One of the most iconic astronomical observatories in the world has disintegrated irreparably. Now she threatens to collapse completely.
After two unexpected cable breaks, engineers found that the 1,000-foot (305-meter) radio telescope at the Arecibo Observatory was so structurally insolvent that any worker who tried to repair it would risk his life. So the National Science Foundation, which owns the Puerto Rico telescope, decided to decommission it.
Now engineers are racing to figure out how to safely deconstruct one of the world’s largest radio telescopes before it collapses on itself. The structure is so unstable that engineers cannot even approach it to assess the risk and timing of such a collapse.
“Even attempts to stabilize or test the cables could accelerate the catastrophic failure,”
“It’s like losing someone important in your life.”
In its 57-year life, the Arecibo telescope has hunted dangerous asteroids near Earth, searched for signs of extraterrestrial life, and discovered the first planet beyond our solar system. In 1974, Arecibo radiated the most powerful radiation the Earth had ever sent to communicate with potential aliens. In 2016, he discovered the first recurring rapid radio explosions – mysterious space signals that scientists now believe come from dead stars.
But Arecibo’s troubles began in August, shortly after Tropical Storm Isaiah passed over the island. An additional 3-inch-thick cable popped out of the socket on one of the telescope’s three towers and crashed into the reflective vessel below. He tore a 100-foot slit in the panels.
Then in early November, shortly before major repairs began, a 15,000-pound main cable from the same tower broke and crashed into a court. Engineers had thought the structure was still strong enough to avoid a second disaster – and this cable carried only 60% of the expected load capacity – but the damage proved them wrong. They decided that they could no longer trust any of the other cables.
Both failed cables supported a huge metal platform hanging over the vessel. If another cable from the same tower failed, engineers found, the platform would fall with it.
“The entire 900-ton platform will collapse into the main drive, and it is possible that the three main towers themselves, which are over 300 feet high, will collapse,” Gaume said.
Deconstructing the telescope means abandoning any chance of saving it, but this is the mode of action recommended by three engineering companies.
“This decision is not easy for the NSF to make. But human safety is our number one priority,” said Sean Jones, assistant director of the NSF’s Mathematics and Physics Directorate.
Through its rapid movement, NSF hopes to save a set of buildings located just below one of the telescope’s towers. In this way, the Arecibo Observatory can remain open, but without defining its characteristics.
“When I heard the news, I was completely devastated,” Abel Mendes, director of the Planetary Habitat Laboratory at the University of Puerto Rico in Arecibo, told Business Insider. He has been around the observatory since he was 10 years old and has worked professionally with it for the past decade.
“It’s hard to take. It’s like losing someone important in your life. Yes, 2020 is not good,” he said.
The United States has lost its best asteroid hunter and alien seeker
The loss of the Arecibo Telescope is a major blow to humanity’s search for extraterrestrial life, our ability to protect the planet from asteroids, and our entire field of radio astronomy.
Mendes said that although Arecibo did not detect potentially dangerous space rocks, this is essential for their investigation: The observatory can ping such objects with radar to decrypt their shape, rotation, surface characteristics and trajectory through space.
Without this data, it is much more difficult to understand whether an asteroid is moving toward Earth.
The Arecibo Observatory plans to work with scientists who intend to use the telescope to find ways to transfer their research elsewhere, Gaume said. Other NSF facilities – the National Radio Astronomy Observatory in Virginia and the Green Bank Observatory in West Virginia – could potentially take over some of Arecibo’s sciences.
However, Mendes said Green Bank is only 10% to 20% as sensitive to weak radio signals as Arecibo. Therefore, he believes that the death of the telescope effectively ends the US chance for a comprehensive project to search for radio waves from extraterrestrial technology.
“The only place we need to do something like this that would be sensitive or more sensitive than Arecibo is now FAST in China,” Mendes said, referring to a five-hundred-meter aperture spherical radio telescope in Guizhou Province. “The United States has lost all that ability because it doesn’t have Arecibo.”
Arecibo and FAST, Mendes said, were the “two big eyes” of the Earth in radio astronomy.
“If you observe a source of interest that is in the weak radio spectrum, you need two large radio telescopes: one pointing to something during the day and the other at night,” he explained. “If you lose Arecibo, then you lose the ability to observe – 24 hours a day – a weak source of radio signals.”
He added: “We only have one eye now.”
“We work against the clock”
It will probably take about five or six weeks to figure out how to safely deconstruct the Arecibo telescope. Engineers will assess their capabilities from a distance, with drones snapping aerial photos.
Engineers are also considering ways to gain extra time, potentially tilting the towers by a few inches to reduce the weight of the remaining cables.
“We’re working against the clock,” Gaume said.
The technical reports describing Arechibo’s death are embedded below.
If engineers can disassemble the telescope before it self-destructs, the Arecibo Observatory will still be able to conduct some research. Its LIDAR lasers can study the upper layers of the Earth and the ionosphere. It also has a facility on the island of Culebra, which collects data on clouds and precipitation.
Future researchers can also analyze archived data from the telescope.