After decades of partnership with the U.S. government, American colleges are facing new doubts about the future of their federal funding.

SAN JUAN – A huge, already damaged radio telescope in Puerto Rico that has played a key role in astronomical discoveries for more than half a century completely collapsed on Tuesday. An auxiliary cable snapped in August, causing a 100-foot gash on the 1,000-foot-wide (305-meter-wide) dish and damaged the receiver platform that hung above it. The collapse stunned many scientists who had relied on what was until recently the largest radio telescope in the world. “It's a huge loss,” said Carmen Pantoja, an astronomer and professor at the University of Puerto Rico who used the telescope for her doctorate. “I am one of those students who visited it when young and got inspired,” said Abel Méndez, a physics and astrobiology professor at the University of Puerto Rico at Arecibo who has used the telescope for research.