WASHINGTON — As it prepares to launch the second satellite in its next-generation missile warning constellation, the U.S. Air Force continues to wrestle with a communications glitch on the first craft, which reached orbit almost two years ago but has yet to begin operations.

Air Force Col. James Planeaux, director of the Infrared Space Systems directorate at the Air Force Space and Missile Systems Center in Los Angeles, said March 12 that officials discovered the irregularity with the first dedicated Space Based Infrared System (SBIRS) satellite last year. The problem initially appeared intermittently and then resurfaced more frequently during two months of trial testing in fall 2012.

Speaking with reporters in a conference call, Planeaux said the problem is “with communications on board the vehicle,” as opposed to a ground system.

Planeaux said he believed engineering teams have made “significant progress” in correcting the issue and that the satellite is expected to complete the certification process later this year.

Launched in May 2011, the satellite is the first of a new generation of geosynchronous-orbiting missile warning satellites that will enhance the Pentagon’s ability to detect missile launches around the world. The SBIRS system includes four dedicated satellites in geosynchronous orbit, infrared sensors hosted on classified satellites in highly elliptical orbits, and a network of ground stations to receive, process and distribute the data.

SBIRS is the replacement for the Defense Support Program constellation of satellites that have provided missile warning since the early 1970s. The newer satellites, featuring scanning sensors that cover large swaths of territory and staring sensors that focus on smaller areas of interest, are expected to significantly improve the Pentagon’s missile detection and military-intelligence gathering capabilities.

The on-orbit glitch with the SBIRS GEO-1 satellite is the latest problem in a program that has been beset with extensive delays and cost overruns. Lockheed Martin Space Systems of Sunnyvale, Calif., is prime contractor on the multibillion-dollar program.

The second dedicated satellite, GEO-2, is expected to launch from Cape Canaveral Air Force Station, Fla., on March 19.

Planeaux said Air Force officials have not detected a similar communications issue in ground tests of GEO-2, and expect that any comparable problem that crops up after launch could be solved by a software update. GEO-2 should be certified about six months after launch, he said.

The third geosynchronous satellite, GEO-3, is expected to launch in 2015, with the fourth to follow about a year later.

Planeaux said he expects the Air Force to issue production contracts for the fifth and sixth satellites later this year.

Dave Sheridan, SBIRS program manager for Lockheed Martin, said he expected to turn in a production schedule for the fifth and sixth satellites to the U.S. Defense Department April 1.

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...