Slide 27 of 125
Martin Marietta's unsolicited company-funded shuttle proposal was named “Spacemaster”. It was designed for carrying 11,340-22,680 kilogram payloads in the same 4.57 * 18.3-meter cargo envelope as the other Phase A shuttle proposals. Martin's twin-body booster (center) would have reduced the overall length of the mated vehicle (top, left) and would also have been compatible with different orbiters or rocket stages between bodies. The booster rocket engines are on the aft end of each body. Since the orbiter (right) would be nested during ascent, Martin Marietta predicted that the center of gravity shift from liftoff to staging would be relatively small. The nested orbiter design would also have reduced booster rocket engine gimbal angles, ascent drag and vehicle angle of attack. The booster landing jet motors were installed in the forward wing to achieve a good center-of-gravity location.
Liftoff Thrust: 2,539,680 kgf. Total Mass: 1,587,302 kg. Core Diameter: 8.0 m. Total Length: 128.0 m.
Stage Number: 1. 1 x Spacemaster-1 Gross Mass: 1,224,490 kg. Empty Mass: 203,342 kg. Thrust (vac): 2,863,622 kgf. Isp: 442 sec. Burn time: 155 sec. Isp(sl): 392 sec. Diameter: 8.0 m. Span:
45.1 m. Length: 57.9 m. Propellants: Lox/LH2 No Engines: 14. SSME Study
Stage Number: 2. 1 x Spacemaster-2 Gross Mass: 362,812 kg. Empty Mass: 80,000 kg. Thrust (vac): 463,874 kgf. Isp: 459 sec. Burn time: 276 sec. Isp(sl): 359 sec. Diameter: 6.7 m. Span: 32.6
m. Length: 48.8 m. Propellants: Lox/LH2 No Engines: 2. SSME Study
“Progress in Technology for Space Shuttles”-- Rainey, AAS 1970/vol.28/p. 3
”Space Shuttle” -- Dennis R. Jenkins, 1981, ISBN: 0963397451