This story was updated November 16 with new details and images.
For Arecibo Observatory, things have gone from bad to worse.
On the evening of November 6, one of the telescope’s main support cables broke — the second cable failure in the span of three months. The cable ran from the observatory’s southeast supporting tower and helped to support the 900-ton receiving platform, which hangs over the 1,000-foot (300 meters) reflector dish.
No one was hurt in the accident, according to a November 8
press release from the University of Central Florida, which co-manages the Puerto Rican observatory. But the famed facility now faces the deepest crisis in its 60-year history.
The
first failure on August 10 was of an auxiliary cable, which came out of its socket on the southeast support tower and tore a 100-foot (30.5 m) gash in the dish below. But the line that failed last week was a main support cable. Now, an even greater load on the other cables leaves the platform in a precarious state — and at risk of completely collapsing.
According to a November 13 update released by UCF, based on its design capacity, that cable should easily have borne the additional load in the wake of the first cable failure. That has led engineers to suspect the main cable has degraded over time.
Engineers have not been able to verify the integrity of the two remaining main cables. Worryingly, they have observed signs of fraying in the form of breaks in some of the individual wires making up the cables. “The situation is dynamic and poses a serious safety risk to employees and contractors,” UCF said.
“Given that it seems that the new cable break was from the same tower as the previous one, we are obviously really worried about cascading catastrophic failure,” says Scott Ransom, an astronomer at the National Radio Astronomy Observatory and member of the
NANOGrav (North American Nanohertz Observatory for Gravitational Waves), project, which uses Arecibo data.