Weakened by years of wear and recent cable failures, Puerto Rico's Arecibo radio telescope faces demolition. Perched atop a hillside, this astronomy landmark will soon be decommissioned.
Commissioned in 1963, the observatory has endured multiple threats. Hurricane Maria in 2017 knocked it offline for months. In August 2020, an auxiliary cable supporting the 900-ton metal platform snapped, with debris slashing the reflector antenna by 30 meters.
These incidents amplified long-standing concerns over chronic underfunding. Though repairs were contemplated, a second cable from the same tower failed in early November, inflicting more damage and uncertainty.
After reviewing three independent engineering reports, the National Science Foundation (NSF)—the facility's overseer—deemed it too unstable for further repairs. The telescope will be decommissioned.
"Our goal was to find a way to preserve the telescope without putting anyone's safety at risk," said Sean Jones, deputy director of NSF's Mathematical and Physical Sciences Branch. "However, after receiving and reviewing the technical assessments, we have found no way forward that would allow us to do so. And we know that a delay in decision-making puts the entire facility at risk of uncontrolled collapse, unnecessarily endangering people and additional facilities."
NSF has engaged engineers to develop a controlled decommissioning plan, potentially using helicopters or explosives. A final method will be selected soon.
Ralph Gaume, director of NSF's Astronomical Sciences Division, pledged support for affected scientists, helping relocate research projects to other facilities.
Until 2016, Arecibo's 300-meter single-dish reflector was the world's largest. It tracked countless near-Earth asteroids and achieved the first radar imaging of one—asteroid 4769 Castalia—in 1989. SETI researchers used it to scan for signals from extraterrestrial civilizations.
Beyond science, Arecibo starred in films like GoldenEye (1995 James Bond) and Contact (1997), inspired by Carl Sagan's 1985 novel.
