Artist’s rendition of an SBIRS satellite. Photo: Lockheed Martin.

[Via Satellite 10-09-2014] Lockheed Martin and Northrop Grumman have shipped the payload for the United States Air Force’s fourth Space-Based Infrared System (SBIRS) satellite to Lockheed Martin’s Sunnyvale, Calif. facility. After receiving the payload on Sept. 30, engineers are completing its integration to have it ready for delivery to the Air Force in 2016.

The SBIRS GEO 4 satellite carries two advanced sensors for missile warning and surveillance information. A scanning sensor covers wide swaths of the Earth’s surface to identify missile launches and other activity, while a more focused staring sensor is tasked with pinpointing areas of interest. This dual approach is expected to improve sensitivity while also shortening the revisit time compared to legacy spacecraft.

The Air Force Space Command is currently using the GEO 1 and GEO 2 satellites following operational acceptance in 2013. The third satellite, GEO 3, is in the process of vacuum testing. The Air Force has contracted Lockheed Martin for GEO 5 and 6.