NASA stops operations with SOFIA Boeing 747SP

In a statement made on 29 April 2022, the NASA and the German Center for Aviation and Astronautics (DLR) published the decision to close the Stratospheric Observatory project (SOFIA, Stratospheric Observatory for Infrared Astronomy). The operation will be completed by 30 September 2022.

SOFIA is a joint project of NASA and DLR (it owns 20% of the telescope’s working time). The observatory is Boeing 747SP-21 aircraft, registration N747NA (msn 21441/306) on board of which there is a 2.5-meter reflector telescope designed for observations in the infrared part of the spectrum. The working altitude of its flight is 13 – 14 km. This is higher than the bulk of water vapor in the earth’s atmosphere, absorbing infrared radiation. Due to this, about 85% of this spectral range is available to the observatory.

The observatory first took to the air in 2010. During its work, it has completed many studies. NASA has been considering stopping SOFIA for the past few years, mainly due to its high operating costs. The agency spent about USD 85 million a year to maintain the observatory.

The Boeing 747SP-21 is operated by the Armstrong Flight Research Center at Palmdale (CA). The mini-Jumbo was originally delivered as N536PA to PanAm in May 1977. In Feburary 1986 it moved to United to fly as N145UA and was eventually phased-out in July 1995. Two years later the aircraft was acquired by the NASA and operated as N145UA until 2005 when it got its current registration.

Photo by Erik Sleutelberg (Scramble Archive)