The Green Bank Telescope (GBT) is the centrepiece of the Green Bank Observatory in West Virginia.
One of the telescope’s many research tasks is the search for extra-terrestrial intelligence – it listens for signs of communication or activity by species that are not from Earth.
The telescope and the town of Green Bank sit at the heart of the National Radio Quiet Zone – a 13,000 square mile area (33,670 square km) where certain types of transmission are restricted so as not to create interference to the observatory and a US intelligence agency outpost.
There is no mobile phone or TV signal and you cannot have strong wi-fi – although newer wi-fi standards do not interfere with the same frequencies as before.
But the effects from the global recession may mean the telescope is under threat.
The National Science Foundation is consulting on whether they can justify the expense.
The BBC’s North America technology reporter, Dave Lee, finds out more.