Missile Warning Sensor Heads to Launch Prep

Northrop Grumman shipped the fourth Space Based Infrared System Highly Elliptical Orbit payload last month for integration with its hosting payload in preparation for eventual launch, officials announced on June 16. “HEO-4 will complete the replenishment of our polar missile warning capability, ensuring continuity of this critical operational capability” by replacing HEO-2, Space and Missile Systems Center Commander Lt. Gen. Samuel Greaves. HEO-3, which replaced the earlier HEO-1 payload completed on-orbit checks last month. The hosted infrared scanning and staring sensors augment SBIRS’s two satellites in geosynchronous orbit, providing missile early warning coverage alongside Defense Support Program satellites. The HEO sensor specifically provides launch detection from northern latitudes, according to the release. Northrop Grumman was awarded a contract last year to eventually refresh the rest of the constellation, supplying the GEO-5 and GEO-6 satellites when the first two reach the end of their service lives.