Three-quarters of staff at the largest satellite communications station in the world could lose their jobs after BT said it planned to scale down the site.
Only one of Goonhilly's dishes, Arthur, will remain after 2008
Ninety of the 120 workers at Goonhilly, in Cornwall, could lose their jobs or be redeployed, as satellite operations are moved to Madley, in Herefordshire.
An internal BT report says the move would help the firm centralise and remain competitive, the BBC can reveal.
Only one of the station's 61 dishes, Arthur, would remain under the plan.
Sub-sea cable operations will continue at the site, which covers 65 hectares (160 acres) of The Lizard peninsula in south Cornwall and is the largest station in the world in terms of land area and the number of antennas.
Goonhilly's first dish, Arthur, was built to receive the first live transatlantic television broadcasts from the United States via the satellite Telstar in 1962.
It is now a Grade II listed structure and is therefore protected.
Goonhilly received the first live TV broadcasts from the US
Goonhilly currently handles about 10 million telephone calls a week as well as computer data from the Atlantic and Indian Ocean areas, but its TV operations have been wound down over the years.
The move out of Goonhilly was recommended following a three-month review by BT.
A decision is expected to be confirmed by BT executives later this year, with satellite communications ending by 2008.
Kelvin Ball, head of radio, subsea and satellite communications for BT, said: "The view of the BT committee which considered this matter is that it is no longer commercially viable for satellite communications to continue at both Goonhilly and Madley.
"These recommendations have not been taken lightly. We need to reduce our running costs if we are to remain competitive in this fiercely competitive marketplace.
"Having considered all aspects, it was clear that the Madley site, in Herefordshire, was best suited to continue, primarily because of its more central location in BT's UK network.
"Other activities carried out at Goonhilly, such as the sub-sea cable operations, project management and health and safety, will continue."
Staff were told the news at a meeting on Tuesday afternoon.
Mr Ball said they were "completely shocked" at the move, but BT wanted to avoid any compulsory redundancies through redeployment and retraining.
The future of the visitors centre, which attracts 80,000 people a year, was being reviewed "with a view to it hopefully continuing".