The Pentagon appears to be redoubling its commitment to a new-generation missile warning satellite system with plans to order four additional dedicated spacecraft plus two more hosted sensors despite the program’s trouble-plagued history.

Lockheed Martin Space Systems of Sunnyvale, Calif., currently is under contract to deliver two dedicated Space Based Infrared System (SBIRS) satellites, which will operate in geosynchronous orbit, along with two sensors hosted aboard classified satellites in highly elliptical orbits. The hosted sensors are already on orbit; the first dedicated SBIRS craft is expected to launch in 2010 or 2011.

The company is ordering long-lead components for a third dedicated satellite and a third elliptical-orbit sensor under a contract that has not been finalized. Richard Ambrose, Lockheed Martin’s vice president and general manager of surveillance and navigation systems, said a final contract is anticipated in the next three to six months and will include a fourth dedicated satellite and a fourth hosted sensor.

Meanwhile, the U.S. Air Force was directed late last year to begin the process of acquiring the fifth and sixth geosynchronous-orbit SBIRS satellites, according to a Pentagon acquisition decision memorandum. “I direct the SBIRS Wing to negotiate undefinitized contract options” for the fifth and sixth geosynchronous satellites, said the Dec. 1 memo, signed by John Young, who at the time was undersecretary of defense for acquisition, technology and logistics.

The memo also authorized the Air Force to procure the third and fourth dedicated satellites and hosted sensors under a single contract. Young said the strategy will save some $200 million and directed the Air Force to seek a congressional reprogramming of funds for the fourth dedicated satellite in 2009, with full funding anticipated in 2011.

SBIRS, which will replace the Defense Support Program (DSP) missile warning constellation, has been plagued by cost growth and schedule delays since the contract was awarded in late 1996. The latest problems have been with system software, which showed bugs during testing and had to be redesigned.

U.S. Air Force Gen. C. Robert Kehler, commander of Air Force Space Command, said March 31 he has a medium to high level of confidence that SBIRS’s major issues are behind it but noted that Lockheed Martin is still working through the software issue. He said he expects the satellites to perform as advertised once on orbit and lauded the performance of the SBIRS sensors now operating aboard the classified satellites.

Nevertheless, the Pentagon is planning to order a separate missile warning satellite that would launch after the first two SBIRS satellites are slated to be on orbit. Kehler described that as a hedging strategy against the possibility that one of the first two SBIRS satellites is lost in a launch failure. The DSP constellation also has suffered degradation in recent months, notably the on-orbit failure of DSP 23, the last satellite in that series to be launched.

Ambrose said that should the Pentagon ultimately win approval for the Infrared Augmentation Satellite, Lockheed Martin would compete for the award with a different team than the one dedicated to SBIRS. Other potential bidders include Boeing Space and Intelligence Systems of Seal Beach, Calif., and Northrop Grumman Aerospace Systems of Los Angeles.

The Air Force would put the augmentation satellite on a fast-track schedule by waiving many of the requirements levied on SBIRS, Ambrose said. Lockheed Martin, for example, likely would offer a variant of its A2100 satellite platform, which the company uses for commercial telecommunications satellites.

The sensor, meanwhile, could be a clone of the Northrop Grumman-built SBIRS sensors hosted aboard classified satellites. These sensors do not feature all of the capabilities of the Northrop Grumman-built sensors that will fly aboard the dedicated SBIRS satellites.