A NASA Boeing 747 SP aircraft modified to carry a 2.5-m reflector built by the German Aerospace Center, DLR. It began operation in 2010. SOFIA flies at altitudes of about 13 km to make infrared observations at wavelengths from 0.3 to 1600 μm. SOFIA is based at NASA’s Armstrong Flight Research Center in Palmdale, California, and is operated jointly by NASA and DLR.
http://www.sofia.usra.edu/ Official telescope website.