AKA: Energia M. Status: Development ended 1993. Thrust: 1,960.00 kN (440,620 lbf). Gross mass: 272,000 kg (599,000 lb). Unfuelled mass: 28,000 kg (61,000 lb). Specific impulse: 455 s. Specific impulse sea level: 352 s. Burn time: 550 s. Height: 20.00 m (65.00 ft). Diameter: 7.70 m (25.20 ft). Span: 7.70 m (25.20 ft).