ames Research Center, in Mountain View, California.