NAA HATV

North American's HATV proposal was an ogival single-stage-to-orbit vehicle, with tanks made from 18-8 stainless steel. In common with other HATV designs, the tanks had to be pressurized to maintain rigidity.

The tanks were pressurized via gas bottles in the engine compartment and not insulated. Instead insulation blankets shrouded the vehicle on the pad, and were jettisoned at lift-off.

Propulsion was via a single central high-expansion ratio engine of 325 kN thrust, surrounded by eight low-expansion ratio engines of 127 kN thrust each. As propellant was exhausted and higher altitudes were reached, the low-expansion engines would be throttled back, allowing the more efficient, higher specific impulse central engine to provide most of the delta-V to orbit.

The ascent profile involved flight to 90 km altitude, where the liquid engines would shut down. After coast to apogee half a world away, four small solid motors would fire to circularize the orbit at 280 km altitude.

Two all-moving slab tailfins provided roll stability. Pitch and yaw control were provided by throttling the eight peripheral motors.

The HATV components would be delivered horizontally by rail to the pad and stacked vertically using a gantry crane. Propellant during fuelling would also be delivered via tank cars by rail. The gantry would roll back for launch, and a water deluge would cool the pad to minimize damage during launch.

to: 280 km orbit.