FORT MEADE, Md. -- At computer cubicles deep inside the National Security Agency, the intelligence service that eavesdrops on America's enemies is undergoing a small revolution.
For the first time, NSA specialists are working with analysts from the National Geospatial-Intelligence Agency, a newer organization that studies data from spy satellites. The specialists share the NSA's latest bugged phone calls and e-mails by suspected terrorists. They study NGA infrared scans and radar images of Baghdad and other trouble spots.
The benefits of teamwork might be obvious. But the collaboration between the agencies -- the ''eyes" and ''ears" of America's spy systems -- marks a critical shift for a cloak-and-dagger crowd that for decades has fiercely resisted joining forces and that has been criticized for glaring intelligence failures before the attacks of Sept. 11, 2001, and the war in Iraq.
''The NGA and NSA are acting closer together now than any intelligence organizations in history," Joan A. Dempsey, a longtime CIA officer who now heads the President's Foreign Intelligence Advisory Board, said in a recent speech.
Officials say the previously undisclosed unit, code-named Geocell, has rushed real-time tips and warnings to field operatives as well as White House officials.
More than 24 joint-agency teams were posted together in Iraq, with scores more in other military commands. So many senior staff members have swapped headquarters billets that insiders speak of an ''exchange of hostages."
But few dispute the benefits.
''The payoffs of working together are immediately visible," Lieutenant General Michael V. Hayden, the NSA director, said in an interview at his office.
Collaboration is ''a win-win," agreed James V. Clapper Jr., the NGA chief.
The intelligence reform bill, signed by President Bush on Dec. 17, seeks to replicate that approach wherever possible. As a first step, Bush will name a national director of intelligence with increased authority over the estimated $40 billion budget and a mandate to fuse the nation's 15 spy services into a more coherent whole.
Calls for cooperation are not new, and the job is not expected to be easy. During the Cold War, each spy service developed a separate mission, budget, and bureaucracy. Over time, the agencies became riven by bitter rivalries, cultural clashes, and operational ''silos." Worse, they communicated in vertical ''stovepipes" that funneled critical information up to managers, but rarely across internal lines or to other agencies.
The NSA and NGA are an example. The NSA complex at Fort Meade is 36 miles from NGA headquarters in suburban Bethesda, but until recently, the two Pentagon-funded organizations could have been on separate planets.
During the Cold War, the NSA was the most secretive spy service. It still conducts some of the most sensitive operations, including bugging foreign leaders. It remains the largest intelligence service, with an estimated 40,000 employees and contractors collecting ''signals intelligence" from military bases, US embassies, and other facilities around the world.
The NGA, with 14,000 employees and contractors, was created in November 2003 to replace the outdated National Imagery and Mapping Agency.
Unlike the NSA, the NGA does not have a clandestine arm. Although it has grown increasingly digital, it produces millions of unclassified paper maps and charts.
Partly as a result of historic differences, the NSA and NGA have spent ''tens of thousands of man-hours" over the past three years trying to meld their systems and cultures, Hayden said. The agencies have rewired computer networks, retrained staff members, and reorganized operations.
''It's not as simple as laying fiber-optic cable down the George Washington Parkway," Hayden said. ''It's: 'Is my [computer] portal the same size as yours? Your portal is too small. I've taken a polygraph. Why haven't you?' "
Different rules have not helped. The NSA, which is hiring 1,500 people a year, uses a private company to conduct background checks for new hires instead of relying on government investigators. That reduced the NSA application-to-clearance time to 79 days from over a year. Yet it takes two to three times as long at the NGA.
The two spy chiefs meet for a joint briefing every few months to check progress, and to cut red tape. ''We're sort of using the