High-elevation equatorial catapult-launched RBCC SSTO spaceplane for economic manned access to LEO

<p>A conceptual and feasibility study of an RBCC SSTO catapult-launched reusable strap-on parallel-boosted gliding-reentry lifting-body spaceplane for economic manned short-duration 300-kg payload LEO access is presented and discussed. One or more high-elevation equatorial spaceports are proposed each having magnetic-levitation catapult-launch mechanisms for subsonic to supersonic launches, adjacent paved runways, and on site facilitates to produce cryogenic propellants. High-elevation equatorial launch sites provide less dense atmosphere, less distance to LEO, and the possibility to launch into any orbital plane. The launch window for zero-inclination direct equatorial orbits requiring minimum specific energy and providing maximum specific payload capability of any existing launch system is continuously open and rendezvous opportunity frequent. Combined equatorial catapult launch and high-altitude facilities propulsion reduces energy requirements by about 500-600 m/s making it perhaps the most efficient future terrestrial launch system. Additionally, the use of airframe-integrated ramrocket RBCC engine further increases specific impulse for the portion of transatmospheric flight thus further reducing propellant requirements. Due to the fact that the proposed spaceplane is relatively small, the technical, organizational, and safety requirements are much relaxed. Substantially lower operational cost are expected per flight. The first cost analysis suggests about $3,000/kg for payload to LEO. The fact remains that SSTO is a very marginal concept and that RBCC engines still need flight test proving. Without more energetic propellants and very efficient RBCC propulsion devices perhaps in combination with air launches or terrestrial catapult launch facilities there seems nothing on the horizon that could make SSTO concept truly practical.</p>