One of the great icons of human curiosity, the Arecibo radio telescope, is going to be torn down, the National Science Foundation, its owner, announced Thursday. From its perch in the mountains of Puerto Rico, the observatory has served for decades as the vanguard of the search for alien civilizations and guarded the planet against killer asteroids.
The telescope, with an antenna 1,000 feet across nestled in a sinkhole valley and a 900-ton constellation of girders and electronics hanging in the air above it, was long the largest single antenna in the world, a destination for astronomers as well as a location for Hollywood movies like “Contact.” Like the rest of the island commonwealth, it has been lashed and damaged by hurricanes in recent years, and under financial duress, raising questions about the observatory’s future.
In the last three months, two of the cables that suspend that receiver platform over the dish have unexpectedly failed, leaving the entire structure vulnerable to an “uncontrolled catastrophic collapse” in the words of Ralph Gaume, director of the astronomy division of the National Science Foundation. He spoke in a telephone news conference Thursday morning.
As a result, the 900-ton platform of radio receivers and perhaps the towers from which the cables are hung would crash into the dish and possibly other buildings.
Trouble began on Aug. 10 when an auxiliary cable slipped out of its socket and gashed the antenna dish below. The observatory had already ordered a replacement and was still trying to figure out what had happened when, on Nov. 6, one of the main cables that support the receiver platform snapped. Both of the cables that failed were attached to the same support tower and Dr. Gaume said that engineers at the site believed that one more cable breakage from that tower would cause the whole thing to collapse.
The result, he said, was that the telescope could not be safely repaired.
In any event, Dr. Gaume said in the news conference, the engineers had concluded that the structure would collapse of its own accord in the future.
“Now all the cables are suspect,” said Ashley Zauderer, the Arecibo program director at the National Science Foundation.
Astronomers also used the observatory to map dangerous asteroids as they buzzed past Earth, and to measure the rotation rate of Mercury.
Employing the antenna’s exquisite sensitivity, they tuned in to the enigmatic clockwork blips of distant pulsars, discerning in their changing rhythms secrets of unworldly physics.
For years the site hosted the largest single radio antenna on the planet, only surpassed in 2016 by a new telescope in China that is 1,600 feet in diameter.
The Arecibo facility was originally built and run by Cornell University under contract to the Air Force Research Laboratory, partly out of a desire to understand the properties of objects like nuclear warheads tumbling through the upper atmosphere. As a result, it was built to be both a telescope and a planetary radar.
One of its directors over the years was the astronomer Frank Drake. He was famous for first pointing a radio telescope at another star for indications of friendly aliens, then for an equation, still in use today, that tries to predict how many of “them” are out there.
On Nov. 16, 1974, Dr. Drake beamed the equivalent of a 20-trillion-watt message toward M13, a cloud of about 300,000 stars some 25,000 light-years from Earth, as part of a celebration of an upgrade to the antenna.
The message consisted of 1,679 zeros and ones. Arranged in 73 rows and 23 columns, the bits formed pictures of a stick man, the radio telescope, a DNA helix, the solar system, the numbers 1 through 10 and more.
Before Dr. Drake sent it off, he tried out the message on his Cornell colleagues, including Carl Sagan, the author and proselytizer of the search for life in the cosmos. None of them could decode all of it. Maybe E.T. would be smarter when the signal finally reached somewhere, but the real point of such messages, Dr. Drake and Dr. Sagan always admitted, was to raise the consciousness of those of us back here on Earth and an awareness of our own status as cosmic travelers in an unknown and obviously weird universe.
The observatory has cemented a place in popular culture, with starring roles in movies like “Contact,” starring Jodie Foster, the James Bond film “Goldeneye” and episodes of the “X-Files” television show.
But the future of Arecibo has become precarious. In 2007, the National Science Foundation, which has run the observatory since the early 1970s on an increasingly tight budget, said the observatory might have to close if a partner could not be found to take on some of the financial load.
In 2011, Cornell turned over management of the observatory to SRI International and two managing partners, Universities Space Research Association and Universidad Ana G. Méndez, among other collaborators.
Since 2016, it has been managed by the University of Central Florida under a cooperative agreement with Universidad Ana G. Méndez and Yang Enterprises. The annual budget is about $12 million, including funds from NASA and the National Science Foundation, according to the University of Central Florida.