The Arecibo Observatory in Puerto Rico, for decades the home of the world’s largest radio telescope, will be an astronomical observatory no more. The U.S. National Science Foundation (NSF) last week said it intends to transform the facility, which suffered fatal damage to its massive dish in 2020, into a center for education and outreach in science, technology, engineering, and math (STEM).
According to an NSF spokesperson, the transition “allows the community to imagine new possibilities for science and technology in Puerto Rico, including but not limited to the astronomical sciences.” But the new plan likely signals an end to the possibility that Arecibo will continue to operate primarily as a research facility and that its large telescope will be rebuilt, as some scientists had hoped.
“STEM education is a completely different business,” says Julie Brisset, principal investigator of the observatory and an astronomer at the University of Central Florida (UCF), which operates the facility for NSF. “We were not surprised … but were disappointed that this was the outcome.”
Built by the U.S. military in the 1960s and taken over by NSF in 1969, Arecibo’s 305-meter dish was a multitalented instrument. Its vast size—overtaken only by China’s Five-hundred-meter Aperture Spherical radio Telescope in 2016—made it exquisitely sensitive to faint radio sources such as collapsed stars called pulsars and subtle shifts of ionized gases in Earth’s ionosphere. It also boasted a radar transmitter that made it the world’s foremost instrument for studying Solar System bodies by bouncing radio waves off their surfaces.
The telescope survived well beyond its expected life. But in 2020, after battering by hurricanes and an earthquake, several cables supporting its 900-ton instrument platform high above the dish snapped. On 1 December 2020, the whole platform came crashing down. A forensic report commissioned by NSF concluded that a combination of factors, including poor cable manufacture and inadequate maintenance, had caused the accident.
NSF was already trying to reduce its spending on Arecibo in order to fund other newer instruments that are higher priorities for scientists. UCF, the latest in a series of contractors, took over in 2018 with the understanding that NSF funding would decline over its 5-year term from $8 million to $2 million. Brisset says the facility currently costs about $7 million annually to run.
NSF is now asking for proposals to transform the observatory into the Arecibo Center for STEM Education and Research, offering funding totaling $5 million over 5 years. It says the funding does not include support for remaining instruments at the site, including a 12-meter radio telescope, a radio spectrometer, and a suite of optical laser instruments for studying the upper atmosphere, known as lidar. “Scientists and engineers envisioning future projects, using the 12-meter radio telescope or lidar, may propose and coordinate with NSF and the new managers of the reimagined center any requested educational or science usage of the facilities,” the NSF spokesperson says.
Hopes of constructing a new large telescope at Arecibo appear remote. Since the telescope’s collapse, Arecibo staff and other researchers have drawn up an array of plans for a replacement. But several recent reports designed to help the U.S. research community set funding priorities—largely produced before the telescope collapsed—noted that much of the research performed at Arecibo can now be done elsewhere. One review said Arecibo’s ability to discover new pulsars had been unmatched. And for radar studies of Solar System bodies, “There’s no comparable instrument on the planet,” says astronomer Joanna Rankin of the University of Vermont. Right now, with its complementary instruments and experienced staff, Arecibo is a good bet for building a new instrument. “If those are allowed to wither and you’re going to build a next-generation telescope, you might as well build it somewhere else,” Brisset says. “Without those assets, the Arecibo site will be a harder sell.”
The observatory has always been “brilliant” at STEM education and outreach, Rankin says, welcoming about 100,000 people per year to its visitor center and training teachers from all over Latin America. But part of that success, she says, was due to the presence of a strong research program. Arecibo “could have that role because the education part was on the same grounds as a place carrying out remarkable science in three different fields,” she says.
Astrobiologist Abel Méndez of the University of Puerto Rico, Arecibo, also fears any new education center won’t have the same impact if the observatory’s research program fades. “It’s a shame, especially for the education and science of Puerto Rico,” he says. “It’s definitely something we will miss.”