The contract for the initial work on satellites 5 and 6 is worth $82 million.
"This initial contract will sustain a steady production rate and by the Air Force acquiring satellites in bulk, rather than one at a time, we can significantly reduce costs by achieving economies of scale," said Jeff Smith, vice president of Lockheed Martin's Overhead Persistent Infrared mission area.
"We understand both the importance of the SBIRS mission and the weight of the current fiscal environment and we are committed to delivering mission success affordably and efficiently for the Air Force."
SBIRS satellites and payloads, placed in a highly elliptical orbit, deliver improved missile warning and intelligence and battlespace awareness.
Under the contract for first-phase work, Lockheed Martin will complete non-recurring engineering activities for the satellites and procure long-lead spacecraft parts.
Previous SBIRS contracts given to Lockheed have included four payloads, four GEO satellites, and ground systems for processing and disseminating data from the satellites.
The first SBIRS satellite has been launched and the second is to be launched in March.