BOEING

Slide 44 of 125

Boeing also investigated several different classes of VTVL TSTO for solar power satellite heavy-lift missions. Like the "Leo" single-stage-to-orbit rocket, the TSTO would have landed vertically at sea or land by way of a ballistic entry through the Earth's atmosphere with parachutes and/or retrorockets providing a soft landing. An actively cooled metallic heat shield would be used. The smallest version (depticted above) would have had a net payload of 91,000kg. The 526-tonne (dry wt.) first stage was powered by nine LOX/kerosene engines plus three SSMEs for landing while 7 SSMEs were used on the 217-tonne second stage. The evaluation was discontinued in early 1978 due to operational considerations, and the studies focused on larger VTVL TSTO versions instead. Boeing estimated that the VTVL TSTO could reduce the cost per kilogram to orbit to $30/kg [1976 $] or only three times the cost of the propellant required to operate the vehicle.

Heavy-lift launch vehicle booster/orbiter staging at 65km altitude.

Liftoff thrust: 157,506KN (sl). Total Mass: 10,000t. Total length: 73m.

Payload capability: 400t to a 92.6km x 500km low Earth orbit.

Cost per flight: $7 million [1976 $] Stage 1 : 6 x SSMEs & 16 x LOX/kerosene gas generator cycle engines. Liftoff thrust: 6 x 2,091KN + 16* 9,060KN. Isp: 350s. Gross Mass: 8,243.39t. Empty Mass: 787.59t. Length: 23.81m. Diameter: 33.68m. Propellants: LOX/LH2+kerosene.

Stage 2 : 8 x SSMEs. Liftoff thrust: 9 x 2,091KN . Isp: 455.2s [vac.]. Gross Mass: 1,750t including payload. Empty Mass: 258.81t. Length: 49.15m. Diameter: . Propellants: LOX/LH2.

This illustration depicts the medium-capability version of Boeing's VTVL TSTO (left) along with the “Leo” VTVL SSTO (center) and a NASA/Johnson Space Center VTHL TSTO concept (right). All three vehicles would have a 272-tonne payload capability and the average turn time (incl. water recovery of the booster 300km downrange) for Boeing's TSTO vehicle would be 7-8 days.

”Space Transportation Systems 1980-2000” -- Salkeld,Patterson & Grey, AIAA Aerospace Assessment 1978/Vol.1