The AM Forum

https://spacenews.com/nsf-to-decommission-arecibo-radio-telescope/?fbclid=IwAR01gBdA2xMpfMo1e5L1iDM6RnDKhvFYBWu7qN_inxDMLl4G-YgQNpFi5d8

That is a real shame.  :-[

It fall down - go boom  - Lots of scrap metal to sell.

The one in China, now certified and fully operational as of January 2020, is now the largest single dish radio telescope in the world. Its dish diameter is actually 200 meters greater then the one in Arecibo.
https://www.eurekalert.org/pub_releases/2019-09/caos-cse090919.php

I guess James Bond will have to visit this one too  :D

(https://media.eurekalert.org/multimedia_prod/pub/web/210752_web.jpg)

No doubt all the radio gear at Arecibo is spoken for or will be spirited away in some or another manner perhaps by an institution or government. I would love to know what is in use, or what was in use until the disaster. What a shame for the free world to lose that installation. How long until the forest reclaims it?

I have visited the Arecibo dish site twice.  It's very cool, and has an excellent visitor facility with a variety of displays from elementary to rather technical.  When you get there, you have to leave your cell phone off and back in the car to minimize RF smog.  Then you walk up a couple hundred feet of steep road to the main building  The control console room is separated from the visitor area by large glass walls. but you can see all sorts of signal processing stuff in racks, and people doing cool things at the console. 
One of the main feeds at the focal point is a 438 mhz unit but they have, at least on one occasion, fired it up on 432 moonbounce..
As expected, the island atmosphere is very corrosive and cable maintenance obviously wasn't enough.  I'd hate to be the fellow who had to climb out there and replace a thimble.  The new Chinese dish is pretty impressive, but the Arecibo operation was still doing some good science.  It's a shame to lose it.
A few years ago, my Dear Sweetie and I were watching a rerun of 007's Goldeneye on TV.  She was impressed that I had been to such a great nerd spot.  Chicks dig that stuff.
73 de Norm W1ITT

I remember reading about that in some Time/Life Astronomy book in 5th grade. I thought it was awesome the way they used the contour of the land to 'make it fit'! I thought this was also used to communicate to Voyager 1/2 explorers now out in to 'outer space'. Something tells me this asset is too valuable to go to waste and will be hopefully retrofitted. I hate to think that we would be relying on the Chinese to communicate to those satellites!

Mike.. Much of the deep space communication and control uplink with the way far out space probes is done out of a site in Australia, the name of which escapes me.  There's also a big dish in Spain. The advantage of those two sites is that they are steerable over a wide range, as opposed to Arecibo which has minimal moving of the feed.
The "soil" up there at Arecibo is karst, a high calcium material that hard and rough.  The site was originally a fairly good natural dish, but there was additional excavation involved.  The roads up to site are all paved and go past many houses that are right up to the edge of the road but they are twisty and turny.  I can't imagine what the truck drivers had to go through carrying all that equipment and structural material up there.  It's nerve wracking in an automobile.  That vehicle that James Bond had was definitely the better choice.
73 de Norm W1ITT

Imho, something smells bad on this one.

Cables don't suddenly snap, unless nobody is paying attention to their
condition. Note all the suspension bridges in the world? No snapped cables
so far??

No money?
Horsepucky.

They likely could have raised the money with a "GoFundMe" or similar.
Not to mention a reasonable campaign to "entice" the lawmakers who were/are
set to blow up to 3 TRILLION DOLLARS "stimulating" the so-called economy.

Something seems very very off about this...

No more Arecibo?   Are we still going to Mars?    Are we still going to land a woman on the moon by 2024?  Is there still going to be a Space Force?  Will NASA stay funded?

(sigh....)


T

It's not the end. The VLBA has been in operation since 1993 and is still active. It's far more versatile than Aricebo. Thye had used Arecibo in the array (along with a dish in Germany) to increase sensitivity.

How many people even know we have a U. S. Space force:
https://en.wikipedia.org/wiki/United_States_Space_Force

(https://upload.wikimedia.org/wikipedia/commons/c/cf/Space_Force_Delta_Garrisons_Graphic_%28Delta_2%29.jpg)

Women have already been to Mars:

(https://images-na.ssl-images-amazon.com/images/I/51ngIl-ut6L._SY445_.jpg)

BUT WE REALLY NEED TO KNOW - WILL WE HAVE GREAT F2 PROPAGATION IN THIS NEW SUNSPOT CYCLE

Norm said:
Yeah and there was an issue with either the antenna or the receiver that they lost contact for a while with the probes. It was supposed to be a back-up for the Arecibo one if I remember reading the article correctly because they discussed the maintenance on Arecibo prior to this weeks developments.

This is a good read on the history of Voyager 1 and 2. Talks about the spacecraft and comms systems.

https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--141029.pdf

The suspended platform collapsed over night last night. 

Before and after

(https://pbs.twimg.com/media/EoJsJl0XUAI3XfT?format=jpg&name=large)

(https://ichef.bbci.co.uk/news/800/cpsprodpb/0375/production/_115758800_gettyimages-1229890557-1.jpg)

Ouch! That's going to keep your pan fish down for a while!

Here is a 3 minute video of the damage, helicopter view.  Communications is mostly in Spanish.

https://www.youtube.com/watch?v=tkfFuz13dYE&feature=youtu.be

I wonder if part of the dish isn't still usable....??

Thinking like a true ham, Steve!
Happy holidays.

I believe that they were planning to decommission it anyways.

Might only useable for James Bond films now.

(https://cdn.gelestatic.it/businessinsider/it/2020/11/arecibo-goldeneye-2-2-768x325.jpg)

Yeah...a little hammy hambone action.....would be cool..

Video of the collapse.   ooops.

https://www.youtube.com/watch?v=gGGoXRAIwtw (https://www.youtube.com/watch?v=gGGoXRAIwtw)

So that drone just happened to be in  the air during the collapse?  great pictures...the guy taking the pictures must have felt helpless to do anything..

They had been monitoring it continuously from fixed and drone cameras since the initial failure. They were trying to figure out what they might do about stabilizing the whole thing before the inevitable collapse.

Ya know, the first time I saw that newer tower rigging with the suspended steel structure a couple decades ago I got a bad feeling. There is a tremendous load holding up a "house" like that ... like somebody doing an iron cross on the rings.  Probably a better solution would be a huge, single, strapping center tower support, self supporting. The radio dome could be offset from the tower for a clear shot down into the apex.  Just like we see radio telescope offset dishes do now.   What would be lost in aperture would be gained getting rid of all the cables and wires causing array blockage and interference. And, a superior physical structure.

Better yet, take some of that Washington slush money and build a new one out in the  New Mexico or Arizona desert. Modern 2020, first class equipment.   Imagine one the size of the big meteor crater in AZ?  Make it easier for USA scientists to access.

T

I think they knew where the failure point would be and were monitoring it on a regular basis and just edited out any preceding footage. If not, if you look at the failure mode at the attachment points of the cables, at about 0:41 seconds and going forward, I think they knew something was up based on the first cable that snapped. The first cable, prior to snapping, was absent of paint and clean and shiny at that point in time.   Paint is blown off from additional tension or stretching. then on the first cable you can see when one strand snaps more paint comes off then it escalates from there. Then just before the time the other cables snapped they lose paint as well.

The suspension cables that suspend the 900ton platform would have to have precisely equal tension to maintain integrity. If one cable fails or tension drops considerably in one cable suddenly for whatever reason the other cables end up being over stressed.  Almost seems like the design did not have enough redundancy or headroom built in for such a situation.

slow motion video
https://www.youtube.com/watch?v=59WQIRvezzI&feature=youtu.be

Really interesting detail on Arecibo and what happened.

https://www.youtube.com/watch?v=3oBCtTv6yOw (https://www.youtube.com/watch?v=3oBCtTv6yOw)

It appears that there is work going on there now.
I saw a vid of scaffolding put up on a tower.

It may be that they are rebuilding it... dunno.

                    _-_-bear

Here is an article from six days ago ;   Space.com says  it would cost $454 million to rebuild.  The US govt should peel this off from their $Trillion slush fund.

Personally, I would like to see it rebuilt, but with a different design.  Use the same dish but build a strapping center pillar to support the RF secondary dome in the middle.  That cables-supported method was so JS and mechanically a nightmare.   A free-standing tower/pillar in the center with the dome offset with full rotation in 2 axis' would do the job FB and get rid of all cables and side tower supports. The obstruction field filled with cable RF reflection artifacts would be eliminated too.  

T





https://www.space.com/arecibo-telescope-replacement-process-and-designs

The RF dome was slidable in declination as well as a little in hour angle.  It depended on earth's rotation for primary hour angle.  Rotation of the RF dome receivers required for proper R.A. alignment in essentially an alt. / az. mount.

A central column may be just as shadowing and vibration at apex prone as the three dimensional, three point stressed cable array.   -( 3 point stressed catenary structure.)

Interesting that the larger Chinese copy uses six peripheral towers of same design instead of three.

Interferometer Radio telescopes of many smaller antennae spaced on tracks or time sequenced with far larger base lines have pretty much superseded single, large single dishes.  This is the biggest reason that  single dish antennae have lost funding.

The Chinese just have to have the latest/greatest even if the usefulness is limited, in this case to shear single antenna power illumination at a slight increase of resolution compared to the once world's largest.

The large, fully steerable single dish antenna in WVA ( a radio quiet zone, AM included  ;D ) is kept operable pretty much because it is fully steerable and not dependent on earth's rotation for R. A.   Even at that it's future is questionable.    Because of the recent orders of magnitude in time base with even relativity corrected precision, interferometer radio telescopes of planetary orbit Lagrange point distances are now feasible. 
 

Good points, Rick.

Maybe it's time to look ahead to newer technology instead of rebuilding in the 60's.   Get Elon Musk involved to orbit an array of interferometer radio dishes past Earth orbit, into solar orbit, synchronous to the Earth..  Lots of them spaced as far apart as possible.   Aside from maintenance problems, it would be the next logical step in greatly meaningful progress. But what a project in complexity!

T

Yeah, I got a little stuffy there.
 Your right. Instead of sending up perfectly good Teslas, a better choice would’ve been at least one or two interferometer antennas.  Probably need another stage for synchronous orbit though.

Gotta admit though, that car had a gorgeous color scheme against the earth’s and starry background.
I think it was red and black two tone, but you know how memory is,

Teslas LOL That guy lost my ground vehicle biz when he reneged on accepting BTC for that electric pickup truck..

NM already has a biggie, the VLA in Magdelena.

Giant dishes on Railroad tracks to allow focusing movement.

Run by the National Science Foundation, the tours are great.

73DG

You may need a Facebook account to see the vid, don't know where else to find it.
Work going on there, now.

https://www.facebook.com/PuertoRicoWire/posts/4693721633990240 (https://www.facebook.com/PuertoRicoWire/posts/4693721633990240)