The Tupolev Tu-144 (NATO reporting name "Charger") is a retired jet airliner, which was the world's first commercial supersonic transport aircraft (SST). It is one of only two SSTs to enter commercial service, the other being the Anglo-French Concorde. The design was constructed in the Soviet Union under the direction of the Tupolev design bureau, headed by Alexei Tupolev. Throughout its 55-flight operational history, the Tu-144 flew at an average service altitude of 16,000 metres (52,000 ft) and cruised at a speed of around 2,000 kilometres per hour (1,200 mph).