Chemical Automatics Design Bureau (KBKhA) RD-0124, also designated 14D23, is a four-chamber oxidizer-rich staged-combustion liquid-oxygen/kerosene engine for the third stage of Soyuz-2.1b, Soyuz-2.1v, and Soyuz-STB. KBKhA reports 30 metric-ton-force (approximately 294.2 kN) vacuum thrust, 359 s vacuum specific impulse, and 300 s main-mode operation; it records first flight in 2006 and continuing commercial deliveries.