The U.S. Air Force's B-2 Spirit bomber is expected soon to achieve key milestones for improving its stealth and radar technology, sources said Aug. 13.

The first operational B-2 equipped with a new type of exterior coating is slated for delivery to its home base, Whiteman Air Force Base, Mo., within a week or so, according to officials at Northrop Grumman Corp., which built the bomber and is handling the coating effort. The aircraft actually is the second B-2 to receive the alternate high-frequency material (AHFM), but the first plane was a test asset, used at Edwards Air Force Base, Calif.

The Air Force plans to apply the new coating to its 19 other B-2s as they are brought to Air Force Plant 42 at Palmdale, Calif., for other work. Because about three planes are expected to make that trip each year, it will take about seven years to put the new coating on the entire fleet, Northrop Grumman officials said.

By replacing more than 3,000 feet of radar-absorbing tape now used to fill gaps in each aircraft's outer surface, such as those near maintenance access panels, the robotically applied AHFM is supposed to make it significantly easier to keep the B-2 flying. Every time routine maintenance is performed, the tape has to be removed and then reapplied and allowed to cure, so replacing it with AHFM will reduce the time it takes to do a maintenance job from several days to several hours.

Harry Heimple, manager of government requirements for Northrop Grumman Integrated Systems, told The DAILY that the new coating has been fully tested to ensure the aircraft's low observability is not impaired.

"In fact, we believe the customer is going to be extremely happy about that," Heimple said.

Meanwhile, a source close to the B-2 program said a contract award is expected by fall for the next phase of a radar antenna replacement effort. The new antenna, which Raytheon Co. will build and Northrop Grumman will install, initially is designed to resolve a radio-frequency conflict with commercial aircraft, but it also will make it easier to upgrade the radar's performance in the future, the source said.

The active electronically scanned antenna (AESA), now in a component advanced development phase, is supposed to move into a system development and demonstration phase. Installation of the new antenna on the B-2 fleet is slated for completion by 2011.