WASHINGTON — Congressional appropriators are in lock-step with the U.S. Air Force on most of the Pentagon’s unclassified military space programs in the 2010 budget request, but the Senate and House of Representatives have differing views on whether to ramp up a next-generation missile warning satellite program amid continued difficulties with the system now in development.

At the same time, lawmakers remain concerned about the U.S. Navy’s Mobile User Objective System (MUOS), whose recently disclosed one-year delay likely will result in a gap in the service’s so-called narrowband satellite communications capacity. Development troubles continue to dog the Air Force’s Space Based Infrared System (SBIRS) missile warning effort, and the service requested $143.2 million in 2010 for a follow-on program called the Third Generation Infrared Surveillance system. The Senate will fully fund the follow-on program in its 2010 Defense Appropriations bill, which is expected to pass the week of Oct. 5. The House version that passed July 30 included $39.2 million for the program.

SBIRS consists of missile-detecting infrared sensors hosted by classified satellites in highly elliptical orbits and dedicated satellites in geosynchronous orbits. Two of the hosted payloads are now on orbit, but none of the geosynchronous satellites have been launched. The entire program has exceeded its original $3 billion cost estimate by some $7.5 billion, and the geosynchronous satellites are more than eight years behind schedule, according to language in the report accompanying the Senate bill when it came out of committee.

The Air Force and SBIRS prime contractor Lockheed Martin Space Systems of Sunnyvale, Calif., completed in June a 20-month overhaul of the software for the SBIRS geosynchronous satellites, which added some $750 million to the price tag. While the software fix appears to have been successful, parts quality issues have recently arisen that may push the launch of the first SBIRS geosynchronous satellite beyond its current late 2010 to mid-2011 launch date, the report said.

Air Force leadership remains cautiously optimistic that SBIRS ultimately will be successful, but wants to spend the next several years developing an alternative under the Third Generation Infrared Surveillance program.

“Hardware issues have nagged at [SBIRS] for some time, and we still have some of those hardware issues that we’re trying to work through here,” Air Force Gen. Robert Kehler, commander of Air Force Space Command, said at a Sept. 14 media briefing here. “I don’t know if there will be any other impacts to schedule and cost. “At the same time, we know that we need to get going on something beyond SBIRS, the question is when do we need that? … I’m not optimistic or pessimistic. We are where we are with SBIRS.”

As part of the Third Generation Infrared Surveillance program, the Air Force will host an infrared demonstration payload built by Science Applications International Corp. (SAIC) of McLean, Va., on an SES Americom communications satellite that will launch next year. In addition, SAIC and Raytheon Space and Airborne Systems of El Segundo, Calif., are each building more sophisticated payloads that will be tested on the ground in a few years.

Meanwhile, the Senate bill would also include a provision that would require the Navy to devise a strategy for acquiring ultra-high frequency satellite communications capacity amid ongoing delays with the MUOS program. The Navy’s current constellation of UHF Follow-On satellites is degrading and could reach an unacceptable level of performance by mid-2010, while the launch of the first MUOS satellite is not expected until 2011.

The Navy this year assembled a review team to address the technical, schedule and cost status of MUOS, and that team reported back in August that the program was technically sound but had an inadequate budget and unrealistic schedule, according to language in the Senate report. The program will be revamped in coming months to reflect the need for additional funding, it said.

The Navy would be directed within 90 days of the passage of the 2010 Defense Appropriations Act to review the options for obtaining narrowband capacity, the Senate report said. These options include putting a military communications payload on a commercial satellite or on the Operationally Responsive Space Office’s experimental Tactical Satellite-4. Until this strategy is delivered to the appropriate congressional defense committees, the Navy would be barred from spending $150 million of MUOS procurement funds, the report said. The Senate bill would fully fund the Navy’s $961.3 million for MUOS, while the House version trimmed $4.7 million from the request.