The famous Ci Resibo Telescope, on the verge of collapse, will be demolished Science

The long and productive life of the Arecibo Telescope is over. The National Science Foundation (NSF) announced today that it will cancel the iconic radio telescope in Puerto Rico, which has led to the destruction of the structure due to two cable breaks in recent months. The 57-year-old observatory, which survived several hurricanes and earthquakes, is now in such a precarious position that attempts to repair it endanger staff and workers. “It’s not an easy decision to make,” Sean Jones, assistant director for mathematics and physical sciences, told a news briefing today. [the research] Community and Puerto Rico. “

At the briefing, the agency wants to maintain other on-site equipment, as well as a visitor and outreach center, said Ralph Gaume, director of the NSF’s astronomy department. But if that telescope structure is likely to collapse. It will bring a 900-ton instrument platform, suspended 137 meters above the 305-meter-wide dish, broken down. Flanging cables could damage other buildings on the site, as if three support towers had also collapsed. “There is a serious risk of an unexpected and uncontrolled collapse,” Gaume said. “Controlled demotion gives us the opportunity to preserve valuable assets near the observatory.”

Over the next few weeks, engineering companies are developing plans for controlled dissolution. This may include letting the platform explosively release from its cable and let it fall.

The Arecibo Telescope has been widely used by astrophysicists as well as atmospheric and planetary scientists since the early 1960s. For many years it was the main means of listening to the messages of the cultures of the outside world, and with its attractive appearance it was able to win supporting roles in feature films.

The observatory has been littered with elements for years, most recently Hurricane Maria in 2017 and the December 2019 earthquake and aftershocks. It is unknown whether these tensions contribute to cable failures, the first of which occurred on 10 August. Auxiliary cable, installed in the 1990s, when 300 tons of new equipment was added to the suspended platform, broke from one end of its socket, damaging some equipment and cracking the surface of the dish below.

Engineers investigating the break ordered the replacement cable and others to be supported. During their study, they found that one of the 12 main suspension cables – a failed auxiliary cable connected to the same tower – had dozens of broken wires around its exterior. Because these 9-centimeter thick cables are made of 160 wires, they thought they had enough capacity to shoulder the extra load.

But on November 7, that cable broke. The University of Central Florida (UCF), which leads a facility-run consortium for the NSF, already had three engineering companies on site to assess the breakup. They quickly set about analyzing the security of the entire constitution. The NSFA sent another firm and the Army Corps of Engineers. Three out of five said the only way forward was controlled demolition. If a major cable operates below its design capacity, “now all cables are questionable,” said Ashley Zouder, NSF’s program director at the Arecbo Observatory. If even one of the remaining three main cables connected to the damaged tower fails, the engineers conclude, the platform will break.

The NSF, in recent years, has been trying to reduce its commitment to the Arecibo Observatory and, by handling its operations, the UCF is increasing the economic burden. But Gaume said: “This decision has nothing to do with the scientific qualifications of the Arecibo Observatory. It’s a matter of safety. The facility still has powerful and unique capabilities on which researchers rely, he said. He added, “I am confident of the resilience of the astrophysics community, and the NSF is working with some of its other facilities to take some of the stalled studies.