WASHINGTON - The government wants to build a new generation of spy satellites and will buy more commercial imagery from the private sector to plug immediate gaps in satellite coverage, the top U.S. intelligence official said Tuesday.

The new program will replace a satellite program that was being built by The Boeing Co. The Pentagon canceled that program in 2005 because it was over budget and behind schedule.

National Intelligence Director Dennis Blair said the new spy satellites would be similar to those already in orbit, which were built by Lockheed Martin.

The plan will have to win congressional approval. Sen. Kit Bond, R-Mo., the top Republican on the Senate Intelligence Committee, has already complained about the price tag, which he put at more than $10 billion.

Blair did not reveal the program's cost or details about the new space craft program.

The program, known inside the intelligence agency and Pentagon as "2-plus-2," calls for building two sophisticated satellites equal to or better than the huge, high-resolution secret satellites now in orbit.

At the same time, the government would also commit to spend enough money on commercial satellite imagery sufficient to pay for the construction and launch of two new commercial satellites, according to military, intelligence and industry officials familiar with the program. All spoke on condition of anonymity because the details of the program are classified.

Blair and Defense Secretary Robert Gates rejected an alternate satellite proposal from military officials at the Pentagon, the officials said. The uniformed military favored developing and launching two new satellites that would be able to observe targets with better resolution than their commercial counterparts. The military maintains its preferred satellites would be faster, cheaper and less technologically difficult to build than the larger satellites envisioned in the proposed "2-plus-2" plan, officials said.

The "2-plus-2" program is meant to avert a potential gap in U.S. imagery satellite coverage around the world. The sophisticated spy satellites now in orbit are nearing the end of their service life, and replacements must be launched in the next decade to prevent blind spots.

The Defense Department spends about $20 billion annually on space programs.

The satellites in use now by the government tend to be high-altitude, expensive units that provide the finely detailed imagery required by intelligence and military officials. The new system backed by Bond and military officials would rely on a new class of more numerous, less-expensive, lower-orbiting satellites, but their track record is not yet proven.

The House and Senate intelligence committees have criticized the Pentagon and intelligence agencies' management of their space programs, noting that half the programs have exceeded their budgets by 50 percent or more.

If approved by Congress, the "2-plus-2" program would almost certainly mean a multibillion-dollar contract for defense giant Lockheed Martin, headquartered in Bethesda, Md.

The only other company with the facilities to build and test a massive satellite is Boeing, headquartered in Chicago. Boeing was the prime contractor on the Future Imagery Architecture, the secret satellite system that the Pentagon canceled in September 2005.

Boeing spent nearly $10 billion developing the secret satellite but ran into technical problems. After Boeing exceeded its budget by $3 billion to $5 billion, the Pentagon pulled the plug, according to industry experts and government reports.

The military spends about $25 million a month on commercial satellite photos from two companies, DigitalGlobe of Longmont, Colo., and GeoEye of Dulles, Va.

Those satellites, which can detail the outlines of 16-inch objects from space, are built by Ball Aerospace & Technologies Corp. of Boulder, Colo.; General Dynamics Advanced Information Systems of Fairfax, Va.; ITT Corp. Space Systems Division of Rochester, N.Y.; and Lockheed Martin.