the Space-Based Infrared System. SBIRS-High will consist of next-generation early-warning satellites in geostationary or highly elliptical orbits. SBIRS-Low will consist of satellites in low-earth orbit that are designed to track missiles under powered flight (when they are very bright if viewed in infrared light) as well as warheads that are gliding through space (which are much harder to observe).

the Space-Based Infrared System. SBIRS-high consists of next-generation early-warning satellites in geostationary or highly elliptical orbits. SBIRS-low consists of 24 satellites in low-Earth orbit that are designed to track missiles under powered flight (which are very bright when viewed in infrared light) as well as warheads that are gliding through space and thus are much harder to observe.