An image of the Arecibo radio telescope in Puerto Rico taken by a SkySat satellite Aug. 10 shows the hole in the telescope's dish caused by a cable that broke earlier that day. Credit: Planet

WASHINGTON — A NASA official warned it may take several months to repair damage to the Arecibo radio telescope in Puerto Rico caused by a broken cable.

Speaking at an Aug. 17 meeting of NASA’s Planetary Science Advisory Committee, Lindley Johnson, director of NASA’s Planetary Defense Coordination Office, said he expected the giant radio telescope to be out of service for months. While Arecibo is primarily funded by the National Science Foundation (NSF), NASA does contribute some funding to use the telescope as a planetary radar to track and characterize near Earth asteroids.

A cable that is part of a system that suspends an observing platform above the telescope’s 305-meter primary dish broke in the early morning hours of Aug. 10. A section of cable fell to the dish below and created a gash about 30 meters long. The incident also damaged the platform itself.

Johnson said that the cable, about 7.5 centimeters in diameter, did not itself snap. Instead, the cable came out of its socket on one of three support towers surrounding the dish. The cable weighs about 30 kilograms per meter, and more than 200 meters of cable fell onto the dish. “That’s several tons of material crashing down onto the dish,” he said.

The timing of the accident, during the middle of the night, was fortunate. “They were scheduled to be doing some work on the reflector panels” later that day, he said. “It’s lucky there weren’t people down there working on the dish.”

Observatory officials are still determining the full extent of the damage, as well as a cost and schedule estimate for the repairs, but Johnson didn’t expect the telescope to be up and running soon. “This is going to be several months, certainly, that the antenna is going to be out of operation,” he said.

The repair work will be led by the NSF. “We’re here to support them in understanding what it is going to take,” he said, adding that none of the radar equipment used by NASA appears to have been damaged in the accident.

With Arecibo out of service, NASA is temporarily without a radar to aid in its planetary defense efforts. However, Johnson said that work replacing the radar system on a Deep Space Network antenna in California is nearing completion. A new klystron, which generates the radio signals used by the radar, has been installed on the antenna, and he estimated the radar should be in operation as soon as the end of the month.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...