Faced with the collapse, the famous Arecibo Observatory will be demolished

The world famous Arecibo Observatory in Puerto Rico, known for helping scientists scan deep space and listen to distant radio waves, will be dismantled and demolished after engineers concluded that the facility’s structure is at risk of collapse. While teams will attempt to salvage parts of the observatory, the decommissioning will put an end to the popular 57-year-old telescope, which has been featured in numerous movies and television shows.

The decision comes after two major cables failed the installation in recent months, causing significant damage to the observatory. The National Science Foundation (NSF), which oversees Arecibo, evaluated the impact of cable breaks and found that the other cables in the facility could also fail soon. If some of the remaining cables break, engineers fear the 900-ton suspended platform above the facility will collapse onto the iconic 1,000-foot-wide Arecibo plate. It’s also possible that three surrounding towers, which are over 300 feet tall, could tip over in any direction, potentially hitting the visitor center or other important nearby buildings.

With this imminent threat in mind, NSF determined that Arecibo cannot be safely repaired without risking human lives. Agency engineers evacuated the facility and established a safety exclusion zone around spaces where people could be in danger if there were a collapse. Meanwhile, engineers are now working on a plan on how to safely dismantle the facility, which could involve the use of helicopters and perhaps even explosive demolitions. “This decision is not an easy one for NSF to make, but people’s safety is our number one priority,” said Sean Jones, NSF assistant director of mathematics and physical sciences, during a call with reporters.

The Arecibo Observatory has been a fundamental part of the scientific community for the past half century, allowing scientists to observe exotic deep space objects and events, such as pulsars and mysterious explosions of distant radio waves. Arecibo has also been a key tool in the search for asteroids orbiting close to Earth, helping astronomers find objects that could potentially pose a threat to the planet. Additionally, Search for Extraterrestrial Intelligence (SETI) scientists have used Arecibo to search the sky for radio transmissions in deep space that could potentially come from intelligent worlds. Movie viewers will also recognize Arecibo for its inclusion in movies like Golden eye Y Contact.

Image: UCF

However, the last few years have not been kind to Arecibo. In 2017, the facility suffered significant damage when Hurricane Maria passed over Puerto Rico, causing up to $ 14.3 million in needed repairs. Then, in August of this year, an auxiliary cable, used to support the floating platform above the telescope, slipped out of its socket and fell, drilling a hole in the observatory’s giant dish. At that time, the University of Central Florida, which runs Arecibo, stopped observations with the telescope and launched an investigation, promising to make repairs.

As engineers worked to obtain a replacement auxiliary cable, a second main cable broke on November 6 and also fell onto the platter. The cable, which was connected to the same tower as the failed auxiliary cable, caused additional damage to the structure and nearby cables. NSF engineers did a full evaluation of the installation after this second cable break and found that the remaining main cables, each weighing approximately 15,000 pounds, could not be trusted. Arecibo’s main cables were installed decades ago, while the auxiliary cables were installed in the 1990s. “It is possible that all the main cables, all of which are decades old and have been through storms, earthquakes and a lot of constant humidity , are no longer capable of supporting the load for which they were designed [to carry]”Ashley Zauderer, director of the Arecibo Observatory program at NSF, said during the call. In fact, the loss of just one more cable in one of the surrounding towers could lead to the uncontrolled collapse of the entire observatory.

Engineers do not have a deadline to determine when the collapse could occur, but they say the facility will collapse soon if action is not taken, and there isn’t much that can be done to prevent a collapse from occurring. “Even attempts to stabilize or test the cables could result in the acceleration of the catastrophic failure,” Ralph Gaume, director of NSF’s division of astronomical sciences, said during the call. “The engineers cannot tell us the safety margin of the structure, but they have informed us that the structure will collapse on its own in the near future.”

NSF admits that while the agency focused on other jumper cables coming out of their sockets, no one expected the main cable to break, despite finding some evidence of weakness in the failed cable. After the August cable failure, engineering teams began monitoring Arecibo more frequently and noted that 12 of the 160 cable cables had broken on the failing cable. However, the engineers thought that the cable was strong enough to withstand these breaks and continue to hold. “It was identified as a problem that needed to be addressed,” Zauderer said. “It just wasn’t seen as an immediate threat, and I don’t think anyone understood that the cable had clearly deteriorated.”

Ultimately, NSF plans to bring down the 900-ton platform and giant plate in a controlled manner, although engineers don’t know exactly how long it will take or how much it will cost. And not all of Arecibo will be a total loss. NSF expects to continue working on the Arecibo Observatory’s LIDAR facilities eventually, as well as the visitor center. There is also an external facility on the island of Culebra, which collects data on clouds and rainfall. Analyzes and cataloging of data collected by the Arecibo telescope will also continue for the foreseeable future.

While it is a sad day for NSF, the agency insists this was the best decision for the people who work at the observatory, and they are the most important assets. “I think it is easy to say that the telescope is, but it is not the telescope that is the heart and soul. [of the observatory]It’s the people, ”Zauderer said. “NSF really prioritized the security of what the treasure really is.”

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