DUAL-FUEL PROPULSION IN SINGLE-STAGE ADVANCED MANNED LAUNCH SYSTEM VEHICLE

As part of the United States Advanced Manned Launch System study to de termine a follow-on, or complement, to the Space Shuttle, a reusable s ingle-stage-to-orbit concept utilizing dual-fuel rocket propulsion has been examined. Several dual-fuel propulsion concepts were investigate d, These include: a separate-engine concept combining Russian RD-170 k erosene-fueled engines with space shuttle main engine-derivative engin es; the kerosene and hydrogen-fueled Russian RD-701 engine; and a dual -fuel, dual-expander engine. Analysis to determine vehicle weight and size characteristics was performed using conceptual-level design techn iques. A response-surface methodology for multidisciplinary design was utilized to optimize the dual-fuel vehicles with respect to several i mportant propulsion-system and vehicle design parameters in order to a chieve minimum empty weight. The tools and methods employed in the ana lysis profess are also summarized. In comparison with a reference hydr ogen-fueled single-stage vehicle, results showed that the dual-fuel ve hicles were from 10 to 30% lower in empty weight for the same payload capability, with the dual-expander engine types showing the greatest p otential.