The construction of four Scorpene-class attack submarines for the Brazilian Navy was launched on Saturday at a plant near Rio de Janeiro. Brazil and France signed a $4.25-billion contract on the construction of the four enlarged S-BR diesel-electric submarines, jointly designed by France and Spain, in 2008. The first submarine is expected to enter service in 2017. Scorpene-class submarines are equipped with six 533-mm torpedo tubes for 18 torpedoes or SM.39 Exocet anti-ship missiles, or 30 mines in place of torpedoes. Unlike other modifications of the Scorpene-class submarine, the S-BR submarine is not equipped with an air-independent propulsion (AIP) system which allows a submarine to operate without the need to surface or use a snorkel to access atmospheric oxygen. Brazilian President Dilma Rousseff, who was present at Saturday\'s ceremony, said the construction of the submarines was an important step that would help the Brazilian Navy reach a new level of technological development. Brazil and France have also signed an agreement to develop a French/Brazilian nuclear powered submarine. In line with the deal, Brazil\'s first nuclear submarine is scheduled to enter service in 2023.