Friedman ran up a small hill near his home and confirmed his suspicions: A cloud of dust hung in the air where the structure once stood, demolishing hopes held by some scientists that the telescope could somehow be repaired.

“It’s a huge loss,” said Carmen Pantoja, an astronomer and professor at the University of Puerto Rico who used the telescope for her doctorate. “It was a chapter of my life.”

Scientists worldwide had been petitioning U.S. officials and others to reverse the NSF’s decision to close the observatory. The NSF said at the time that it intended to eventually reopen the visitor center and restore operations at the observatory’s remaining assets, including its two LIDAR facilities used for upper atmospheric and ionospheric research, including analyzing cloud cover and precipitation data.