WASHINGTON — Even as the U.S. Army prepares to tell Congress that its Warfighter Information Network-Tactical (WIN-T) program is more than 15 percent over budget, service leaders intend to ask for more money to field the mobile satellite terminal sooner.

The final calculations still are being done, but it appears that WIN-T costs have risen enough to require a report to Congress under the Nunn-McCurdy law, Army and Department of Defense officials said .

That cost growth largely was the result of changing requirements. The terminals are now slated to be the network backbone for the service’s mammoth Future Combat Systems program, and therefore must get smaller to fit aboard the vehicles.

But Army officials are getting ready to ask for even more money in the wake of a recent decision to speed up the effort and “increase the projected fielding of WIN-T to the entire Army,” said Col. Angel Colon, the Army’s WIN-T program manager.

That will add about $3 billion to the total estimated program cost, bringing it to roughly $10 billion through 2025, Colon said.

WIN-T was launched in the late 1990s to connect troops in ground vehicles to satellites and unmanned aerial vehicles. In September 2004, the service awarded a development-and-production contract for $7 billion through 2018 to prime contractor General Dynamics C4 Systems and subcontractor Lockheed Martin Mission Systems. At that point, the Army planned a five-year gestation for WIN-T.

But operations in Iraq and Afghanistan highlighted the need for mobile satellite communications, so the Army in 2005 ordered the program accelerated, with the goal of fielding terminals within two years.

But service leaders then changed their requirements; they wanted a smaller, lighter and less power-hungry terminal that would fit on the nascent Future Combat System vehicles.

“We were asked about a year ago to refocus our energies to smaller form factors that could fit into [Future Combat System] vehicles, including a liquid-cooled radio,” said Colon.

Colon said the extra development required the purchase of more gear: small satellite phones, antennas and modems.

The changes added costs — a total of $500 million, according to a March 15 Government Accountability Office (GAO) report on WIN-T. The GAO report also said the status of WIN-T technologies remains uncertain.

The cost increases have pushed the program more than 15 percent over its initial budget, said sources in the Defense Department , the Army and on Capitol Hill. By law, the Army must report to Congress about its plans to fund the program.

Sources said Army budgeteers are preparing the necessary paperwork in cooperation with officials in the Office of the Secretary of Defense. They expect the Pentagon to formally notify lawmakers within weeks.

The changes also pushed back the new delivery goal to 2009 for prototypes and 2013 for the first production units, according to Colon and the GAO report.

Service leaders want to get an undisclosed number of those prototype satellite terminals in some soldiers’ hands in two years or less.

“The WIN-T Program of record should be acted upon so as to provide a clear migration of WIN-T mature technologies to support ARFORGEN [Army Force Generation] units within the next 18-24 months,” wrote Lt. Gen. John Curran, who directs his service’s Capabilities Integration Center, in a Feb. 28 memo to service acquisition secretary Claude Bolton Jr. and top Pentagon weapons buyer Kenneth Krieg.

Army Force Generation is designed to increase unit readiness, in part by making the latest technologies available to soldiers.

As of late last year, Army leaders planned to spend $222 million on WIN-T in 2008.

But in recent weeks, Army leaders decided earlier this year to buy enough WIN-T gear to equip all Army units, and have sent a Program Objective Memorandum to the Office of the Secretary of Defense asking for more money for WIN-T, Colon said. He declined to say how much was requested.

Why the decision to accelerate WIN-T? Industry officials say new Army and Pentagon leaders recognized the value of mobile satellite communication systems and turned WIN-T into a key part of the Future Combat System.

“WIN-T used to be seen as a threat to [the Future Combat System] , but now it’s not,” said an industry source.

In fact, WIN-T is being specifically produced to provide the satcom backbone for the Future Combat System network, say Army officials.

But the Army’s grand plan to equip all its units with WIN-T may run afoul of a current program to supply similar but stationary satellite ground terminals called Joint Network Node-Network (JNN-N).

Since 2004, the U.S. Army has spent $2 billion on JNN-N, which is also made by General Dynamics C4 and is currently in use in Iraq. The JNN-N system uses a 2.4-meter satellite dish, larger than the WIN-T dish.

The official Army plan calls for replacing all JNN-N terminals with WIN-T ones by 2025. But the Army wants to speed up that replacement and buy fewer JNN-Ns, say Army officials.

“While JNN-N is ongoing, [U.S. Army Training and Doctrine Command] supports WIN-T,” Curran wrote in the memo.

Some of the WIN-T communications gear could be spiraled in to forces in combat, say industry officials.

But one congressional source, a Democratic staffer who works on the House Armed Services Committee, said there will likely be some budget restrictions.

“It is unlikely the Army will get all the funding it wants for both of these programs, given the current lack of clarity regarding what the Army wants to do,” the source said.

Even the Army’s overseers want to understand the problem a bit better. The Office of the Secretary of Defense commissioned a 120-day study in November to figure out how to proceed with battlefield networking, the congressional source said.