RTLS abort mode elimination using the Space Shuttle-Liquid Flyback Booster launch system

Abstract

Liquid Fly Back Boosters (LFBB), also known as Reusable First Stage (RFS), are proposed replacements for the Space Shuttle's Solid Rocket Boosters (SRBs). They were studied by Boeing Reusable Space Systems, and Lockheed Martin under contract to NASA Marshall Space Flight Center. The RFS concept studies continue as part of NASA's Second Generation Reusable Launch System Risk Reduction Program, as an element of the Shuttle Derived Vehicle (SDV) concepts being investigated by both contractors and NASA. The LFBB could potentially eliminate the need for the Return to Launch Site (RTLS) abort mode the Shuttle is currently forced to use for abort situations that occur from liftoff until launch plus 4 minutes and 20 seconds. A Fortran model of a nominal launch trajectory was perturbed to simulate a single Space Shuttle Main Engine-out (SSME-out) abort scenario at different times during a high inclination (51.6°) launch with the goal being to abort to the southern most landing site possible. The model accounted for lift, drag, dynamic pressure, throttling times and included atmospheric effects to enhance fidelity. Results show that indeed RTLS can be feasibly eliminated and successful landings made as far south as Savannah Georgia and Charleston South Carolina. This success is attributed to the throttling capability of the Liquid Fly Back Booster engines.