Arecibo's demise and possible rebuild.
 

[url=https://apnews.com/article/puerto-rico-radio-telescrope-to-close-b63df9ec84a876ab1c2e665f20e402e4]Arecibo[/url][quote]SAN JUAN, Puerto Rico (AP) — The National Science Foundation announced Thursday that it will close the huge telescope at the renowned Arecibo Observatory in Puerto Rico in a blow to scientists worldwide who depend on it to search for planets, asteroids and extraterrestrial life.

The independent, federally funded agency said it's too dangerous to keep operating the single dish radio telescope -- one of the world's largest -- given the significant damage it recently sustained. An auxiliary cable broke in August and tore a 100-foot hole in the reflector dish and damaged the dome above it. Then on Nov. 6, one of the telescope's main steel cables snapped, leading officials to warn that the entire structure could collapse.

NSF officials noted that even if crews were to repair all the damage, engineers found that the structure would still be unstable in the long term.

"This decision is not an easy one for NSF to make, but the safety of people is our number one priority," said Sean Jones, the agency's assistant director for the Mathematical and Physical Sciences Directorate. "We understand how much Arecibo means to this community and to Puerto Rico."
<snip>[/quote]

:xyzzy:

Let's hope another radio telescope, bigger and better, will replace this one

[QUOTE=Uncwilly;563813].[/QUOTE]
Phew! You worried me, posting Xyzzy in the RIP thread, without any comment... :razz:
I hope he is well and still kicking, hehe.

:razz:

You would think that in the 21st century with all the computer modeling and simulations and FEAs, Structural-Engineering would be an exact-Science. It is anything but.

[QUOTE=firejuggler;563823]Let's hope another radio telescope, bigger and better, will replace this one[/QUOTE]China's got a big radio telescope now. There was an installment of "Impossible Engineering" or some such series about it.

Alas, Arecibo now seems destined for a series like "Engineering Disasters."

Reading about the demise of Arecibo is quite depressing, and makes me feel my age, because I remember when it [i]started[/i]. I particularly recall a little oopsadaisy in the newspaper announcement, saying that the new telescope would be able to see 347 miles into space.
:grin:

[QUOTE=Dr Sardonicus;563833]China's got a big radio telescope now. There was an installment of "Impossible Engineering" or some such series about it.[/QUOTE]Bust the FAST in China does not have radar capability. Mapping NEO's needs the radar. Also Arecibo is much farther south allowing it to see much more of the sky. It also was part of the VLBA. And there are about 6 other reasons that it is a world gem.

[QUOTE=Uncwilly;563834]And there are about 6 other reasons that it [strike]is[/strike] [color=green]was[/color] a world gem.[/QUOTE]Fixed that for ya.

[QUOTE=a1call;563831]You would think that in the 21st century with all the computer modeling and simulations and FEAs, Structural-Engineering would be an exact-Science. It is anything but.[/QUOTE]

Weathering ... complicates things ... a bit.

[QUOTE=a1call;563831]You would think that in the 21st century with all the computer modeling and simulations and FEAs, Structural-Engineering would be an exact-Science. It is anything but.[/QUOTE]Quick, give the complete correlated load and corrosion history of every portion of the structure, in ANSYS input compatible form.

[URL]https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fwww.researchgate.net%2Fpublication%2F324020139%2Ffigure%2Fdownload%2Ffig5%2FAS%3A608605002809344%401522114148556%2FExperimental-S-N-fatigue-curves-of-DIN-34CrNiMo6-steel-for-different-stress-ratios-R.png&f=1&nofb=1[/URL]