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The National Science Foundation (NSF) will be deactivated Arecibo ObservatoryThe huge radio antenna after damage made the structure too dangerous to repair, the agency announced today (Nov.19).
The announcement came from scientists awaited a verdict on the fate of the iconic observatory after the damage to the complex wiring that supports a scientific platform of 900 tons suspended on the dish. In August a the cord has slipped out of the socket, but the engineers evaluating the situation found it stable; earlier this month, a the second cable broke unexpectedly, leaving Arecibo’s fate much more dangerous. After considering three separate technical reports, the NSF, owner of the property, decided that the facility is quite unstable since no way to repair the damage this does not put staff at undue risk.
“Our goal was to find a way to preserve the telescope without putting anyone’s safety at risk, “Sean Jones, deputy director of mathematics and physics at the NSF, said today at a news conference.” However, after receiving and reviewing the engineering assessments, we have not found any path let us do it safely. And we know that a delay in decision making leaves the entire structure at risk of uncontrolled collapse, unnecessarily putting people and additional structures at risk. “
Related: Losing the Arecibo Observatory would create a hole that can’t be filled, scientists say
“The telescope is currently at serious risk of an unexpected and uncontrolled collapse,” said Ralph Gaume, director of the NSF’s Division of Astronomical Sciences. “According to engineering assessments, even attempts to stabilize or test the cables could lead to accelerating the catastrophic failure. The engineers cannot tell us the safety margin of the structure, but they have warned NSF that the structure will collapse on its own in the near future. ”
Security concerns loom
During the press conference, officials stressed that the decision was based on safety priority, not a reflection of the scientific work that Arecibo has done in recent decades or may continue to do in the future, and that some hoped-for science will be lost with the structure.
“This decision has nothing to do with the scientific merits of the Arecibo Observatory,” Gaume said. “It’s not a consideration. It’s just safety.”
Guame added that the agency will work with scientists who had planned to use the Arecibo telescope and its other facilities in order to transfer planned research projects wherever possible. However, the facility was unique, particularly in its radar capability, which was widely used for the study asteroids close to Earth and other objects of the solar system.
“Some of Arecibo’s science will be transferred; some won’t,” Gaume said.
Officials also pointed out that if they manage to dismantle the telescope in a controlled manner, the Arecibo Observatory’s other assets – mainly, the visitor center, an on-site atmospheric science instrument, and a second atmospheric instrument on neighboring Culebra Island. – they should survive.
Collapse threatens a deactivation challenge
Both failed cables on Arecibo were connected to the same support tower. An engineering analysis completed after the second cable failed in November found that if another cable on that tower, dubbed Tower 4, fails, the platform would collapse into the plate and likely cause the towers to tip over. And because the cable support system is already so fragile, the engineers saw no way to safely assess the situation in more detail let alone stabilize it.
“What we are challenged with is a structure for which we do not understand the safety margins, the engineering approaches to better understand the safety margins involve considerable risk and the engineering approach to repair the structure appears to be highly dangerous.”
This means that the situation is so unstable that NSF cannot guarantee that the telescope will be deactivated in a controlled manner. Gaume and Ashley Zauderer, program director of the Arecibo Observatory at the NSF, said the agency hired engineers to develop a plan for controlled decommissioning. Creating that plan and gathering the necessary approvals will take several weeks, they added.
Officials also declined to provide an idea of what that strategy would look like, although they mentioned the possibility of considering helicopters or explosives.
Coinciding with the press conference, NSF provided an engineering report from the company that guides the analysis of the Arecibo telescope after the second failure, which offers some more details on the fate of the facility.
“We believe the facility will collapse in the near future if left untouched,” wrote John Abruzzo, Thornton Tomasetti’s chief executive. “Controlled demolition, designed with a specific collapse sequence determined and implemented with the use of explosives, will reduce the uncertainty and danger associated with collapse.”
The gravity of the situation stems both from the fact that two cables are already broken, and from the way in which three separate technical consultants were caught off guard by the second failure. “The three expert companies we involved didn’t provide any input or any suspicion that there was a problem,” Gaume said of the main cables after the August bankruptcy.
“I think it’s really a shame that this main cable failed before we had a chance to stabilize things,” said Zauderer.
NSF officials said their priority right now is on safely dismantling the radio dish and securing as many other facilities on site as possible. But they stressed that they are not shutting down the Arecibo observatory as a whole, that they recognize the facility’s importance to Puerto Rico, and that in the long term they want to secure the future of the site and the science it has been promoting for decades.
“We are discussing the dismantling of a steel and cable structure, but it’s really the people who have the ideas,” Zauderer said. “It is the idea of the discovery that led to the construction to begin with, it is the passion of the people who work at the observatory … continue to explore, learn, this is the true heart and soul of Arecibo”.
“It’s not the telescope that’s the heart and soul, it’s the people.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
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