New report reveals cause of 2020 Arecibo Observatory collapse

The Committee’s findings indicate that, although the fasteners had held up for decades, external forces like hurricanes exacerbated the issue.

Four years after the collapse of the iconic Arecibo Observatory’s radio telescope, the National Academies of Sciences, Engineering, and Medicine has released a report detailing the causes behind the failure, shedding light on both the mechanical and environmental contributing factors.

On Dec. 1, 2020, Puerto Rico and the scientific community mourned that after over six decades of pioneering contributions to space research, the telescope’s story ended in disaster when several cables supporting its 305-meter dish gave way, causing the entire structure to collapse. 

According to the report, the primary cause was an accelerated and unprecedented deterioration of the zinc used to mold the cable fasteners. These fasteners were crucial in suspending the heavy instruments above the dish. Zinc is generally corrosion-resistant and suitable for tropical environments, but in Arecibo’s case, electromagnetic radiation exposure from the telescope’s transmissions led to a process called electroplasticity. This phenomenon, where electrical currents alter a material’s properties, weakened the zinc over time, ultimately compromising the fasteners.

The Committee’s findings indicate that, although the fasteners had held up for decades, external forces like hurricanes exacerbated the issue. After Hurricane Maria in 2017, inspections revealed significant damage to the cables, which continued to degrade over time. Despite the hurricane’s winds not directly damaging the cables, the additional stress accelerated the zinc’s deterioration, leading to eventual structural failure.

The Arecibo telescope was more than just a scientific tool, it was an icon in the field of astronomy. Its achievements included measuring Mercury’s rotational speed in 1967, discovering the first binary pulsar in 1974, and detecting the first exoplanets in 1992. In 1974, it famously broadcasted the “Arecibo Message” to the Messier 13 star cluster, a demonstration of human technological advancement that included information about DNA, human population data, and a map of the solar system.

Though efforts to repair Arecibo failed, the National Science Foundation (NSF) announced in 2023 the development of a new educational facility at the site. Set to open in 2025, the NSF Arecibo Center for Culturally Relevant Science Education, Computational Skills, and Community Engagement will continue Arecibo’s legacy, supporting science education and community engagement in Puerto Rico.

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