Decommissioning of Arecibo Observatory’s 305-meter telescope

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nsaspook

Joined Aug 27, 2009
7,750
https://www.nsf.gov/news/news_summ.jsp?cntn_id=301674
November 19, 2020

Following a review of engineering assessments that found damage to the Arecibo Observatory cannot be stabilized without risk to construction workers and staff at the facility, the U.S. National Science Foundation will begin plans to decommission the 305-meter telescope, which for 57 years has served as a world-class resource for radio astronomy, planetary, solar system and geospace research.

The decision comes after NSF evaluated multiple assessments by independent engineering companies that found the telescope structure is in danger of a catastrophic failure and its cables may no longer be capable of carrying the loads they were designed to support. Furthermore, several assessments stated that any attempts at repairs could put workers in potentially life-threatening danger. Even in the event of repairs going forward, engineers found that the structure would likely present long-term stability issues.

"NSF prioritizes the safety of workers, Arecibo Observatory’s staff and visitors, which makes this decision necessary, although unfortunate," said NSF Director Sethuraman Panchanathan. "For nearly six decades, the Arecibo Observatory has served as a beacon for breakthrough science and what a partnership with a community can look like. While this is a profound change, we will be looking for ways to assist the scientific community and maintain that strong relationship with the people of Puerto Rico."
https://www.imdb.com/search/title/?locations=Arecibo+Observatory,+Arecibo,+Puerto+Rico

 

SamR

Joined Mar 19, 2019
2,809
That's a shame. I wonder if there are any plans to replace or is it considered antiquated technology now...
 

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nsaspook

Joined Aug 27, 2009
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That's a shame. I wonder if there are any plans to replace or is it considered antiquated technology now...
Ships are decommissioned and a new ones commissioned at some future date so I suspect one day a new receiver will be there.
 

SamR

Joined Mar 19, 2019
2,809
I hope it fares better than the Texas Super-Collider did. I wasn't sure if they saw it as they do WWV or LORAN as having served it's purpose for it's time and no need to be replaced.
 

jpanhalt

Joined Jan 18, 2008
10,525
Very sad. If it can be built, why can it not be re-built?

Will we doom Hoover dam to the same future? The Washington monument, even the White House to the same?
 

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nsaspook

Joined Aug 27, 2009
7,750
Very sad. If it can be built, why can it not be re-built?

Will we doom Hoover dam to the same future? The Washington monument, even the White House to the same?

Some of the bad cables. (failed main cable failed at a load of 60% of its expected strength, that's not a good sign) The dish has seen damage from earthquakes and most recently hurricanes, plus obvious accumulated wear and tear from exposure.
https://www.naic.edu/history_gal/historicgal.html

http://www.darkroastedblend.com/2008/07/giant-radio-telescope-collapses-and.html
Sure it can be rebuilt from scratch like Green Bank but is the money well spent on that location?

We have far surpassed the capability of single dish Arecibo with phased array instruments.
 

SamR

Joined Mar 19, 2019
2,809
Any kind of failure like that at its age is indicative of poor maintenance.

EDIT: can you imagine the uproar that would occur if a cable failed on the Brooklyn or San Francisco Bay bridges?!?!
 
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Thread Starter

nsaspook

Joined Aug 27, 2009
7,750
Any kind of failure like that at its age is indicative of poor maintenance.

EDIT: can you imagine the uproar that would occur if a cable failed on the Brooklyn or San Francisco Bay bridges?!?!
If you've ever worked on technical structures in a tropical jungle you can understand why old structures fail prematurely even with the best of maintenance when there are hurricanes and earthquakes that stress components to the breaking point.

 

SamR

Joined Mar 19, 2019
2,809
No experience with earthquakes but working at a 75 year old chemical plant on a seashore hit by several hurricanes and that used acid and chlorine in their processes I do know a bit about corrosion and what preventative maintenance entails.
 

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nsaspook

Joined Aug 27, 2009
7,750
No experience with earthquakes but working at a 75 year old chemical plant on a seashore hit by several hurricanes and that used acid and chlorine in their processes I do know a bit about corrosion and what preventative maintenance entails.
It was a technical instrument (An air-force radar for ionospheric detection of missiles) designed with a limited lifetime sitting exposed on the top of a tropical mountain.
"Though some ARPA scientists saw the scientific value of Arecibo, ARPA's main interest in the project was as part of the Defender Program to track the ion trails created by missile exhaust."
https://ntrs.nasa.gov/api/citations/19960045321/downloads/19960045321.pdf

Mother Nature limited its lifetime IMO, not a maintenance crew.

So we should probably celebrate its relative longevity and cost effectiveness. RIP
 
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andrewmm

Joined Feb 25, 2011
671
One has to remember it was originally part of the cold war infrastructure,
that's why its a radar, radio transmitter as well as a receiver,

No military funding for a long time,
and without that money, its unlikely to be re built.

My bet is the flying structure will be dropped into the hole, probably using explosives, and then it will be just left to rot.

IMHO, very very very sad statement on how things are.
 

SamR

Joined Mar 19, 2019
2,809
Yep, we have several ex-Navy platform towers offshore here in GA that were used by the Glynco Naval Air Base (WWII Blimp Base for submarine detection with the world's largest wooden structures which were blimp hangars) until the base was decommissioned (Now the Federal Law Enforcement Training Center). They stripped the electronics off the platforms and left them to rot. One thing that can be said for mil-spec construction is that they are still standing after over ~80 years now. The wooden hangers however were torn down in the 60s or so.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
7,750
One has to remember it was originally part of the cold war infrastructure,
that's why its a radar, radio transmitter as well as a receiver,

No military funding for a long time,
and without that money, its unlikely to be re built.

My bet is the flying structure will be dropped into the hole, probably using explosives, and then it will be just left to rot.

IMHO, very very very sad statement on how things are.
We have an agreement with PR to clean up the site to near original with costs from $20M to $100M. It's in a RF quiet zone with almost no local development so the wild-life there has been protected since the 60's.
“Partial Deconstruction and Site Restoration” -- Alternative 4 involves the deconstruction of all above-grade structures, except for large, concrete structures; that is the towers, tower and catwalk anchors, and rim wall infrastructure. All below-grade foundations would be stabilized and filled in with reforestation of native species.

"Complete deconstruction and site restoration" returns the site back to jungle but would involve disturbances from explosions and deconstruction activities that might cause wildlife habitat destruction.
From the Arecibo Observatory Final Environmental Impact Statement — NSF
 

WBahn

Joined Mar 31, 2012
26,308
My understanding, which is admittedly superficial, is that Aricebo has been somewhat of a white elephant for some time, it's days of being at the forefront of research usefulness being well in its past. Most of its abilities are now far outstripped by the steerable phased array telescopes. In addition, whatever capabilities are unique to a single large-dish antenna can almost certainly be served better by the FAST observatory in China, which has something like twice its area.

I can't help but think that if they were really motivated to keep the observatory operational that they could find a way to do the necessary work in a safe way. If nothing else, they could erect new towers between the others and use helicopters to connect cables to the structure. But they clearly figure that the potential utility of the facility isn't worth the cost and effort.

I haven't heard what capabilities Arecibo will still have, if any, without the suspended head and whether or not the plans are to reclaim the site altogether or keep it operating with a reduced mission.

Like so many engineering marvels, it has served its purpose well and it is time for it to be relegated to its place in the history books. It's sad and I wish it weren't so, but that's the way it is.
 

Sensacell

Joined Jun 19, 2012
2,634
This is very sad. I visited Aricebo in the early 90's.
It was already evident then that they did not do much in the way of maintenance.
 

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nsaspook

Joined Aug 27, 2009
7,750
It didn't wait for the decom crew to arrive.
https://cosmiclog.com/2020/12/01/collapse-delivers-death-blow-to-arecibo-radio-dish/

The Arecibo radio telescope’s 900-ton instrument platform fell into the 1,000-foot-wide antenna dish this morning, adding to previous damage and putting Puerto Rico’s iconic scientific structure beyond repair.
NSF said preliminary findings from an investigation into the platform’s fall suggest that the top sections of all three support towers snapped off. As the platform made its 500-foot drop to the dish, its support cables also dropped, according to the NSF’s statement.

gettyimages-1229890655-2048x2048.jpg
 
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