WASHINGTON — The U.S. Air Force’s Transformational Satellite program, a futuristic communications system with a $26 billion price tag, has been canceled as part of the Pentagon’s 2010 budget request to Congress, U.S. Defense Secretary Robert Gates announced April 6.

Instead, the Air Force will buy more previous-generation military communications satellites, Gates said.

The Air Force has spent more than $1.5 billion to date on design studies of the Transformational Satellite, or T-Sat, system, which was intended to yield dramatic increases in the amount of secure bandwidth available to the U.S. military, including strategic forces and tactical units on the move. Boeing Space and Intelligence Systems of Seal Beach, Calif., and Lockheed Martin Space Systems of Sunnyvale, Calif., were competing for the T-Sat space-segment prime contract, which was supposed to be awarded this year.

The program’s cancellation had been widely expected since U.S. President Barack Obama signaled his intent to rein in defense spending, which soared under his predecessor. T-Sat, in particular, was considered by many to be too technologically ambitious, and the program was restructured last year to try to bring down its cost and risk.

To fill the void left by T-Sat’s cancellation, the Air Force will buy at least two additional Advanced Extremely High Frequency (AEHF) satellites, Gates said. AEHF prime contractor Lockheed Martin is under contract to build three spacecraft and the Air Force was directed by Congress to buy a fourth, so the latest plan means at least six spacecraft will be built.

The Air Force also will order additional Wideband Global Communications satellites. Boeing is under contract to build six of those spacecraft and recently said it was ordering long-lead components for two more satellites, which would bring the total to eight.

Missile defense, which enjoyed unprecedented levels of investment under former U.S. President George W. Bush, also was targeted by the new administration. Overall, spending on Missile Defense Agency programs will be reduced by $1.4 billion next year, Gates said.

The president’s plan cancels the Multiple Kill Vehicle, an effort to deal with the vexing problem of distinguishing between active missile warheads and decoys by destroying all possible targets in the immediate vicinity. Lockheed Martin was prime contractor on that effort.

The controversial Airborne Laser, a Boeing-led program, will continue to receive funding but only for the first platform, which is expected to attempt its first missile shoot-down test this year. There will be no funding to build a second platform, which is based on a Boeing 747 jetliner.

Funding for the Ground Based Midcourse Defense system, the primary U.S. territorial shield, will be limited to those interceptors already under contract and to system maintenance and improvements. Plans call for having 44 interceptors in place at two sites: Fort Greely, Alaska, and Vandenberg Air Force Base, Calif.

Two programs, the Theater High Altitude Area Defense and Aegis Ballistic Missile Defense systems, are slated for funding increases next year in what will enable full-scale production of interceptors for the respective systems.

U.S. Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said research will continue on the Kinetic Energy Interceptor, a high-speed missile buster being developed by Northrop Grumman. Cartwright said systems designed to knock down missiles in their boost phase will be a focus of U.S. research but that the Pentagon was still trying to determine how the Kinetic Energy Interceptor might fulfill that role.

Meanwhile, the Pentagon intends to hire 13,000 civilian personnel next year to do work now performed by contractors. Over the next five years, that number will grow to 30,000, according to Pentagon officials.

The Pentagon has for the past couple months been indicating budgetary pressures would require significant changes, including the cancellation of programs. The changes also reflect a move away from priorities associated with traditional warfare to those better suited to fighting the likely counterinsurgency campaigns of the future.

The Pentagon’s $533.7 million budget request for 2010 is a 4 percent increase from the amount appropriated for 2009. But that figure includes $130 billion for the campaigns in Iraq, Afghanistan and Pakistan that were previously funded out of separate bills called war supplementals.