"We are looking to diversify to soften the blow,'' he said.

Another company that expects to be hit hard by the budget cuts is Odyssey Systems.

"Hanscom is probably about a third of our business,'' said Mike Sweat, who left his job at the base in 1997 to start the firm. Back then he had two employees. Now, the company has about 325, he said.

Mike Kelley, a former Hanscom official who now works for Abacus Technology, whose Lexington division also provides support services to the base, believes some companies may not survive as a result.

"They're going to die if you take away 75 percent of their people,'' Kelley said.

Members of Congress are also expressing concern. Senators Scott Brown of Massachusetts and Kelly Ayotte of New Hampshire, both Republicans, urged the Air Force in a letter last week to "closely monitor the reductions at the Electronic Systems Center to ensure they are implemented in a manner that does not unfairly target small businesses.''

The Electronic Systems Center, activated in 1961, develops communications and electronics systems for the Air Force and has overseen the design of such mainstays as the large-domed early-warning aircraft known as AWACs. It was established in the Boston area in large part due to the proximity of MIT's Lincoln Laboratories and the federally funded Mitre Corp., which would not be affected by the proposed cuts.

Base officials say the center oversees about 200 large and small electronics, computers, and surveillance programs. It has an annual budget of about $5 billion and, according to industry groups, employs, both directly and indirectly, an estimated 16,000 people.

On top of the contractor budget cuts, however, the Air Force is also in the process of downgrading the Electronic Systems Center in the Pentagon chain of command. By Oct. 1, the facility will no longer be headed by a three-star general. It will be split into two directorates headed by a two-star officer who will report to a higher headquarters in Ohio, according to the documents obtained by the Globe.

That move means the center will also have to reduce its headquarters staff by 379 positions this year, according to Paone. It has not yet been determined if all of those jobs will be abolished or whether some will be transferred to Ohio.

Some former base officials worry that the cuts and the change in the center's status could set the stage for further reductions - especially if Congress adopts a controversial Pentagon proposal to close or consolidate excess military bases across the country.

"When you take away the three-star position and the headquarters staff that goes along with that, is that going to impact the assignment of new programs, or will they end up being assigned somewhere else?'' asked Charlie Benway, a former Hanscom official who is chairman of the board of the North Suburban Chamber of Commerce.

"We're not seeing these kinds of reductions in other Air Force bases,'' he added.

Davis, the Electronic Systems Center commander, maintained to the Globe that "there are no changes being made to our core mission.''

But people like Sweat, with experience as both a government employee and contractor at the base, wonder how the center will do its job with significantly fewer workers.

"They haven't developed the organic workforce to take the place of the contractors they would cut,'' he said.

James Cunningham, who retired as executive director of the Electronics Systems Center in 2005, is now president of the Lexington-Concord chapter of the Armed Forces Communications and Electronics Association, which represents some of the affected companies.

"There is a concern in the wider community,'' he said. "It is not a very good omen.''