The Comanche (search) is out. Unmanned Aerial Vehicles (search) and nuclear-tipped bunker busters (search) are in.

The weapons are just three of the armaments affected by the Pentagon's plan to transform the military from one designed to fight Soviet armies in Europe to one that can target terrorists worldwide.

"They're trying to figure out how to fight the new trouble we have today. Obviously, the Cold War technology isn’t going to cut it," said Victoria Samson, a research analyst at the Center for Defense Information (search).

Secretary of Defense Donald Rumsfeld (search) "sees it as a new era. He says it's not good enough to be able to fight big armies, big air forces. We need lighter, more agile forces that can move more quickly, that have a smaller footprint. He sees this as a real transformation, not simply a cycle," said Phil Coyle, assistant secretary of defense and director of Operational Test and Evaluation under President Clinton.

With price tags in the billions and development time lasting decades, pulling the plug on these programs has been no easy task. But tough decisions have been spurred by battlefield testing in Afghanistan and Iraq, and defense policymakers hope that new weaponry will help the military adjust to the challenges of fighting an often lightly-armed but hard-to-reach enemy.

One major military advance is the use of weaponized UAVs, which have debuted successfully in Afghanistan and elsewhere. Although they have performed well, they were rushed to the field before they could be certified by the military, and the General Accounting Office (search) has raised questions as to whether they have been properly integrated into the fighting force.

"[Department of Defense's] approach to planning for, developing and fielding UAVs does not provide reasonable assurance that its investment in UAVs will facilitate their integration into the force structure efficiently," a March 18 GAO report stated.

Another major weapon being discussed is a bunker buster that could target hideouts and weapons labs deep underground. It is a weapon Pentagon planners have been seeking for a decade.

Coyle said the lightly-armored, mobile Stryker (search) vehicle, which runs on wheels rather than tracks, is one of the most important new weapons being developed. "The Iraqis call it 'the ghost' because it doesn’t make a lot of noise. It is faster and quieter than a tank, though more vulnerable."

But with a limited budget, not every weapon can stay in the arsenal. Cuts have been required among older, less useful equipment.

"Even though we've had a wildly expanding defense budget, they can't fund everything they want to. They realize that we are fighting a whole new war than under the Cold War. There are new threats. You need to change your thinking. You need to change your military technology to properly deal with them," Samson said.

Two high-profile programs that have been killed are the Crusader (search) missile and the Comanche helicopter. The Army canceled the Comanche last month after investing $6.9 billion and 21 years in the chopper.

These weapons were built for an outdated era, a Pentagon source said. "The Crusader was too heavy. It didn’t meet the needs. And Comanche was more of a Cold War weapon." The weapons under development now are "lighter, faster, more lethal to meet 21st century needs."

Part of the reason for dropping the Comanche helicopter was to put funds towards UAVs like the Hunter and Raven. The Army also has decided to upgrade its current fleet of Black Hawk (search) helicopters and push for more of them, senior army leaders said at a Pentagon news conference in February.

The Army dropped the Crusader artillery project two years ago after spending $2 billion. But the Pentagon hopes the canceled programs will not mean billions of dollars down the drain.

"They're going to try to use some of the technology from the Comanche. They are going to do this with a lot of programs. They are going to try to learn from what's already done and not repeat what's already been done," Samson said.

Although the Comanche is the only major project canceled this year, two others are in trouble: the V-22 Osprey (search) hybrid helicopter-airplane and the F/A-22 Raptor (search) fighter jet.

The Raptor is less detectable, capable of high speeds at long ranges and able to provide a pilot with improved awareness of surroundings through integrated avionics.

But as the military adjusts to new challenges, such a plane may not be the best investment. "The F-22 was really designed for the Cold War with Russian air defenses where you needed a very stealthy aircraft with great maneuverability and speed. Of course, in Iraq and Afghanistan we didn’t have that kind of situation in the slightest," Coyle said.

In addition, costs have grown so much that the Air Force had originally planned to buy 750 Raptor aircraft, but now can afford to purchase only 218 aircraft. Despite GAO concerns, the Pentagon has asked for $4.7 billion for the Raptor in the fiscal year 2005 budget, and it remains the Air Force's top priority.

The Raptor also has its backers in Congress. Sen. Ted Stevens, R-Alaska, vowed last week that the Raptor would be saved.

Politically, cutting programs can be very difficult because of the consequences for state and local economies as well as political capital lawmakers have invested.

"I'm not trying to say there's a military-industrial complex, but you have to admit that there are strong ties and sometimes that results in programs being kept about long after the military utility is gone," Samson said.

But funding for military projects has angered some budget watchdog groups.

"With record budget deficits and greater need to support our men and women in uniform, Congress needs to act swiftly and eliminate this platinum-plated boondoggle," said Keith Ashdown, vice president of policy at Taxpayers for Common Sense (search), of the Raptor.

Overall, military research and development aside from missile defense is not significantly larger in the Bush administration than it was in the Clinton years, Coyle said.

"There's a lot of money being spent on research and development, but I think that holds with U.S. policy," Samson said. "Because we have such a huge amount of funding to work with, we are allowed to have a trial-by-fire with development. We are allowed to be more open and flexible and look at the next big thing."