One of the world’s most iconic astronomical observatories has fallen apart beyond repair. Now it threatens to collapse entirely.
Following two unexpected cable breaks, engineers have determined that the Arecibo Observatory’s 1,000-foot (305-meter) radio telescope is so structurally unsound that any workers who try to fix it would risk their lives. So the National Science Foundation, which owns the Puerto Rico telescope, has decided to decommission it.
Now engineers are racing to figure out how to safely deconstruct one of the world’s largest radio telescopes before it collapses on itself. The structure is so unstable that engineers can’t even approach it to evaluate the risk and timing of such a collapse.
“Even attempts at stabilization or testing the cables could result in accelerating the catastrophic failure,” Ralph Gaume, director of the NSF’s Division of Astronomical Sciences, said in a press conference Thursday morning.
‘It’s like losing someone important in your life’
In its 57-year lifetime, the Arecibo telescope has hunted for hazardous near-Earth asteroids, searched for signs of alien life, and discovered the first planet beyond our solar system. In 1974, Arecibo beamed out the most powerful broadcast Earth has ever sent to communicate with potential aliens. In 2016, it detected the first repeating fast radio bursts — mysterious space signals that scientists now think come from dead stars.
But Arecibo’s woes began in August, shortly after Tropical Storm Isaias passed over the island. A 3-inch-thick auxiliary cable popped out of its socket on one of the telescope’s three towers and crashed into the reflector dish below. It tore a 100-foot gash in the panels.
Then in early November, just before repairs were set to begin in earnest, a 15,000-pound main cable from the same tower broke and crashed into the dish. Engineers had thought the structure was still strong enough to avoid a second disaster — and this cable was carrying just 60% of its estimated load capacity — but the failure proved them wrong. They decided they could no longer trust any of the remaining cables.
Both failed cables had been supporting an enormous metal platform hanging over the dish. If another cable from the same tower were to fail, engineers found, the platform would fall with it.
“The entire 900-ton platform will come crashing down into the main disk, and it’s possible that the three main towers themselves, which are over 300 feet tall, will topple,” Gaume said.
Deconstructing the telescope means abandoning any chance of saving it, but it’s the course of action three engineering firms recommended.
“This decision is not an easy one for NSF to make. But safety of people is our number one priority,” Sean Jones, assistant director for the NSF’s Mathematical and Physical Sciences Directorate, said.
By moving quickly, the NSF hopes to salvage a set of buildings that lay directly below one of the telescope’s towers. That way, the Arecibo Observatory can stay open — but without its defining feature.
“When I learned of the news, I was totally devastated,” Abel Mendez, director of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, told Business Insider. He has been around the observatory since he was 10 years old and worked with it professionally for the last decade.
“It’s hard to take. It’s like losing someone important in your life. Yeah, 2020 — it’s not good,” he said.