The U.S. Air Force has awarded Lockheed Martin Space Systems of Sunnyvale, Calif., a $42 million contract modification for work on the fifth and sixth satellites in the Space Based Infrared System (SBIRS) for missile warning, according to a Sept. 19 announcement from the Pentagon.

Congress last summer authorized the Air Force to spend $3.9 billion to purchase those satellites, called GEO-5 and GEO-6.

The money will be used for nonrecurring engineering and long-lead materials.

This is the second long-lead contract the Air Force has awarded on the satellites this year. In February, Lockheed Martin received a $284 million contract for advanced procurement for GEO 5-6 program.

Lt. Gen. Ellen M. Pawlikowski, commander of the Air Force Space and Missile Systems Center, wrote in the September edition of Air & Space Power Journal that the service plans to time the staffing ramp-up on GEO 5-6 to coincide with the GEO/HEO 3–4 effort ramp-down. 

The SBIRS system consists of dedicated satellites in geosynchronous orbit complemented by infrared missile warning sensors aboard classified satellites operating in highly elliptical orbit, or HEO.