NASA's SOFIA aircraft just took to the skies for the very last time

NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft has flown for the very last time.

As per flight tracking website Flightaware, SOFIA's final flight took off on Wednesday, September 28 at 08:44 p.m. PDT (03:44 UTC) from Palmdale, California, and flew for a total of seven hours and 57 minutes before landing back where it took off at 04:41 a.m. PDT the following day.

NASA's SOFIA aircraft flies for the last time

During SOFIA's flights, at the side of the modified Boeing 747 aircraft, an infrared telescope peered out of a hole at altitudes of 42,000 ft (12,800 m) up in the stratosphere. The aircraft flies above 99.9 percent of the atmosphere's water vapor at this altitude, which would otherwise interfere with its infrared observations.

For the past eight years, the flying telescope has taken off with groups of astronomers aboard on round trips that last hours at a time, and it has racked up numerous air miles in the name of science. After today's flight, SOFIA will no longer take to the skies.

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— Thomas Zurbuchen (@Dr_ThomasZ) ) September 29, 2022

In a tweet following SOFIA's final take-off, NASA Associate Administrator wrote, "the SOFIA telescope just embarked on its last flight. On behalf of our team, I am grateful to the dedicated scientists and engineers, including many from [Germany's DLR], who have contributed important science results and have done so safely."

Why is NASA's SOFIA aircraft grounded?

The reason SOFIA is now officially grounded is that NASA decided to stop operating the flying observatory on the recommendation of the Astronomy 2020 decadal survey in November 2021. That survey argued that SOFIA's "science productivity does not justify its operating costs." The observatory's annual operating cost is roughly $85, meaning only Hubble cost took up a significant chunk of NASA's annual budget.

The U.S. space agency also has a very high-profile observatory in a better position to conduct scientific investigations in the infrared spectrum. When it announced it would conclude the SOFIA mission, NASA wrote it "will continue to advance the future of scientific discovery in infrared astrophysics, starting with the recently launched James Webb Space Telescope."

SOFIA leaves behind a stunning scientific legacy

All of that is not to say the SOFIA project hasn't left behind an impressive and fascinating scientific legacy. According to Astrobites.org, the flying observatory is responsible for imaging the first molecule in the universe and several other discoveries, including the detection of carbon on a nearby asteroid.

SOFIA's greatest discovery arguably came on October 26, 2020, when NASA announced it had discovered water on the sunward-facing surface of the moon. Specifically, the water molecules were detected in at the Clavius crater in the southern hemisphere. This was particularly important given NASA's plans to establish a permanent presence on the moon with its Artemis program — the space agency now had a target for mining water.

It might be grounded, but SOFIA's scientific legacy will live on through countless other infrared observation projects carried out by NASA and other organizations in the coming months and years. It could also go down as the project that made it possible for astronauts to live for long periods on the lunar surface.