Fusion rocket engines are analyzed as electric propulsion systems, with propulsion thrust-power-to-inputpower ratio (the thrust-power "gain," Gt) much greater than unity. Gain values of conventional (solar, fission) electric propulsion systems are always quite small (e.g, Gt 0.8). With these, "high-thrust" interplanetary flight is not possible, because their system acceleration (at) capabilities are always less than the local gravitational acceleration. In contrast, gain values 50-100 times higher are found for some fusion concepts, which offer "high-thrust" flight capability. One performance example shows a 53.3 day (34.4 powered; 18.9 coast), one-way transit time with 19% payload for a single-stage Earth/Mars vehicle. Another shows the potential for highacceleration (at = 0.55 g0) flight in Earth/moon space. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.
