The victory by NATO in Kosovo was not without a price for the Navy's fleet of Pioneer unmanned aerial vehicles, based at Webster Field in Southern Maryland.

Two Pioneers flying reconnaissance missions over Yugoslavia were shot down by Serb fire during the last few weeks of the air war, the Navy said.

But Navy officials said that the Pioneers have been providing NATO commanders with valuable intelligence during the operation and that losing a couple is par for the course. The Pioneers have been flying relatively low during the NATO operation, using their surveillance cameras to gather information that otherwise might be difficult to get without risking pilots or expensive manned aircraft.

Crew members from Webster Field operating the Pioneers from a ship in the Adriatic Sea are not particularly distraught over the downing of two of their surveillance aircraft, according to Cmdr. Daniel Duquette, who commands the squadron that operates them.

"They understand in a war you're going to have losses," Duquette said in a recent interview. "They would rather have it be UAVs than airplanes and pilots."

Webster Field, an annex of Patuxent River Naval Air Station in St. Mary's County, is home to the Navy's only operational detachment of pilotless aircraft.

Six Pioneers and 28 crew members from Webster, under the command of Lt. Cmdr. Scott Winfrey, deployed to the Adriatic Sea in April aboard the USS Ponce, as part of the Kearsarge amphibious ready group.

The Pioneers, measuring 14 feet in length with a wingspan of 17 feet and powered by a 26-horsepower converted snowmobile engine, are small and awkward looking. They carry cameras that allow operators aboard the ship to monitor activities ashore.

Operating off the deck of the Ponce, the Pioneers have flown more than 80 hours of missions in the region and used their cameras to scout for enemy tanks and missiles and to assess damage from NATO bombs.

"The information they've gathered has been valuable," said Duquette, commander of Fleet Composite Squadron Six. "It helps with the big picture."

Now, as U.S. Marines and other NATO troops move into Kosovo as part of a peacekeeping operation, the Pioneers are continuing their work, keeping watch over retreating Serb forces.

The two Pioneers that were shot down, each bearing a price tag of around $750,000, are being replaced by two more from Webster Field, officials said.

The lost Pioneers were likely hit by Serb antiaircraft artillery fire, Duquette said, though he added it was possible they were hit by small-arms fire. One was shot down June 2 and the other May 24, according to the publication Inside the Navy, which first reported the losses.

The Pioneers, first deployed aboard a ship in 1986, made their combat debut during the Persian Gulf War. In one famous incident, Iraqi troops surrendered to a low-flying Pioneer.

The Pioneers faced a tougher threat in Yugoslavia than in the Gulf War, Duquette said. "We're seeing a very advanced air defense system," Duquette said. "It's a very different environment from what we saw in Desert Storm. In Yugoslavia, they're integrated into the landscape, and instead of a desert, there are lots of mountains and trees."

The Pioneers have been flying at a height well below their maximum altitude of 15,000 feet and at times were much closer than that to the ground, particularly when crossing mountains and ridges. "It may well be that they could been seen or heard from mountain tops," Duquette said. "It's possible they could have been targeted and shot down."

In case anyone is keeping score, Navy officials at the Pentagon point out that the Air Force lost at least three of its Predator unmanned aerial vehicles operating over Yugoslavia, while at least four of Army's Hunter unmanned aircraft have been downed.

Seabees Restore Building

For more than 30 years, the Old Capitol Pumphouse sat deteriorating on a pier jutting 125 feet into the Anacostia River below the Washington Navy Yard.

Built in 1906 for drawing water from the river to create steam heat for the Capitol building, the two-story brick structure was abandoned in the 1960s because of pollution in the water. It was trashed and became home to colonies of pigeons.

But officials from the nonprofit Earth Conservation Corps decided the building would make an ideal center for the group's Anacostia environmental action programs, and earlier this year, they managed to get the Navy to send in the Seabees to restore the facility.

Seabee reservists from Navy Mobile Construction Battalion 23, based at Fort Belvoir in Fairfax County, were given the job under a Pentagon program that allows the military to undertake community improvement projects as a way of training.

"This thing was a run-down, beaten-down building sitting over the water," said Cmdr. Barbara Sisson, commander of the battalion. "We certainly get to exercise our military building skills, and they get the benefit of free labor."

Nine Seabees, all reservists, went to work on the pump house March 1 and found the building in less than pristine condition. "This building was extremely dangerous to use," said Master Chief Petty Officer Horace Ellis, who oversaw the project.

The Seabees, using donated building materials, put up drywall, upgraded the bathrooms, installed a drop ceiling, refurbished doors and painted. They installed heating and air conditioning and repaired numerous holes in the flooring. They fixed the pier leading to the pump house. "The walkway was literally treacherous," said Chief Petty Officer John Johovic, a carpenter from Falls Church.

Now the pump house, with a gleaming new interior, is to serve as an environmental resource facility for the local community, complete with a library, computer room, fish hatchery and science lab. The Seabees are working on a new dock for the facility.

"Our goal was to reclaim this pump house for the entire community," Bob Nixon, head of the corps, said at a dedication ceremony and barbecue opening the renovated facility June 3. "The Seabees have been here day in and day out doing a terrific job."

The Earth Conservation Corps was created in 1992 with the twin goals of protecting the environment and providing opportunities for disadvantaged youth.

The Seabees often worked side by side with young corps members as well as with other people from the community. "They got so close, they bonded," Sisson said. "It's been a wonderful blending."

"When we started this project I didn't realize how much it would benefit the community," Ellis said. "Each day people come by and thank us for being here."

Military Matters appears every other week. Steve Vogel can be reached at vogels@washpost.com via e-mail.

CAPTION: Oneida Bailey, from Earth Conservation Corps, shares a laugh with Navy Chief Petty Officer John Johovic during the opening ceremony at the renovated Old Capitol Pumphouse.