NSF begins planning for decommissioning of Arecibo Observatory’s 305-meter telescope on account of issues of safety

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News Originate 20-010


November 19, 2020

Following a overview of engineering assessments that stumbled on danger to the Arecibo Observatory cannot be stabilized without possibility to construction workers and workers at the potential, the U.S. Nationwide Science Basis will originate plans to decommission the 305-meter telescope, which for 57 years has served as a world-class handy resource for radio astronomy, planetary, solar machine and geospace study.

The choice comes after NSF evaluated loads of assessments by self ample engineering companies that stumbled on the telescope construction is in hazard of a catastrophic failure and its cables might maybe possibly well now no longer have the selection to carrying the loads they had been designed to beef up. Furthermore, several assessments stated that any attempts at repairs might maybe possibly well place workers in potentially lifestyles-threatening hazard. Even in the tournament of repairs going forward, engineers stumbled on that the construction would seemingly conceal long-term balance issues.

“NSF prioritizes the protection of workers, Arecibo Observatory’s workers and guests, which makes this decision most valuable, although unhappy,” stated NSF Director Sethuraman Panchanathan. “For practically about six a long time, the Arecibo Observatory has served as a beacon for leap forward science and what a partnership with a neighborhood can survey like. Whereas here’s a profound change, we are in a position to be taking a peep for systems to back the scientific neighborhood and defend that stable relationship with the opposite folks of Puerto Rico.”

Engineers luxuriate in been inspecting the Arecibo Observatory 305-meter telescope since August, when one of its beef up cables unexcited. NSF licensed the University of Central Florida, which manages Arecibo, to make a choice all inexpensive steps and utilize on hand funds to address the narrate while guaranteeing safety remained the highest precedence. UCF acted quickly, and the evaluation route of used to be following its expected timeline, alive to by the age of the potential, the complexity of the manufacture and the aptitude possibility to workers.

The engineering teams had designed and had been ready to place in pressure emergency structural stabilization of the auxiliary cable machine. Whereas the observatory used to be arranging for supply of two substitute auxiliary cables, as neatly as two transient cables, a most valuable cable broke on the same tower Nov. 6. In step with the stresses on the 2nd broken cable — which will deserve to luxuriate in been neatly within its potential to operate without breaking — engineers concluded that the final cables are seemingly weaker than firstly projected.

“Management at Arecibo Observatory and UCF did a commendable job addressing this narrate, performing quickly and pursuing every that that you might maybe well explain possibility to avoid losing this unbelievable instrument,” stated Ralph Gaume, director of NSF’s Division of Tall Sciences. “Till these assessments came in, our request of used to be no longer if the observatory might maybe possibly well restful be repaired but how. But in the tip, a preponderance of recordsdata showed that we merely might maybe possibly well no longer enact this safely. And that’s a line we can no longer pass.”

The scope of NSF’s decommissioning thought would focal point highest on the 305-meter telescope and is intended to soundly defend other ingredients of the observatory that might maybe possibly well possibly be broken or destroyed in the tournament of an unplanned, catastrophic give design. The thought goals to purchase as great as that that you might maybe well explain of the final infrastructure of Arecibo Observatory, in snarl that it stays on hand for future study and tutorial missions.

The decommissioning route of entails constructing a technical execution thought and guaranteeing compliance with a chain of dazzling, environmental, safety and cultural requirements over the arrival weeks. NSF has licensed a high-resolution photographic search the utilization of drones, and is alive to by alternate recommendations for forensic evaluation of the broken cable — if such trip might maybe possibly well possibly be done safely — to behold if any contemporary proof might maybe possibly well expose the continuing plans. This work has already begun and might maybe possibly well restful continue one day of the decommissioning planning. Tools and other materials will seemingly be quickly moved to buildings commence air the hazard zone. When all most valuable preparations luxuriate in been made, the telescope shall be field to a controlled disassembly.

After the telescope decommissioning, NSF would intend to restore operations at sources equivalent to the Arecibo Observatory LIDAR facility — a notable geospace study tool — as neatly as at the visitor center and offsite Culebra facility, which analyzes cloud quilt and precipitation data. NSF would also glance to explore probabilities for increasing the educational capacities of the studying center. Security precautions on account of the COVID-19 pandemic will stay in discipline as appropriate.

Some Arecibo operations engaging the evaluation and cataloging of archived data serene by the telescope would continue. UCF secured enhanced cloud storage and analytics capabilities in 2019 through an agreement with Microsoft, and the observatory is working emigrate on-space data to servers commence air of the affected residence.

Areas of the observatory that might maybe possibly well possibly be tormented by an uncontrolled give design luxuriate in been evacuated since the November cable atomize and might maybe possibly well restful stay closed to unauthorized personnel for the length of the decommissioning. NSF and UCF will work to lower possibility in the residence in the tournament of an sudden give design. NSF has prioritized a swift, thorough route of with the intent of conserving off such an tournament.

NSF recognizes the cultural and economic significance of Arecibo Observatory to Puerto Rico, and the design the telescope serves as an inspiration for Puerto Ricans alive to by training and employment in STEM. NSF’s aim is to work with the Puerto Rican authorities and other stakeholders and partners to explore the different of applying sources from Arecibo Observatory for educational functions.

“Over its lifetime, Arecibo Observatory has helped rework our figuring out of the ionosphere, showing us how density, composition and other components engage to shape this most valuable plight where Earth’s atmosphere meets residence,”  stated Michael Wiltberger, head of NSF’s Geospace Share. “Whereas I’m disappointed by the loss of investigative capabilities, I imagine this route of is a most valuable step to defend the study neighborhood’s potential to make utilize of Arecibo Observatory’s other sources and optimistically be obvious most valuable work can continue at the potential.”

Engineering summary

Arecibo Observatory’s telescope contains a radio dish 1,000 feet (305 meters) huge in diameter with a 900-ton instrument platform inserting 450 feet above. The platform is suspended by cables linked to just a few towers.

On Aug. 10, 2020, an auxiliary cable failed, slipping from its socket in a single of the towers and leaving a 100-foot nick in the dish under. NSF licensed Arecibo Observatory to make a choice all inexpensive steps and utilize on hand funds, which amounted to millions of greenbacks, to obtain the evaluation and kit wanted to address the narrate. Engineers had been working to set up the most sharp technique to repair the danger and identify the integrity of the construction when a most valuable cable linked to the same tower broke Nov. 6.

The 2nd broken cable used to be sudden — engineering assessments following the auxiliary cable failure indicated the construction used to be stable and the planning route of to restore the telescope to operation used to be underway. Engineers subsequently stumbled on this 3-shuffle most valuable cable snapped at about 60% of what is going to deserve to luxuriate in been its minimal breaking strength for the length of a duration of aloof climate, raising the different of different cables being weaker than expected.

Inspections of the different cables revealed contemporary wire breaks on seemingly the most valuable cables, that luxuriate in been fashioned to the construction, and proof of extra special slippage at several sockets maintaining the final auxiliary cables, that luxuriate in been added for the length of a refit in the 1990s that added weight to the instrument platform.

Thornton Tomasetti, the engineering company of legend hired by UCF to assess the construction, stumbled on that given the likelihood of one more cable failing, repair work on the telescope — at the side of mitigation measures to stabilize it for extra work — shall be unsafe. Stress assessments to seize a more precise measure of the final cables’ strength might maybe possibly well give design the construction, Thornton Tomasetti stumbled on. The company suggested a controlled demolition to set aside away with the hazard of an sudden give design.

“Although it saddens us to develop this suggestion, we imagine the construction might maybe possibly well restful be demolished in a controlled methodology as quickly as pragmatically that that you might maybe well explain, ” stated the suggestion for trip letter submitted by Thornton Tomasetti. “It’s miles therefore our suggestion to snappy thought for decommissioning of the observatory and produce a controlled demolition of the telescope.”

UCF also hired two other engineering companies to present assessments of the narrate. One suggested rapid stabilization trip. The different, after reviewing Thornton Tomasetti’s model, concurred that there will not be any such thing as a route of trip that might maybe possibly well safely take a look at the construction’s balance and suggested against allowing personnel on the telescope’s platforms or towers.

“Serious work stays to be done in the residence of atmospheric sciences, planetary sciences, radio astronomy and radar astronomy,” UCF President Alexander N. Cartwright stated. “UCF stands ready to develop the most of its skills with the observatory to hitch other stakeholders in pursuing the originate of commitment and funding wanted to continue and manufacture on Arecibo’s contributions to science.”

After receiving the contracted assessments, NSF brought in an self ample engineering company and the Military Corps of Engineers to overview the findings. The company NSF hired concurred with the solutions of Thornton Tomasetti and expressed narrate about indispensable hazard from uncontrolled give design. The Military Corps of Engineers suggested gathering extra photographic proof of the potential and a total forensic evaluation of the broken cable.

Given the incontrovertible truth that any stabilization or repair narrate would require workers to be on or approach the telescope construction, the extent of uncertainty about the cables’ strength and the crude forces at work, NSF well-liked the suggestion to prepare for controlled decommissioning of the 305-meter telescope.

-NSF-

Media Contacts


Media Affairs, NSF, (703) 292-7090, email: media@nsf.gov

The U.S. Nationwide Science Basis propels the nation forward by advancing fundamental study in all fields of science and engineering. NSF supports study and other folks by providing facilities, instruments and funding to beef up their ingenuity and retain the U.S. as a world leader in study and innovation. With a fiscal year 2020 funds of $8.3 billion, NSF funds attain all 50 states through grants to practically about 2,000 colleges, universities and establishments. Each and each year, NSF receives more than 40,000 aggressive proposals and makes about 11,000 contemporary awards. Those awards consist of beef up for cooperative study with alternate, Arctic and Antarctic study and operations, and U.S. participation in global scientific efforts.

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