Gross Mass: 395,000 kg.
Empty Mass: 18,000 kg. Thrust (vac): 1,270,000 kgf. Isp: 400 sec. Burn time: 117 sec. Propellants: Lox/LH2Isp(sl): 340 sec. Diameter: 8.5 m. Span: 12.2 m. Length: 11.0 m. Country: USA. No Engines: 8. Helios Stage 1Status: Study, Ehricke, 1960. Comments: Booster stage with Lox tanks only to take nuclear second stage to stratosphere. .