Northrop Grumman Corp. has delivered the second geosynchronous orbit (GEO) payload to prime contractor Lockheed Martin Space Systems Co. in Sunnyvale, California, for integration into the spacecraft and final system-level testing.

The payload will be installed on the GEO-2 spacecraft, which will fly in geostationary orbit around the Earth. The U.S. Air Force SBIRS program is designed to provide early warning of missile launches and simultaneously support other missions including missile defense, technical intelligence, and battlespace awareness. The GEO-2 payload consists of a scanning sensor and a staring sensor, along with other key spacecraft subsystems and electronics including a pointing and control assembly (PCA). The scanning sensor is designed for continuous observation and surveillance of traditional intercontinental ballistic missile threats, and will have performance similar to the highly elliptical orbit (HEO) sensors already on orbit. The staring sensor is designed to detect very low signature, short-burn-duration theater missiles and other transient events of interest. Together, the sensors contain nearly one million detector elements in their two focal planes.

The PCA is a major subsystem of the GEO-2 payload developed by Lockheed Martin. It uses highly agile, precisely pointed mirrors to allow the spacecraft's optical telescopes to scan and stare at designated areas, enabling operators to modify the areas of surveillance according to national priorities. This milestone closely follows an extensive thermal vacuum testing program conducted by Northrop Grumman earlier this year which demonstrated all four SBIRS mission areas — missile warning; theater missile warning and defense; technical intelligence; and battlespace awareness. The GEO-2 payload was exercised over the full range of backgrounds, including severe infrared clutter conditions that the payload might see when observing Earth, and multiple point sources representing targets in flight. Full interconnected and cross-strapped redundancies were tested through six thermal cycles, from on-orbit cold to on-orbit hot.

During the integration and test phase, Lockheed Martin will demonstrate and test all interfaces, command structures, control and function of the combined payload and spacecraft. The GEO-2 satellite is scheduled for launch in 2011. Lockheed Martin's current SBIRS contract includes the two HEO payloads now on-orbit, two GEO satellites, as well as ground-based assets to receive and process the infrared data. The program is in the process of adding additional GEO spacecraft and HEO payloads to the planned constellation. The SBIRS team is led by the Space Based Infrared Systems Wing at the U.S. Air Force Space and Missile Systems Center at Los Angeles Air Force Base. Air Force Space Command operates the SBIRS system.