{"id":37236,"date":"2022-10-20T00:00:00","date_gmt":"2022-10-20T00:00:00","guid":{"rendered":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/?post_type=purple_issue&p=37236"},"modified":"2023-03-30T09:04:11","modified_gmt":"2023-03-30T09:04:11","slug":"a-farewell-to-airborne-astronomy","status":"publish","type":"post","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/2022\/10\/20\/a-farewell-to-airborne-astronomy\/","title":{"rendered":"A farewell to airborne astronomy"},"content":{"rendered":"\n
\"\"
SOFIA, a powerful 19-tonne infrared telescope mounted on a specially modified Boeing 747SP, was retired from duty in September 2022 <\/figcaption><\/figure>\n\n

A farewell to airborne astronomy<\/h2>\n\n

Niamh Shaw <\/strong>takes a trip on one of the final flights of the plane carrying the SOFIA observatory<\/p>\n\n

The time is 5:30pm on 8 September 2022 and I\u2019m in the mission briefing room at NASA\u2019s Armstrong Flight Research Center in Palmdale, California. I\u2019m about to board a very special aircraft: the Boeing 747 SOFIA aeroplane, carrying a 2.5-metre infrared telescope operated by NASA and DLR, Germany\u2019s space agency. It is one of SOFIA\u2019s last flights; by the time you read this the programme will have ended. <\/p>\n\n

Inside, the cabin is buzzing with activity. It\u2019s extremely loud, so headsets are essential for communication. I tune in to the flight deck comms channel and hear pilots Spike and Bill, and flight engineer Rick. Spike\u2019s the joker and the three enjoy a few laughs together as they wait for clearance. It\u2019s Spike and Bill\u2019s final SOFIA flight. They\u2019ve been flying together for 24 years, having begun their professional relationship in the US Air Force. <\/p>\n\n

\"\"
Niamh about to take off from the Armstrong Flight Research Centre in California <\/figcaption><\/figure><\/div>\n\n

The Stratospheric Observatory for Infrared Astronomy (SOFIA) was a long time coming, with development of the project beginning back in 1996. SOFIA was originally a commercial Boeing 747SP acquired by Pan Am airlines in 1977, and the aircraft still carries the name \u2018Clipper Lindbergh\u2019 in honour of aviator Charles Lindbergh. Extensive modifications were made when it was acquired by NASA in 2007, and in 2009 its telescope cavity doors were opened in full flight for the first time. In May 2010, SOFIA completed its first in-flight tracking of astronomical targets \u2013 the planet Saturn and the stars Beta Leonis and Beta Orionis \u2013 and in July 2013 it made its first deployment to New Zealand for observations of the southern winter skies.<\/span><\/p>\n\n

Throughout the programme, SOFIA\u2019s 10-hour flights have taken it as high as 45,000 feet, soaring above Earth\u2019s distortive atmosphere and giving it an important advantage over ground-based telescopes. From that height, its infrared view penetrated cosmic clouds of dust and gas, enabling astronomers to study the lifecycle of stars, distant nebulae and galaxies and supermassive black holes residing in galactic centres. It also observed closer to home, analysing the planets, comets and asteroids in our own Solar System. <\/p>\n\n

My journey with SOFIA began a few months previous, when I heard that the NASA programme had just one last deployment to New Zealand to complete. I headed to Christchurch in late July 2022 with the intention of joining operations on the ground, working out of the US Antarctic Program building. Unfortunately, severe weather in July had damaged the aircraft, and it wasn\u2019t able to finish its Southern Hemisphere deployment. In late August, SOFIA returned to California to carry out the remainder of its mission. <\/p>\n\n

\"\"
The science teams analyse the incoming data from the FORCAST infrared instrument<\/figcaption><\/figure><\/div>\n\n
\"\"
Co-pilot Michael \u2018Spike\u2019 Tellier in the cockpit during his last shift on SOFIA<\/figcaption><\/figure><\/div>\n\n
High-flying science <\/strong><\/h5>\n\n

While in New Zealand, I met Margaret Meixner, the director of science operations. \u201cThe southern deployment became an essential part of the SOFIA programme,\u201d she told me, \u201cbecause there are objects that can only be seen from the Southern Hemisphere; objects like the Galactic centre, which are incredibly important to observe.\u201d <\/p>\n\n

Mike Toberman, NASA\u2019s SOFIA project manager, was on every New Zealand deployment. \u201cWe started in 2013,\u201d he says, \u201cand it was to be a short mission. But when the scientists got off the plane, they were ecstatic and said it was like observing from space. We kept extending the duration of the appointments, from six weeks to two months.\u201d <\/p>\n\n

\"\"
SOFIA detected helium hydride, the first type of molecule ever formed in space, in planetary nebula NGC 7027<\/figcaption><\/figure><\/div>\n\n
Equipped for success <\/strong><\/h5>\n\n

There were many bodies involved in SOFIA, with the main actors being NASA and DLR. The 2.5-metre onboard telescope was designed and maintained by the German SOFIA Institute in Stuttgart. This vital instrument observed at mid- and far-infrared wavelengths, which enabled astronomers to see regions of the cosmos that would otherwise be invisible, such as hydride molecules, some of the first molecules to form in the Universe. <\/p>\n\n

\u201cOne of the science highlights of SOFIA, the biggest, probably most noted to the public, is the discovery of water on the sunlit surface of the Moon,\u201d Meixner told me. <\/p>\n\n

\u201cAnother highlight has been observing hydrides from our instrument GREAT [see Infrared instruments, below]. Hydrides possess bright rotational transitions in the far infrared. Measuring them is critical to understanding and really pinning down the processes of astrochemistry.\u201d <\/p>\n\n

\"\"
The specially modified Boeing interior included banks of computers to manage the data gathered during a flight <\/figcaption><\/figure><\/div>\n\n

SOFIA\u2019s scientific achievements would be the envy of any ground-based observatory. It has mapped magnetic fields in objects like the Whirlpool Galaxy and supernova remnant Cassiopeia A. It captured an infrared view of temperature changes on Jupiter and studied the formation of planetary systems around distant stars. It discovered how powerful stellar winds are hindering star formation in the Orion Nebula, revealed that magnetic fields are feeding material into the supermassive black hole in galaxy Cygnus A, and detected evidence of a recent exoplanet collision in a double-star system just 300 lightyears away. In 2011, SOFIA flew 2,900km from its Californian base, over the Pacific Ocean to observe Pluto occulting a distant star, providing information about the pressure, density and temperature of the dwarf planet\u2019s atmosphere. That\u2019s something ground-based observatories could only dream of.<\/span><\/p>\n\n

Up in the air <\/strong><\/h5>\n\n

On board my Palmdale flight, I notice how busy the plane is at each of the console areas as scientists make preparations for the collection of data by the FORCAST instrument, SOFIA\u2019s infrared camera and spectrograph. Callie Crowder, who is managing the telescope, prepares for the telescope door opening, the first big event of the night. Over the course of the flight we will observe edge-on galaxies, the sunlit side of the Moon and the galactic mid-plane. It\u2019s a relentless schedule focused on maximising observation time. <\/p>\n\n

I join the pilots in the cockpit upstairs and notice the mood is a lot more relaxed here. I ask Spike how he feels to be on his last-ever SOFIA flight. He says it\u2019s a privilege to have been a part of the programme, and that the deployments to Christchurch were a particular highlight. \u201cIt felt as if the whole of Christchurch knew whenever SOFIA came to town. People were so welcoming. I was very proud of my job when on deployment there.\u201d <\/p>\n\n

He\u2019s right. In Christchurch, whenever I mentioned the reason behind my visits to any of the locals, they perked up and shared their own SOFIA stories. But this was contrasted with disappointment that the current deployment would be SOFIA\u2019s last. In early August 2022, as I left Christchurch on my way to California to catch my SOFIA flight, two officers at passport control took me to one side. I shouldn\u2019t have worried, because they had just discovered the purpose of my visit and wanted to speak more about SOFIA. There had been a TV news special the night before, highlighting the mission\u2019s cancellation. They asked if there was anything they could do to show support and wanted me to thank NASA and DLR for their visits over the years. <\/p>\n\n

\"\"
Free of Earth\u2019s vaporous atmosphere, SOFIA was able to study stellar feedback from massive stars in the Orion Nebula <\/figcaption><\/figure><\/div>\n\n
\"\"
Jupiter imaged with the FORCAST camera at infrared wavelengths that would be impossible from Earth <\/figcaption><\/figure><\/div>\n\n
\"\"
An abundance map for molecular water at the Moon\u2019s Moretus crater, again using FORCAST <\/figcaption><\/figure><\/div>\n\n

The end of SOFIA was tough news for the science team. NASA\u2019s astrophysics division decadal survey in November 2021 concluded that SOFIA\u2019s science productivity did not justify its $85 million a year operating costs. \u201cWe argued that the survey reached its conclusion based on older information and did not take into account SOFIA\u2019s latest discoveries\u201d, Meixner says. \u201cI offered to provide the steering committee with an update, but was unable to do so.\u201d<\/span><\/p>\n\n

Bernhard Schultz, SOFIA\u2019s deputy director of science mission operations, agrees. \u201cWe put into motion measurable improvements in the last four years. The last two years were crucial, but weren\u2019t taken into consideration.\u201d <\/p>\n\n

By now it\u2019s 3am and some of my fellow educators have disappeared, catching an hour of rest to get them through to the 5:20am landing. I\u2019m not sure how the science teams can stay so focused, but they just keep going. <\/p>\n\n

How does Meixner feel about the future of astronomy without SOFIA\u2019s far-infrared data? \u201cThe data we have gathered with SOFIA complements data gathered by telescopes such as the James Webb Space Telescope,\u201d she says. \u201cBut nothing can currently replace what SOFIA has shown us. The last NASA decadal survey seemed interested in developing a far-infrared or an X-ray probe. That won\u2019t be for 10 years though. The gap in data in the intervening years will be felt.\u201d <\/p>\n\n

\"\"
The Educators and Public Outreach Console displaying live pictures from the telescope as it focuses on the sunlit Moon during Naimh\u2019s flight <\/figcaption><\/figure><\/div>\n\n
\"\"
Niamh (second from right) with fellow passengers, educators Nils Wuechner, Fabian Amann and Safia Quazi and, in brown, pilots Spike Tellier and Bill Becker <\/figcaption><\/figure><\/div>\n\n
A farewell flight <\/strong><\/h5>\n\n

By 5am SOFIA\u2019s telescope door has closed and data collection is complete. We take our seats, buckle up and I tune in to the cockpit comms. Spike chokes up as the plane touches down, and we all share a round of applause in his honour. I step off the plane and onto the runway at Palmsdale at 5:30am, when Spike and Bill appear. We invite them to join us for a group photo. \u201cIt\u2019s the end of an era, guys,\u201d Spike tells us, holding back tears. \u201cEnd of an era.\u201d <\/p>\n\n

Just a few weeks later, on 30 September, SOFIA completed its final flight. In its eight years of operation, it flew over 920 times, generating 60 postgraduate theses, 401 research publications, hosting 1,810 unique authors and co-authors, and involving over 3,000 people from the international research sector. <\/p>\n\n

I asked Meixner and Schultz how they wanted SOFIA to be remembered. \u201cFor its scientific discoveries and how it pushed the field of far-infrared astronomy,\u201d Meixner says. <\/p>\n\n

\u201cNot just as a technological marvel, but also for its unique science,\u201d Schultz adds. \u201cFor being unique. For being amazing.\u201d <\/p>\n\n

<\/div>
\n

Infrared instruments<\/h4>\n\n\n\n

How SOFIA\u2019s on-board instruments equipped the plane to observe the Universe <\/strong><\/p>\n\n\n\n

\"\"
The GREAT far-infrared spectrometer mounted on SOFIA\u2019s 2.5-metre telescope <\/figcaption><\/figure><\/div>\n\n\n\n

SOFIA housed six separate instruments that were swapped out regularly to allow the telescope to collect data at wavelengths ranging from near-, mid- to far-infrared, making it a versatile observatory. <\/p>\n\n\n\n

FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope) <\/strong>
This instrument was in operation on my flight and that evening observed edge-on galaxies, the sunlit side of the Moon and the Galactic mid-plane. It is a dual-channel mid-infrared camera and spectrograph sensitive to the mid-infrared range of 5\u201340\u03bcm. But SOFIA hosted a range of other instruments, depending on what astronomers wanted to observe. <\/p>\n\n\n\n

GREAT (German REceiver for Astronomy at Terahertz Frequencies) <\/strong>
A far-infrared high-resolution multipixel spectrometer that didn\u2019t produce pictures of stars and galaxies, but rather extremely detailed spectra of their atoms and molecules. It was used in the first-ever detection of the helium hydride molecular ion (HeH+) in interstellar space.<\/span><\/p>\n\n\n\n

HAWC+ (High-resolution Airborne Wideband Camera Plus) <\/strong>
A camera and imaging polarimeter that imaged in far-infrared light and was used for observing the early stages of star and planet formation, as well as producing maps of magnetic fields. <\/p>\n\n\n\n

FIFI-LS (Far-Infrared<\/strong> Field-Imaging Line Spectrometer) <\/strong>
A far-infrared spectrometer able to trace the formation of massive stars and peer through cosmic dust to analyse star-forming regions. <\/p>\n\n\n\n

FPI (Focal Plane Imager)<\/strong>
A tracking and high-speed imaging camera used as a fast-frame-rate imaging photometer in the 360\u20131100nm wavelength range. <\/p>\n\n\n\n

EXES (Echelon-Cross-Echelle Spectrograph) <\/strong>
Used to split light into a spectrum, enabling astronomers to study chemicals like hydrogen, water vapour and methane from molecular clouds, planetary atmospheres and protoplanetary discs. <\/p>\n<\/div><\/section>\n\n

What next now that SOFIA is over?<\/h4>\n\n

We spoke to two veterans of the airborne observatory about what happens now <\/strong><\/p>\n\n

\"\"<\/figure><\/div>\n\n
Steven Goldman, staff scientist at the SOFIA observatory <\/strong><\/h5>\n\n

\u201cThere is nothing like SOFIA planned for the near future. With the closeout of SOFIA, astronomers are going to lose the capability to detect important tracers and chemical transitions for at least the next decade. We are also losing our best platform for testing and improving new infrared instruments and technology. Balloon missions like GUSTO and ASTHROS, which are currently in development, will provide new far-infrared data in years to come, but won\u2019t fly nearly as often as SOFIA. Far-infrared astronomers will, however, still have tonnes of data to study from the last eight years of successful SOFIA flights.\u201d <\/p>\n\n

\"\"<\/figure><\/div>\n\n
Christian Fischer, project engineer on SOFIA\u2019s Field-Imaging Far-Infrared Line Spectrometer <\/strong><\/h5>\n\n

\u201cOur focus now shifts from data collection to ensuring that the knowledge we learned about observing far-infrared from the stratosphere is preserved. We need to get all the data from SOFIA in the best possible shape and make sure the astronomers have all the support they need to work with this complex information. There will be some very limited access to far-infrared skies by telescopes on stratospheric balloons, but they are not as reliable as SOFIA. For now, better and more reliable balloons or satellites are needed, but that will take some time.\u201d <\/p>\n\n

\n\n
\"\"<\/figure><\/div>\n\n

Niamh Shaw <\/strong>is a science writer and space communicator, and the author of Dream Big: An Irish Woman\u2019s Space Odyssey<\/em>. <\/p>\n\n

<\/p>\n\n

<\/div>\n\n

Photos: NASA\/JIM ROSS, FLORIAN BEHRENS, NASA\/ESA\/HUBBLE PROCESSING: JUDY SCHMIDT, SOFIA CUTAWAY ILLUSTRATION BY PAUL WOOTTON, CARLOS DURAN\/MPIFR, NASA\/SOFIA\/PABST ET AL, JUPITER: NASA\/SOFIA\/USRA\/FORCAST TEAM\/JAMES DE BUIZER (INFRARED IMAGE)\/ANTHONY WESLEY (VISIBLE LIGHT IMAGE), HONNIBALL ET AL. AND APPLIED COHERENT TECHNOLOGY CORP, CHRISTIAN FISCHER: IRINA SMIRNOVA-PINCHUKOVA<\/p>\n","protected":false},"excerpt":{"rendered":"

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