Sky & Telescope - April 2023 - 13

NASA's SOFIA observatory came to an abrupt
end last September, leaving many scientists
despondent and a number of projects unfinished.
T
he Boeing 747 lifted toward the sky, taking off at a hefty
pitch and shoving Jim De Buizer back in his seat. The goal
was to reach 35,000 feet - and fast.
At that altitude, the pilots would ease up on the throttle and
open a 4-meter-wide door in the side of the fuselage. It wasn't a
death wish: They were exposing a 19-ton, 2.5-meter telescope to
the starry sky.
It was May 26, 2010, the first night observing with the world's
largest airborne telescope - otherwise known as the Stratospheric
Observatory for Infrared Astronomy, or SOFIA - and
De Buizer had goosebumps. " You're taking off to get the first
photons for an observatory ever, " De Buizer says. " And that's just
pure adrenaline that whole entire time. "
From the ground, water vapor in our atmosphere blocks most
infrared light. But at its maximum altitude of 45,000 feet, SOFIA
flies above 99% of that water vapor, giving it unique access to
the far-infrared part of the electromagnetic spectrum. Since the
project became fully operational in 2014, it has been the only
telescope that could study celestial objects at these wavelengths.
" It's a one-of-a-kind observatory, " says Alfred Krabbe (University
of Stuttgart, Germany), the director of the German SOFIA
Institute. (SOFIA is a joint mission between NASA and the German
Aerospace Center, or DLR.)
So when De Buizer and his colleagues pointed the telescope
toward Jupiter on that first night, they probed depths of the
planet that had never been seen before. The composite image
(obtained by De Buizer on the ground after only an hour's sleep)
revealed heat that had been trapped since the planet's formation
and was now pouring out through holes in the clouds.
The image exceeded his expectations. And by the time SOFIA
completed its development phase in 2014, he and many other
scientists were looking forward to what they thought would be
a 20-year run, giving an unprecedented view of the infrared sky
- a part of the spectrum rich with information about planets,
newborn stars, and galaxies.
THE KEYHOLE This composite image shows
magnetic fields (swirling lines) detected by SOFIA
in the Keyhole Nebula, part of the larger Carina
Nebula, or NGC 3372. The magnetic fields have
the same orientation to those in the larger cloud
complex except in the big loop structure at center,
where the field aligns with the direction of Eta Car's
powerful winds. The alignment confirms that stellar
feedback can disturb magnetic fields in star-forming
clouds, and that Eta Car likely made the loop structure.
The background image is from the European
Southern Observatory's 3.6-meter telescope on La
Silla. The inset by astrophotographer Steve Mazlin
gives a clearer sense of the nebula, taken using
hydrogen-alpha (red) and O III (blue) filters, with a
green channel synthesized from the other two.
sk yand tele scope .o r g * APRIL 2023 13
SOFIA: NASA / SOFIA SCIENCE TEAM / Y. SEO / ESO; INSET: STEVE MAZLIN / SSRO / PROMPT / CTIO

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Sky & Telescope - April 2023

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