The Stratospheric Observatory for Infrared Astronomy (SOFIA), a modified Boeing 747SP, is a joint project of the US Space Agency, NASA, and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). It is normally stationed at NASA’s Armstrong Flight Research Center in California, but on Saturday, 28 June 2014, it landed at Hamburg Airport.
Extensive maintenance at Lufthansa Technik
From now until the beginning of November, both the aircraft and its telescope will be undergoing extensive maintenance at the Hamburg facilities of Lufthansa Technik. DLR and NASA have selected Lufthansa Technik for the overhaul of the aircraft because they have the world’s longest and most extensive experience with maintaining aircraft of this type.
For Lufthansa Technik, this task is somewhat unusual: “Because SOFIA is not a commercial airliner, but an airborne observatory, there are special operations involved, as well as routine procedures,” says Sven Hatje, the Project Manager responsible for the SOFIA overhaul programme. In five phases – arrival, inspection, modification, installation and acceptance – the engineers will place SOFIA ‘under the microscope’ over the coming months.
Very special Boeing 747
There were 45 Boeing 747SPs built, 18 of which are still in use. Boeing itself, however, no longer supports this aircraft type.The previous US operators of this aircraft, Pan Am, who brought the aircraft into service as ‘Clipper Lindbergh’ in 1977, and United Airlines, who purchased the plane in 1986, also no longer perform maintenance on this type of aircraft, The 747SP – ‘SP’ stands for ‘Special Performance’ – has a much shorter fuselage but the same power; these aircraft can therefore fly significantly higher than other versions, at altitudes of up to between 12 and 14 kilometres.
How stars are formed
SOFIA is a globally unique airborne observatory, which, since 2010, has made around 90 scientific flights to study, among other things, the development of galaxies and how stars and planetary systems are formed from molecular and dust clouds. Installed in the fuselage is a 17-ton telescope, developed in Germany and commissioned by the DLR Space Administration, with a mirror diameter of 2.7 metres. A total of six scientific instruments are currently in use, including the GREAT spectrometer and FIFI-LS, which are operated by German scientists. As SOFIA flies in the stratosphere, above the water vapour in the atmosphere, it can observe infrared radiation with virtually no losses. Ground-based telescopes are not able to measure this radiation from space, as the water vapour blocks most of the infrared radiation..
100 flights per year
After the overhaul here in Hamburg, SOFIA will be resuming operations in 2015 with approximately 100 planned observation flights per year for many years to come and it will continue to be a unique scientific tool for infrared astronomers. him
source and further details:
German Aerospace Center (DLR)