Space-Based Infrared System

Background

After Iraq launched short-range theater missiles during the 1991 Persian Gulf War, the U.S. Department of Defense decided that expanded theater missile warning capabilities were needed and began planning an improved infrared satellite sensor system for both long-range strategic and short-range theater ballistic missile warning and defense. In 1994, the DoD studied consolidating various infrared space requirements—ballistic missile warning and defense, technical intelligence, and battlespace characterization—and chose SBIRS to replace and enhance the Defense Support Program (DSP).

DSP satellites, which had provided early warning for long-range ballistic missile launches for over 30 years, used infrared detectors to sense missile plumes. Earlier attempts to replace DSP—the Advanced Warning System in the early 1980s, the Boost Surveillance and Tracking System in the late 1980s, and the Follow-on Early Warning System in the early 1990s—failed, according to the Government Accountability Office, because of immature technology, high cost, and affordability issues.

SBIRS uses more sophisticated infrared technologies than DSP. The original contract included two SBIRS HEO sensors and two to three SBIRS GEO satellites, with an option to buy a total of five GEOs. A planned low Earth orbit component, SBIRS-Low, was moved into the Space Tracking and Surveillance System program. SBIRS experienced Nunn-McCurdy breaches in 2001 and 2005; by September 2007, the expected project cost had grown to US$10.4 billion.

SBIRS High

SBIRS High, now often called simply SBIRS, consists of four dedicated satellites in geosynchronous Earth orbit and sensors on two host satellites in highly elliptical orbit, replacing the Defense Support Program satellites to provide enhanced strategic and theater ballistic missile warning. The first GEO satellite, SBIRS GEO-1, launched on 7 May 2011. Two hosted sensors on classified satellites—likely from the NROL-22 (USA 184) launch in 2006 and NROL-28 (USA 200) launch in 2008—are believed by analysts to be ELINT satellites in the JUMPSEAT and TRUMPET family; TRUMPET has been reported to carry an infrared sensor called HERITAGE.

Lockheed Martin is the prime contractor, with Northrop Grumman as the major subcontractor; Lockheed Martin also provides the SBIRS GEO satellite. Deployment was delayed from December 2009 to 2011 because of workmanship problems including unresolved software malfunctions and broken solder joints in a gyroscope assembly on the first spacecraft. SBIRS GEO-1 launched successfully on 7 May 2011. The first two GEO satellites began operations in 2013.

SBIRS GEO-3 launched on 20 January 2017, and SBIRS GEO-4 on 20 January 2018. In 2017, the Air Force requested US$1.4 billion for Fiscal Year 2018 and advance procurement for SBIRS 7 and 8. Fiscal Year 2019 provided US$643 million for SBIRS, but funding for SBIRS 7 and 8 was eliminated in favor of the Next-Generation Overhead Persistent Infrared program. SBIRS GEO-5 launched on 18 May 2021, and SBIRS GEO-6 on 4 August 2022.

SBIRS Low (Space Tracking and Surveillance System)

The SBIRS Low contract, originally expected to consist of about 24 low Earth orbit satellites, was transferred to the Missile Defense Agency and renamed the Space Tracking and Surveillance System (STSS). Its primary purpose was tracking ballistic missiles and discriminating between warheads and other objects such as decoys that separate from missile bodies during the middle portion of flight. The system was to have two major sensors coordinated by an on-board computer: a scanning infrared sensor to acquire ballistic missiles in early flight, and a tracking infrared sensor, cooled to very low temperatures, to follow missiles, warheads, debris, and decoys during later stages.

The original deployment schedule was 2010, when the National Missile Defense System was said to need its capabilities. In 2001, the Missile Defense Agency assessed programs for a national ballistic missile defense system and found them lacking in space; it absorbed SBIRS Low in its early development and renamed it STSS, changing the program's direction somewhat while keeping the overall mission of detecting and tracking ballistic missiles through all flight phases.