Astronomers want “strong finish” for SOFIA

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PASADENA, Calif. — The organization that operates an airborne astronomical observatory that NASA is shutting down this year wants to end the project on a high note.

In a June 15 statement, the Universities Space Research Association (USRA) acknowledged the impending end of the Stratospheric Observatory for Infrared Astronomy (SOFIA), a Boeing 747 with a 2.7-meter infrared telescope mounted in its fuselage. NASA announced April 28 an agreement with its partner on SOFIA, the German space agency DLR, to cease flight operations of SOFIA at the end of September. That announcement came a month after NASA’s fiscal year 2023 budget request proposed ending the project.

USRA had in the past opposed efforts to terminate SOFIA, including proposals in the fiscal years 2021 and 2022 budgets. In both cases, Congress restored funding. However, in the statement, USRA said it would work with NASA to wind down SOFIA.

“USRA has been proud to work with NASA on SOFIA whose legacy has been remarkable,” it said. “USRA looks forward to partner with NASA to ensure the safe fly out of SOFIA and ensure that its science legacy is captured appropriately for the astronomical community.”

Project officials offered a similar message at a town hall meeting June 15 during the 240th Meeting of the American Astronomical Society here. They said SOFIA flights would continue to the end of September, including a deployment to New Zealand later this month for southern hemisphere observations.

“The focus on the project right now remains on current operations. Safe operations is our highest priority,” said Naseem Rangwala, NASA project scientist for SOFIA. “Our focus is also on maximizing science observations before the end of this mission. Our goal is to give the SOFIA mission and team a very strong finish.”

That includes, she said, additional flights after SOFIA returns from New Zealand later this summer. That would allow SOFIA to complete up to 80% of its high-priority observations by the end of September.

Rangwala said the project is still working on detailed planning for closeout of SOFIA. Those plans cover placing data into archives, transitioning the project workforce and transferring the instruments and even the aircraft and telescope. “Our desire is for it to be in a museum with the telescope on it,” she said of the aircraft, “but we are working on that.”

There was, though, some frustration among astronomers in the standing-room-only session about the end of SOFIA. A few called on their colleagues to write to Congress in a last-ditch effort to stave off termination.

Paul Hertz, NASA director of astrophysics, said at the town hall meeting that NASA was following the recommendation of the decadal survey published last November, which concluded SOFIA’s modest scientific productivity did not justify its high operations cost: at $85 million a year, only Hubble is currently more expensive to operate among current astrophysics missions. “NASA and DLR have together accepted that recommendation, thus, this is the last year of operations,” he said.

Astronomers at the meeting worried that ending SOFIA creates a gap in observations in the far infrared, at wavelengths longer than even JWST can observe.

“Although we all wish that we could have capabilities in every wavelength all the time, that has just never been true historically,” Hertz said. It’s not the end of mid- and far-infrared astronomy, he said, because of smaller missions. NASA will also consider proposals for larger far-infrared space observatories next year for its first probe-class astrophysics mission.

Advocates for SOFIA have argued the decadal survey did not incorporate increased scientific productivity by SOFIA in recent years when it made its recommendation to terminate operations. Rangwala said the decadal used the number of papers in peer-reviewed publications as its metric of scientific productivity.

“We are ending on a scientific and performance peak,” said Margaret Meixner, SOFIA science mission operations director at USRA, at the town hall meeting. “It’s personally sad to see it closing right at that moment.”