U.S. Air Force engineers have completed the first round of ground testing on the second Space-based Infrared System (SBIRS) missile-warning satellite, according to the Air Force.

During the four-month test regime, called baseline integrated system testing, the Air Force ran the satellite through 200 “scripted test events” at manufacturer Lockheed Martin’s plant in Sunnyvale, Calif. The Air Force would not say what constitutes a scripted test event, but said the tests on GEO-2, as the spacecraft is known, verified that its systems are working as expected. GEO-2 has to be subjected to one last battery of tests — a series of systems performance tests — in preparation for its 2012 launch.

The Air Force is developing a constellation of infrared satellites to detect and track ballistic missiles in their boost phases by spotting their unique infrared signatures. The satellites are meant to replace the decades old Defense Support Program constellation, which serves as an alarm bell for the U.S. anti-missile systems. The Air Force has launched two SBIRS sensors on classified satellites operating in elliptical orbits but the service is behind schedule on its plan to launch a geosynchronous constellation, starting with GEO-1 and GEO-2.

The Air Force has completed thermal vacuum testing on GEO-1 and is packaging the satellite in preparation for delivery to Cape Canaveral, Fla. later this year. The Air Force did not provide a launch date for GEO-1.

Subsequent tests on GEO-2 are to include acoustic and thermal vacuum tests, a final integration systems test and final configuration testing. The GEO-2 integration team is applying lessons learned from GEO-1 integration and is proceeding through spacecraft integration and testing, Space and Missile Systems Center spokeswoman Tonya A. Racasner wrote in an e-mail message.

GEO-1 should be available for operational use about 14 months following launch after spacecraft deployment, checkout, payload tuning and system certification. GEO-2’s availability should be quicker, about six months after launch.