Facing collapse, the famed Arecibo Observatory will be demolished

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The world-famous Arecibo Observatory in Puerto Rico, known for helping scientists peer into deep space and listen for distant radio waves, is set to be decommissioned and demolished after engineers concluded that the facility’s structure is at risk of a collapse. While teams will try to salvage some parts of the observatory, the decommission will bring an end to the popular 57-year-old telescope, which has been featured in numerous films and television shows.

The decision comes after two major cables failed at the facility within the last few months, causing significant damage to the observatory. The National Science Foundation (NSF), which oversees Arecibo, assessed the impact of the cable breaks and found that the facility’s other cables could also fail soon. If some of the remaining cables break, engineers fear that the 900-ton suspended platform above the facility could come crashing down on Arecibo’s iconic 1,000-foot-wide dish. It’s also possible that three surrounding towers, which stand at more than 300 feet tall, could topple over in any direction, potentially hitting the visitor’s center or other important nearby buildings.

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

Arecibo Observatory has been a critical part of the science community for the last half-century, allowing scientists to observe exotic deep-space objects and events, such as pulsars and mysterious bursts of distant radio waves. Arecibo has also been a key tool in the search for asteroids that orbit near Earth, helping astronomers find objects that could potentially pose a threat to the planet. Additionally, scientists with the Search for Extraterrestrial Intelligence (SETI) have used Arecibo to search the sky for deep-space radio transmissions that could potentially come from intelligent worlds. Movie viewers will also recognize Arecibo from its inclusion in films like GoldenEye and Contact.

Damage caused by the failure of the first auxiliary cable in August
Image: UCF

The last few years haven’t been kind to Arecibo, though. 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, punching a hole in the observatory’s giant dish. At the time, the University of Central Florida, which manages Arecibo, halted observations with the telescope and launched an investigation, vowing to do repairs.

While engineers worked to get a replacement auxiliary cable, a second main cable snapped on November 6th, also falling onto the dish. The cable, which was attached to the same tower as the auxiliary cable that failed, caused additional damage to the structure and to nearby cables. Engineers with NSF did a full assessment of the facility after this second cable break and found that the remaining main cables, each weighing about 15,000 pounds, could not be relied upon. Arecibo’s main cables were installed decades ago, while the auxiliary cables were installed in the 1990s. “All of the main cables, all of which are decades old and have been through storms, earthquakes, and constant heavy moisture, may no longer be capable of supporting the load that they were designed [to carry],” Ashley Zauderer, the program director for the Arecibo Observatory at NSF, said during the call. In fact, the loss of just one more cable on one of the surrounding towers could lead to the uncontrolled collapse of the entire observatory.

The Arecibo Observatory seen after the second cable failure
Image: NSF

Reports of an impending collapse surfaced soon after the second cable failure, but it wasn’t clear if the telescope could still be saved. Engineers don’t have a timeframe for when the collapse might happen, but they say that the facility will fall apart soon if no actions are taken — and there isn’t much that can be done to stop a collapse from taking place. “Even attempts of stabilization or testing the cables could result in accelerating the catastrophic failure,” Ralph Gaume, director of NSF’s division of astronomical sciences, said during the call. “Engineers cannot tell us the safety margin of the structure, but they have advised us that the structure will collapse in the near future on its own.”

NSF admits that while the agency was focused on other auxiliary cables slipping out of their sockets, no one had expected the main cable break — despite finding some evidence of weakening in the cable that failed. After the August cable failure, engineering teams began more frequent monitoring of Arecibo, and they noticed that 12 of the cable’s 160 wires had broken on the cable that failed. However, the engineers thought the cable was strong enough to handle these breaks and continue holding. “It was identified as an issue that needed to be addressed,” Zauderer said. “It was just not seen as an immediate threat, and I don’t think anyone understood that clearly the cable had deteriorated.”

Ultimately, NSF plans to take down the 900-ton platform and the giant dish in a controlled way, though the 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 hopes to continue work at the Arecibo Observatory LIDAR facility eventually, as well as the visitor center. There is also an offsite facility on the island of Culebra, which collects data on clouds and rainfall. Analyses and cataloging of data collected by the Arecibo telescope will also continue for the foreseeable future.

Arecibo has been a beacon of opportunity in Puerto Rico, and plenty of scientists who have relied on the observatory over the years have expressed dismay at the idea that the telescope could be lost. While it’s a sad day for NSF, the agency is adamant that this was the best decision for the people who work at the observatory, and they are the most important assets. “I think it’s easy to say that it’s the telescope, but it’s not the telescope that’s the heart and soul [of the observatory], it’s the people,” Zauderer said. “NSF truly prioritized the safety of what is truly the treasure.”


And…2020 claims another victim. How depressing. Although it sounds like this telescope hasn’t been properly maintained for several years now, which is absolutely critical for structures like this. 57 years old or not, this was perfectly avoidable. The golden gate bridge is 87 years old and would have fallen into disrepair a long, long time ago if not properly maintained.

That’s OK. Our forever president will look at the sky with his God sight and let us know what’s going on. Who needs Science.

Real shame about that magnificent observatory, though… First exoplanet discovery, mapping Venus’ surface, pulsars… let’s see what happens to its location.

Maintaining Arecibo would almost be like admitting that the US should be spending money taking care of the rest of Puerto Rico though.

What, tossing paper towel rolls isn’t enough??

You’re correct, but I can only imagine the magnitude of difference in budget available to maintain this dish compared to the Golden Gate Bridge.

this makes me inexplicably sad…

Glad I’m not the only one who felt surprisingly emotional about this news. Perhaps mistakes were made in the maintenance, but honestly it’s really hard to maintain any massive structure in the tropics.

Yeah, like the 925,000 pound ISS is easy to maintain — get a couple of clowns in work clothes to walks up and tighten a bolt. And with a cost of $150 billion for the ISS compared with a $million a year to maintain the Arecibo Observatory.

It’s a completely different set of challenges though. Space/LEO is an extreme environment, but environmental erosion is not a factor that has to be considered in its maintenance. Whereas environmental erosion is the number one factor for any structure in the tropics. And I would not be surprised if the cost of maintenance for Arecibo ended up far higher than what was projected during project planning (and therefore never properly budgeted for).

Also, if your government has spent $150 billion on something, then they’re damn well going to maintain the crap out of that bastard.

The "science-per-dollar" of Arecibo is much better than the ISS. Neither the Shuttle or the ISS were the most cost effective ways of doing the jobs they did – even though the Shuttle was "reusable" it still cost more per launch than traditional capsules, and most of the science done on the ISS could have been done on MIR-like or even Salyut-like stations. The Shuttle and ISS were all about prestige and chest-pounding, so they get the money whereas Arecibo does not.

The "science-per-dollar" of Arecibo is much better than the ISS. Neither the Shuttle or the ISS were the most cost effective ways of doing the jobs they did

You’re right, but that wasn’t the argument that the OP was making. Regardless, Arecibo was designed in the 1960’s with a 30-year lifespan (so I read elsewhere yesterday), which it has superseded by 20 years. It’s situated in an extremely harsh environment, and its design makes it inherently hazardous to effect the type of repairs that it needs now.

I hate to see it go, but people much smarter than me have concluded that that is the only legitimate option.

Apples and oranges. For starters, the ISS isn’t pushing 60 years old, nor has it had to contend with hurricanes or other common environmental factors.

Anyone else Goldeneye?

lol yeah, I did the whole Pointing Leo DiCaprio thing.

One of the world’s premier research instruments has lost the political battle for funds.

Fifty years ago Neil Armstrong took a "small step for man" on the Moon from a Lunar Excursion Module (LEM) built on Long Island, New York. Fifteen were built, all did their job, no one lost. It’s replacement in funding, the five Space Shuttles cost half a $billion each launch — two were destroyed, killing everyone aboard. But some connected Senator got the "research" project and jobs for his State and stole the next LEM funding.

We haven’t been back to the moon in a half century!

I guess someone has to make up for things like the James Webb telescope — so far 13 years late with a budget that so far has gone from $500 million to $10 billion. After all, the NSF budget to maintain the Arecibo observatory is $1 million per year. But some other Senator has clout — jobs for a decade late project to get re-elected.

Maybe if Puerto Rico had senators the Arecibo would have been saved… sadly, PR enjoys taxation without representation, a proper US colony, with its second class citizens and its testimonial whispered voice. From time to time, a presidents travels for a few hours to throw tissues at them Boricuas.

You’re probably right about the Moon being a not-great target for exploration (although you’ll find intriguing arguments for He3 mining or scientific observatories all over the web).

But the whole "space vs. Earth" argument is a false dichotomy. First, because not one penny has ever been spent in space…all that money is spent down here on Earth, where it supports lots of jobs in a peacetime effort that has repaid society with amazing technological progress.

But the honest reality is that there is plenty of money to spend on both endeavors — saving our planet and exploring space — but we’re just not spending it that way. The lion’s share of it goes to military budgets and corporate subsidies instead.

You’re welcome, and in hindsight I hope I didn’t come across as too "well actually"…

Estimated cost to build the facility today: $100 million. Pierce Brosnan net worth: $200 million. This can be fixed, even if the fix is rebuilding much of the facility from scratch. It just needs someone to step up and pay for it.

I wonder if they’ll sell little bits of it as keepsakes, like how they did with the Berlin Wall

Maybe they can fund a replacement somewhere with the proceeds from this one. It’s a pretty famous object/landmark.

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