The National Science Foundation (NSF), an independent US government agency responsible to promote science and engineering - is looking for partners to take over its share of operations for 10 telescopes.
What has left astronomers worried is the fact that the NSF is not close to make any permanent decision owing to the slow pace of discussions and the complex environmental reviews required to shut national facilities.
That leaves the future of the telescopes in limbo - and puts the careers of astronomers on edge, said a report in the journal Nature.
By offloading the old telescopes, the agency could free up about 10 percent of its $233-million astronomy budget.
That would not only allow more money for research grants but also let the agency buy future telescopes.
"Our job is to foster frontier science. Within a constrained budget, there is nothing you can do that is not going to hurt somebody," said James Ulvestad, head of the NSF's astronomy division.
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Astronomers at the Green Bank Telescope (GBT) - the world's largest fully steerable radio telescope at Green Bank in West Virginia - are deeply concerned.
"It's too early to be considering shutting this instrument down," said Anthony Beasley, director of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, which operates the facility.
"The GBT has not hit strong middle age yet," he added.
Still, the NSF says that it cannot afford the roughly $8 million required to operate the GBT annually.
"The NSF needs partners to contribute at least half of that cost or the facility could even be dismantled," said Ulvestad.
However, for astronomer DJ Pisano from West Virginia University, the issue is emotional to the core.
"Having done some great science with that telescope, I would hate to see it go," he quipped.