TITUSVILLE, FLA. - NASA's giant Vehicle Assembly Building looms on the horizon, and the launch towers that have sent U.S. astronauts into space gleam in the bright spring sun near the Cape Canaveral shoreline.

But the familiar landmarks dotting the sprawling Kennedy Space Center complex are far from reassuring sights these days to residents of Florida's Space Coast.

They have lived through painful downturns in the nation's space program before and now fear tough economic times may hit again when NASA ends the space shuttle program in 2010.

This month the agency announced it may lay off as many as 6,400 workers from the Kennedy Space Center's work force of about 13,500. About 9,000 work directly on the shuttle.

The number is preliminary and could be far smaller, but the outlook is still clouded with uncertainty. A new manned space flight program, Constellation, is to take Americans back to the moon and beyond starting in 2015, but the new space vehicle will require far fewer workers and won't ramp up in time to absorb all the workers laid off as the shuttle goes out of service.

"I was here when the Apollo program was shut down in the early 1970s, and we went from 26,900 workers to 8,300 over about four years," said Lee Starrick, 66, who endured a two-year layoff then in his job as a fireman at the space center. "Every third house on my street was empty. People just packed up and left. They are saying this time it won't be so bad, but people are worried."

Though the projected job cuts will be the most severe in Florida, the shuttle's retirement will also trigger layoffs at other NASA installations, including the Johnson Space Center near Houston.

"We're concerned and will be affected, but nothing like in Florida," said Bob Mitchell, president of the Bay Area Houston Economic Partnership, which works to bring jobs to the area. "Most of the work here is engineering, development and astronaut training. We've been planning for this for the last 18 to 24 months and are already transitioning."

NASA says the Houston center might see as many as 2,300 layoffs, most of them, as in Florida, at private contractors who do shuttle work. The current work force at Johnson Space Center is about 16,800 workers, although only about 4,700 of them work directly on the shuttle.

Another hard-hit location will be the Michoud Assembly Facility in Mississippi just outside New Orleans, where 1,300 of the current 1,900 jobs would go, a severe blow in an area still struggling to recover from Hurricane Katrina. The Michoud facility prepares the shuttle's huge external fuel tank.

In Florida, officials estimate the that Kennedy Space Center pumps about $1.5 billion per year into the Brevard County economy, with an economic effect of $4 billion for the state as a whole. The average salary at the center is $69,000; the average in Brevard County is $35,000.

Although the county's economy is far more diversified than during the 1970s when Apollo was shut, the prospect of losing thousands of high-paying jobs is chilling.

"With Titusville being the closest city to the center, we'll take a pretty significant hit," said Marcia Gaedcke, president of the Titusville Chamber of Commerce. "We're very concerned, although now at least we have a solid estimate of the job losses and know what we have to overcome."

Softening the blow?

After watching their economy get flattened after the abrupt Apollo-era layoffs, Brevard officials have been working furiously to soften the blow.

Congressional representatives are working to extend the shuttle program by a year or two in an effort to close some of the gap until the moon program gets into full swing. The county also landed a contractor who will assemble the new Constellation crew capsule, Orion, at the Kennedy Space Center, a gain of 400 jobs that might go higher as the work progresses.

Officials are also actively courting private commercial space companies that are working to develop new rockets for hauling satellites -- and even tourists -- into space, as well as companies with no ties to the space program.

NASA administrators hope to shift many shuttle workers into new space jobs.

"We need other roles and missions to fill [the] void," NASA Administrator Michael Griffin told local reporters last fall. "Clearly impressed in my memory is the post-Apollo ghost town, and I don't want NASA to create another post-Apollo experience down here at the cape."

But like Houston officials, they think the public needs to know just how much the nation could lose if NASA makes drastic cuts.

"People have a Tom Hanks vision of what our space program is," said Lynda Weatherman, head of the Economic Development Commission of Florida's Space Coast, referring to the Hollywood actor and director's films about heroic U.S. astronauts.

"They need to realize the risks," she said. "Does middle America know that when the shuttle retires, the U.S. won't have the capability to launch humans into space, while Russia and China will?"