The first Space Based Infrared System (Sbirs) missile warning satellite bound for geosynchronous (GEO) orbit is on track for delivery to the U.S. Air Force by the fourth quarter of calendar year 2010, according to its manufacturer.

This will be a major milestone for the $10.4 billion Sbirs program, which has undergone multiple restructurings, cost overruns and delays. Delivery of the first GEO satellite is at least 7 years later than planned and cost estimates have exceeded predictions by billions.

During a speech at this year’s Strategic Space conference here hosted by the Space Foundation, the general overseeing Strategic Command said he is worried about potential gaps in coverage for some mission areas in part because satellites are being delivered later than planned. U.S. Air Force Gen. Kevin Chilton used Sbirs as an example; all of the preceding Defense Support Program (DSP) satellites have been launched, and the Sbirs schedule has repeatedly slipped.

Following delivery, the integration of GEO-1 onto the rocket will take 45-60 days in preparation for launch from Cape Canaveral, Fla., according to Rick Ambrose, vice president of surveillance and navigation systems for Sbirs prime contractor Lockheed Martin. GEO-1 will augment and eventually relieve satellites in the existing DSP constellation.

Thermal vacuum testing is slated for completion on GEO-1 in the middle of this month, Ambrose adds. The trials include three cycles each of hot and cold environmental testing; the satellite is on its final round of testing in cold temperatures at Lockheed Martin’s Sunnyvale, Calif., manufacturing facility, Ambrose said during a Nov. 3 interview with Aviation Week.

Following this round of tests, about 30 days will be set aside to replace some small parts with issues discovered during the trials. One example is the replacement of a part that included tin, which is not suitable for use on the spacecraft.

In the first quarter of calendar year 2010, the full-up spacecraft will undergo the Final Integrated System Test (FIST) period, a series of tests on the entire system in ambient conditions.

In parallel with these efforts on the spacecraft, the company also is working to qualify the Sbirs flight management software for flight in space, Ambrose says. This software underwent an overhaul after officials discovered a possible fault that could reduce the satellite’s ability to go into a safe mode in the event of a on-orbit problem. Another Lockheed Martin satellite went dark only seconds after entering orbit, and officials suspect this flight management software contributed to the problem. The rework on the Sbirs software was a precaution to prevent a similar situation.

Meanwhile, GEO-2, which will launch about 14 months after GEO-1, is in the Baseline Integrated System Test phase, which precedes thermal vacuum trials.

The first two Sbirs payloads on classified host satellites in highly elliptical orbits (HEO) have been certified to execute two missions — missile warning and technical intelligence. The Air Force has ordered a third HEO payload as well as GEO-3, and long lead work has begun on HEO-4 and GEO-4.

Image: Lockheed Martin