NASA Retires 747 SOFIA Airborne Observatory

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Before there was a James Webb Space Telescope, there was a SOFIA—Stratospheric Observatory For Infrared Astronomy. This ambitious project, launched in 2010, consisted of a 2.5 meter infrared telescope mounted in the back of a repurposed Boeing 747SP. SOFIA flew its last mission in September 2022 and last week, NASA flew the aircraft to Arizona, where it will be on display at the Pima Air & Space Museum in Tucson.

As explained in this video shot by Paul Bertorelli in 2013, SOFIA made landmark discoveries in the field of infrared astronomy. Flying above a significant portion of the atmosphere in dry conditions, SOFIA’s telescope could be trained on distant objects with a complex tracking mechanism shown in the video. Among the project’s discoveries were cosmic bubbles and the first ever detection of helium hydride. The observatory also trained its lens on closer object including Venus, comets, Pluto and the moon.

One of the most impressive physical aspects of the aircraft is that its massive pressure bulkhead had to be moved forward and equipped with a special through bearing that kept the telescope properly oriented. Because it has to be kept cold and can’t be enclosed, NASA engineers had to figure out how to design and build a massive exterior door outside the pressure vessel and to channel air around the opening to avoid turbulence and cavitation. The video report explains how this was achieved.  

7 COMMENTS

  1. Dr. Becklin’s desk, shown in much of the second half of the video, is a real throwback to the past. There is so much less paper now that the desk and paperwork seem strange. I can remember when my desk was similarly loaded, but everything was in logical stacks, or at least piles.

  2. I had the great honor of being able to photograph SOFIA in 2006 at L-3 Communications in Waco, TX. The telescope was a marvel of technology which produced astounding results in its time. Sorry to see her 11-year mission end, but the baton has been passed to a far more capable instrument – the James Webb Space Telescope.

  3. Four thirsty engines and the need to be woke and virtue signal score another progressive hit. Sounds like there might be a repurposed use for the telescope but probably will not happen. Has anyone considered re-engining 747s with fewer more powerful and efficient engines such as are used on B 777s and 787s?

    • Boeing and GE used a modified 747 as a flying testbed for the GE-90 engine used on the 777. The engine was mounted on the inboard pylon on the left wing. It definitely looked unusual with the three normal 747 engines that were dwarfed by the -90. According to what I was told, two of the -90 engines could have replaced the four smaller engines, but Boeing had already decided on the 777 platform to eventually replace the 747. In order to convert the 747 to a two-engine design would have required redesigning the original wing to position the engine pylon between the two engines.