WASHINGTON — Despite recent, measurable progress on the U.S. Air Force’s new-generation missile warning satellite program, lawmakers remain concerned about the drawn-out timetable for fielding the system’s most advanced capabilities and about the service’s technology insertion plan for follow-on satellites.

Under current plans, the fifth and sixth satellites in the Space Based Infrared System (SBIRS) will be launching with 30-year-old focal plane technology, members of the Senate Armed Services Committee said in marking up their version of the defense authorization bill for 2014. The focal plane is the part of a SBIRS satellite’s missile-detecting infrared sensor that captures the relevant data.

In the report accompanying its bill, the committee directed the Air Force to assess the feasibility of inserting newer focal plane and other technology into the satellites, which are funded in the service’s 2014 budget request and slated for launch around 2020. Should that prove not to be feasible, the Air Force should explain how it plans to manage costs and risks on a future-generation missile warning system, the report, which was drafted June 14, said. 

The House Armed Services Committee, meanwhile, is primarily concerned about the slow pace of Air Force efforts to fully exploit the most advanced capabilities of SBIRS, whose missions also include technical intelligence and battlespace awareness. In its version of the authorization bill, the House panel recommended that the Air Force spend $42.5 million next year for SBIRS data exploitation, or $20 million more than the service requested.

When fully deployed, SBIRS will consist of four dedicated satellites in geosynchronous orbit, infrared sensors hosted aboard two classified satellites in highly elliptical orbit and a complex ground network. Lockheed Martin Space Systems of Sunnyvale, Calif., is prime contractor on the system, which took more than a decade and a half to develop and overran its budget by billions of dollars.

That said, the service in May declared the first dedicated SBIRS satellite operational — more than two years after its launch — and in March successfully placed the second satellite into orbit. The first and second elliptical-orbit SBIRS sensors were declared operational for the missile warning mission in December 2008 and August 2009, respectively.

In report language accompanying its version of the defense authorization bill, the House Armed Services Committee complained that SBIRS is not expected to achieve its full performance capability until 2018. “Full performance, which is driven by the ground segment schedule, includes final software tuning, algorithm integration, real-time data fusion, and automated tasking and cueing,” the report, released June 6, said. “The committee urges the Department to make further efforts to accelerate the schedule of the full performance of the SBIRS system.”

Much of the concern centers on the SBIRS staring sensor capability.  

Each geosynchronous SBIRS satellite has two main infrared sensors: a scanning sensor that sweeps over large swaths of territory watching for missile launches, and a staring sensor that can be trained constantly on a smaller area of interest to provide near-immediate notification of launches. 

The committee noted that at a budget hearing earlier this year, Gen. William Shelton, commander of Air Force Space Command, said the service was still working to maximize its use of SBIRS.

“We have not even scratched the surface, I think, of the potential that’s there. We have another sensor that we haven’t fully exploited yet as part of that satellite,” Shelton said, according to the authorization report language. “We’re doing a good job on the scanning sensor. The staring sensor, which has much better fidelity, we really haven’t fully wrung out yet, because we’ve been so focused on getting the scanning sensor calibrated and certified.”

The lawmakers directed the Air Force “to make further efforts to accelerate the schedule of the full performance of the SBIRS system.” They said “further data exploitation has the potential to enhance the effectiveness of the United States ballistic missile defense systems, particularly with the additional sensor data from the recent launch of the second SBIRS geosynchronous satellite.”

Concerns about the SBIRS staring sensor delay are not new. In March 2012, Shelton said the Air Force would not be able to fully exploit data from the staring sensors until 2016 or 2017.  That led Congress to add $40 million to the Air Force’s SBIRS budget for 2013 to accelerate the availability of that data.

The House authorizers are also attempting to thrust SBIRS into the ongoing battle over Operationally Responsive Space, a mostly experimental activity involving quick-reaction space capabilities that the White House wants to terminate. The House bill would fence off half of the $17 million the Air Force is seeking next year to develop new missile warning sensor technology pending certification that the Defense Department is continuing Operational Responsive Space activities — this generally refers to efforts to field low-cost space capabilities quickly in response to emerging military needs — as previously directed by Congress.

The Senate authorizers, meanwhile, have asked the U.S. Government Accountability Office to review the benefits and drawbacks of disaggregating certain Air Force space missions, including SBIRS. Disaggregagtion refers to the idea of breaking up payload sets on certain missions and dispersing the capabilities among smaller satellites.

The Senate lawmakers also want the Government Accountability Office to review a report they have requested from the Air Force on the service’s SBIRS technology insertion plan.

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...