Sled-launched single stage to orbit vehicle with air-breathing propulsion to Mach 5 (subsonic combustion). The sled would accelerate the launch vehicle to Mach 0.8. Propellants wer slush hydrogen and liquid oxygen. The vehicle would have a 3000 km cross-range on re-entry.

LEO Payload: 9,000 kg. to: 200 km Orbit. at: 51.0 degrees. Total Mass: 300,000 kg. Core Diameter: 19.7 m. Total Length: 54.1 m.