Shocking photographs document the collapse of the Arecibo telescope

The iconic radio telescope of the Arecibo Observatory in Puerto Rico has collapsed, leaving astronomers and the Puerto Rican scientific community to mourn its passing.

Engineers had warned that the 900-ton platform suspended above the telescope’s 305-meter-wide dish could fall at any moment, as one of the main cables supporting it had snapped in early November. Last month, the observatory’s National Science Foundation (NSF) announced it would shut down the telescope permanently, citing safety concerns over its instability and too extensive damage to repair.

The final collapse occurred just before 8am local time on December 1. No one was injured, although the telescope’s director of operations, Ángel Vázquez, was near the control room at the time of the accident, cleaning up valuables in anticipation of another cable failure.

In an interview posted on social media by scientist Wilbert Andrés Ruperto, Vázquez described hearing a loud bang and watching the platform detach from one of the three towers that supported it, then fall and crash into one side of the telescope’s dish. The whole process took about 30 seconds, he said.

NSF said the tops of all three towers have shut down. The images show substantially shorter towers after the collapse than before.

Some nearby buildings, including the control room and visitor center, survived the collapse. One education center, however, appears to have been substantially damaged by the fall of the platform and cables.

Doubts remain about the correct maintenance of the cables over the years. The cable that broke in November, causing the final collapse, dates back to the construction of the observatory in 1963.

Once the largest single-dish radio telescope in the world, the Arecibo facility has been the site of many key astronomical discoveries over the years, including observations of the rotating stars known as pulsars that led to the Nobel Prize in Physics in 1993. Prior to its collapse, astronomers were using the telescope for a number of scientific studies, including radar assessments of near-Earth asteroids, to measure their threat to the planet.

“Our hearts are heavy with this,” Thomas Zurbuchen, NASA’s associate administrator for science, said at a December 1 NASA advisory meeting.

The NSF says it will continue to pay staff at the observatory and continue with the science at other smaller facilities on site that don’t involve the 305-meter antenna. It is unclear whether the plate will be demolished, rebuilt or left in ruins as it is. Observatory director Francisco Córdova told reporters officials would investigate ways to establish similar or even better scientific capabilities, perhaps at or near the site. This, however, would be due to the US Congress allocating funds to replace the Arecibo plate.