The iconic Arecibo Observatory in Puerto Rico was damaged last week when a large cable fell onto the radio telescope’s main reflector dish. We’re now learning more about this unfortunate incident, including how long it might take until the beleaguered observatory is back online.
During the early morning of Monday August 10, a thick auxiliary cable used to support a metal platform dropped onto the main reflector dish, producing a 30.48 m-long gash. The golf ball-like Gregorian Dome was also damaged, as was a platform used to access the dome, which houses a multi-beam receiver. No one was hurt during the incident, but scientific work at Puerto Rico’s famous Arecibo Observatory is now on hold, pending repairs.
During a virtual press conference held on August 14, Francisco Córdova, the director of the Arecibo Observatory, described it as an “unprecedented event,” saying the cables, which were installed around 20 years ago, were supposed to last for another 15 to 20 years. Importantly, however, the cable did not snap. Rather, the 7 centimetre thick cable slipped out from a socket located on one of the observatory’s three support towers, he said.
The exact cause of the failure is still unknown. Ray Lugo, director of the Florida Space Institute, is now overseeing the investigation, which is still in its early stages, as he explained during the press conference. Lugo refused to “speculate about a timeframe” for the repairs, saying the investigation is the current focus, as is the need to protect people working at the facility. Only until a reason for the failure is determined can a timeframe for repairs be established, he said.
Lindley Johnson, director of NASA’s Planetary Defence Coordination Office, was more forthright during an August 17 meeting of NASA’s Planetary Science Advisory Committee, saying Arecibo will probably be out of commission for “several months,” as SpaceNews reports.
The Arecibo Observatory is primarily funded by the National Science Foundation (NSF), but NASA also contributes to the observatory, which it uses to track and study near-Earth asteroids.
“Damage to Arecibo is still being assessed by the Observatory management at the University of Central Florida, after which the NSF will consult with stakeholders, including NASA, to determine how to proceed,” explained a NASA spokesperson in an email.
Over 199.64 m of cable fell onto the dish, and given that the cable weighs 30 kg per metre, that’s “several tons of material crashing down onto the dish,” Johnson said. Radar equipment used by NASA was not damaged, he added.
Córdova said 250 primary reflector panels were damaged by the falling cable, as were several support cables underneath the primary dish. The “priority is not replacement,” he said, given the dish is fitted with 40,000 panels. This is “not a huge deal,” as the “primary reflector is in good shape,” he said. More complicated right now is knowing if the platform has retained the structural integrity required to continue operations and “whether it’s safe for the team to be up there,” Córdova said. Thankfully, he doesn’t expect to find damage inside the Gregorian Dome, including to its receivers and transmitters.
The investigators do not yet know if Hurricane Maria, which ravaged the island three years ago, had anything to do with the failure. A variety of astronomical work is now on hold, as is an investigation into gravitational waves and NASA’s planetary defence project to track near-Earth asteroids, explained Córdova.
The iconic observatory, in addition to coping with ongoing fiscal uncertainty, experienced some damage when Hurricane Maria ripped through in 2017. For the team at Arecibo, this latest setback is just “another bump in the road,” said Córdova, to which he added: “We’re a fairly pretty resilient bunch, and we proved that after Maria.”