The United Launch Alliance (ULA) successfully launched the SBIRS GEO-5, TDO 3 and TDO 4 satellites into a GTO orbit at 1737 GMT on 18 May on an Atlas V 421 vehicle (using a pair of the standard AJ60A solid rocket boosters) from Cape Canaveral Space Force Station, Florida, USA. The primary payload SBIRS GEO 5 is a part of the military Space Based infrared System programme. These satellites provide a missile launch detection service enabling early warning activities. Also on-board were the TDO-3 and -4 CubeSats which are technology demonstration satellites for the US Air Force Academy. The Centaur upper stage debuted the RL1-C1-1 engine for the Atlas series.
Phil Hylands contributed to this article.