[ad_1]
An ongoing investigation into the December collapse of the iconic radio telescope at Arecibo Observatory in Puerto Rico offers preliminary evidence that a manufacturing problem may have contributed to the failure.
The telescope’s massive science platform, which weighed 900 tons, was suspended above the vast radio dish by three dozen support cables. But in August 2020, one of those cables slipped out of its socket; before the failure could be repaired, a second cable broke outright in November. The United States National Science Foundation (NSF), owner of the site, determined that the platform was too unstable to be safely repaired and decided to take the instrument out of service. Before that can happen, the collapsed telescope alone on December 1st.
Engineers have been investigating the cables since August and teams have been cleaning up debris and monitoring environmental concerns since the collapse, observatory director Francisco Cordova said in a panel discussion today (Jan.21). “Site clean-up and debris removal is really underway,” Cordova told the panel, which is focusing on small solar system objects like asteroids to inform the National Academies committee that is preparing the document that will shape planetary science priorities for the next decade. “In general, I think this is going in the right direction.”
Related: Terrifying footage shows massive Arecibo observatory radio telescope collapse
Cordova noted that the telescope’s azimuth arm, which aided in directing its instruments, and the dome suspended from it which contained the antennas and radar transmitter, have already been deleted from the site. Environmental engineers also collected two types of potentially hazardous materials that were used on the platform, he said.
The next priority is to remove the remaining platform debris; to achieve this material, the work teams deconstructed part of the enormous Arecibo reflective dish, which measures 305 meters in diameter. The observatory team is also evaluating how much of the antenna itself can be saved, Cordova said.
“There is still a lot of discussion about how much primary reflector can be saved and how to achieve it,” Cordova said. “For now, our focus is on safely removing the rig structure, and then we’ll look at it from there.
Simultaneously, two forensic investigations are assessing what caused the telescope to collapse. An investigation focuses on the so-called auxiliary cables. These 12 cables were added in the 1990s, when the observatory installed the massive hanging dome that distinguishes the telescope appearance in the movie “Contact” from her previous cameo in James Bond’s “GoldenEye”. The first cable to fail was one of those auxiliary cables, which slipped out of its socket where it connected to one of the three support towers surrounding the antenna.
“A preliminary investigation revealed that there was a manufacturing error in these cables – in particular, the placement procedure was not carried out properly, and this led to an advanced degradation of this structural element. particular, ”Cordova said. “But the final forensic investigation has yet to be completed.”
Related: Loss of Arecibo observatory would create hole that cannot be filled, scientists say
A second forensic investigation focuses on the main cables, which are the original construction of the telescope in the early 1960s. It was one of those main cables that broke in november, despite engineers’ estimates that it only carried about 60% of the weight it should have been able to support.
As they work, site engineers separate any debris that might be relevant to the two forensic exams. Additionally, Cordova said staff are evaluating the removed debris for their potential historical significance so the items can be preserved.
The clean-up and investigation processes are ongoing, Cordova said; In addition, NSF is working separately to understand the collapse and assess the future of the site, including for a report that Congress requested end of February.
And the answer may never be crystal clear. “Granted, there is usually not a single element that contributed, but a multitude of elements that contributed to the particular failure,” Cordova said. In addition to the age of the establishment, the past few years have been difficult for Puerto Rico. In 2017 Hurricane Maria hit the island and during 2020 it experienced more than 10,000 earthquakes.
“Basically we were shaking all the time; that definitely could have been a factor,” Cordova said. “This is always analyzed by the engineering teams.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. follow us on Twitter @Spacedotcom and on Facebook.
[ad_2]
Source link