For our first launch this week, on May 18 at 17:31 UTC, an Atlas V 421 launched the SBIRS GEO-5 mission into geostationary transfer orbit from SLC-41 at Cape Canaveral Space Force Station in Florida. The 421 in the rocket name means that the Atlas V has a four meter payload fairing on top of its Centaur upper stage, two solid boosters on the first stage, and a single RL-10 engine on the second stage Centaur.

SBIRS stands for Space Based Infrared System, and is the current system used by the US government to detect intercontinental ballistic missile launches. It replaces the Defense Support Program which was launched in the 1970s. SBIRS uses two different sensors: a scanning sensor and a staring sensor. The scanning sensor is used to provide “quicker revisit time” over wide areas and the staring sensor is used to look at smaller areas for longer times.

More Information

Defense Support Program Satellites (U.S. Air Force)

SBIRS-GEO info page (Gunter’s Space Page)

Launch video