Gross Mass: 2,721,000 kg.
Empty Mass: 245,000 kg. Thrust (vac): 2,721,000 kgf. Isp: 428 sec. Burn time: 383 sec. Propellants: Lox/LH2Diameter: 18.3 m. Span: 18.3 m. Length: 50.5 m. Country: USA. No Engines: 4. M-1Status: Study 1963. Comments: Operational date would have been February 1973 .